The Aging Eye: Preventing and treating eye disease

Rediscover Your Vision

Heres What Rediscover Your Vision Can Do To Help You: Improve and perfect your eyesight so that you dont need your readers nearby every single time you need to read the newspaper, a report, a book, or a document. Strengthen your eyes and focal muscles, eliminating the painful burning sensation in your eyes at the end of every single day. Use a computer or watch TV without pain and suffering anytime, anywhere, and as long as you want. Improve All aspects of your vision. Whether youre nearsighted or farsighted, the condition can be cured! See road signs from far away, watch a movie, play catch or read a book with just a lamp on, without stressing about carrying your glasses around everywhere! Start your day comfortably, without worrying about taking half an hour to pop your uncomfortable contacts in, or scrambling to find your glasses. Save Thousands and Thousands of dollars. I cant stress enough how expensive glasses and contacts are getting nowadays, and the prices just keep Increasing. If you spend $500 a year on glasses and contacts, imagine how much money youd have to spend on things like vacations and luxuries over the 40-50 years you have to Keep buying them!

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Ophthalmology Seeing The Light

Ophthalmology is the branch of medicine that provides the complete medical and surgical care of the eye and related structures of the visual system (extraocular muscles, eyelids, orbit, nerves, visual pathways, and more). Yes, they can (and often do) prescribe glasses and contact lenses. But their spectrum of care extends much further. It requires mastery of the anatomy, physiology, microbiology, and pathophysiology of the eye, as well as an understanding of optical physics. To treat ocular and visual disorders, ophthalmologists are really both internists and surgeons.

Ophthalmology As A Hightech Field

Ophthalmologists love gadgets and technical breakthroughs. Their offices are filled with a wide range of instruments ranging from simple ophthalmoscopes to complicated operating microscopes. In the last few decades, there has been an explosion of new technology in the visual sciences, which has resulted in several promising new techniques and advances. Diagnostic and surgical breakthroughs in this specialty include laser photocoagulation, micromanipulation, fluorescein angiography, and microsurgery. To be a good ophthalmologist and make the most of this technology, the specialty requires excellent visual and motor skills, depth perception, and color vision. Pharmacologic treatments are important in ophthalmology. Primary open angle glaucoma, for instance, remains one of the largest causes of blindness in the world, affecting over 5 million people.2 Traditionally, topical beta-blocking medicine provided the main form of therapy, but several side effects limited their usefulness in...

The Ophthalmologyoptometry Distinction

Many medical students interested in a possible career in ophthalmology are confused by the role of optometrists, who are often mistakenly referred to as eye doctors by the general public. Where exactly do these health professionals fit into the spectrum of vision care Optometrists, after all, are not licensed to practice medicine only optometry. Although some states permit optometrists to prescribe limited topical medications, no optometrists are given privileges (or even training) for performing ophthalmologic surgery. Their expertise lies in understanding and treating problems with the optics of the eye. They prescribe the majority of corrective lenses in this country and also diagnose diseases of the eye that may or may not require referral to an ophthalmologist. Instead of competing with each other, most ophthalmologists and optometrists have mutually beneficial relationships. As the medical doctor with extensive clinical and surgical training, ophthalmologists are specialists in...

Pediatric Ophthalmology

This specialty involves the eye care of the pediatric population, as well as the treatment of certain conditions such as strabismus (deviation of the eye from its normal visual axis) that can occur in both children and adults. Pediatric ophthalmologists perform surgery on congenital cataracts, repair ptosis (droopy lids), fix strabismus, diagnose childhood eye tumors like retinoblastoma, and treat amblyopia. One of the more common problems, amblyopia is defective vision uncorrectable by glasses in an eye that is otherwise normal it is essentially the result of anything that causes vision in one eye to be better than the other while visual pathways are still developing in early childhood. Because several syndromes have a major impact on vision, this specialty also affords the opportunity to work with special needs children. Last, pediatric ophthalmologists work with premature infants they monitor and treat the ocular sequelae of prematurity along with retinal surgeons.

Slit Lamp Exam of the Prospective Contact Lens Patient

The result of the slit lamp examination is one of the determining factors in whether or not a patient can try contact lenses. Here is a basic list of things that the fitter will want to know 3. Conjunctiva Is there any redness (If yes, give location and grade.) Are there any growths that might interfere with the location of a contact lens Are there any papillae or follicles on the palpebral conjunctiva

TABLE 58 Types of Cataracts

Posterior Capsular Opacification Grading

Index of refraction of nucleus increases, inducing myopia the world appears yellower as the lens acts as a filter for blue wavelengths Typically PSC types Anterior subcapsular opacities Anterior lens capsule exfoliation Sunflower cataract in subcapsular cortex Brownish subcapsular opacity PSC type PSC type Usually hereditary commonly remains stationary throughout life visual acuity is only affected if opacity is large Grading Cortical Cataracts Figure 5-32. Nuclear sclerotic cataract. (Photo by Val Sanders.) intraocular lens (IOL) - plastic implant inserted during or after cataract surgery. If the lens is in front of the iris, it is an AC lens. If the lens is AC but clipped into the iris (with pegs or clips), it is an iris plane. An IOL behind the iris and pupil is a PC lens. The lens should be centered, but rarely they slip or drift (this is best seen after dilation). posterior subcapsular cataract (Figure 5-33) - whitish opacity on the far back part of the lens. Can be hard to see...

Abnormal visual experience and amblyopia

Visual disorders that occur in early childhood, such as strabismus (crossed eyes) and anisometropia (monocular defocus), are associated with amblyopia, literally meaning blunted vision. Visual acuity and contrast sensitivity in the amblyopic eyes of monkeys and humans are reduced, but not nearly so severely as they are following visual deprivation (Blakemore and Vital-Durand, 1981 Harwerth et al., 1983 Kiorpes, 1992b, 1996, 2001 Kiorpes et al., 1987 Kiorpes et al., 1993 Kiorpes and Movshon, 1996 Levi and Carkeet, 1993 Smith et al., 1985). Figure 12.7A shows the development of spatial resolution in each eye of a population of strabismic monkeys (Kiorpes, 1992b) and compares it to the development of resolution in normal monkeys tested monocularly. Resolution in the fellow (nondeviating) eyes develops normally, but resolution development in the strabismic eyes lags. Figure 12.7B illustrates losses in contrast sensitivity for three monkeys, each made experimentally amblyopic by a...

Why Consider A Career In Ophthalmology

There are many reasons why talented medical students should consider a career in ophthalmology. In a survey of residents,5 they listed the following factors as the most influential in their decisions to pursue a career in ophthalmology, ordered from most to least influential surgery, patient contact, lifestyle, junior senior year electives, previous contact with ophthalmologists, potential income, and status among peers. Extrapolating from this study, the most important factors in choosing a career in ophthalmology are historically those inherent to the practice of ophthalmology and to patient care. Despite the fact that many medical students do not complete electives in this field, the desirability of ophthalmology remains high because of what it has to offer a future physician. Ophthalmology is an exciting and challenging field that involves the complete care of the patient. It offers physicians the opportunity to practice preventive medicine, medical management, and surgical...

Myopia Shortsightedness

Shortsightedness (myopia) blurs distance vision (e.g., the board in class), and the prescribing of spectacles for myopia by eye care practitioners is usually a fairly straightforward decision. An optometrist might consider prescribing a refractive correction if the myopia reduced the binocular visual acuity to 6 9 and would almost certainly prescribe if it was reduced to 6 12. Low to moderate myopia will not impair near vision and some studies have even found a correlation between myopia and above-average reading performance (Evans, 2001).

Visual Acuity and Refractive Error Visual Acuity

Visual acuity refers to the angular subtense of the smallest size of detail that the eye can resolve. It is usually expressed as a fraction where the numerator refers to the testing distance in meters (feet in the United States). Six meters is the reference distance (20 feet in the United States), and the denominator changes proportionally according to the change in size of the lettering, while reading from the same reference distance. The easiest way to interpret a visual acuity is to divide out the fraction. For example, average visual acuity is 6 6 (in feet, 20 20), which divides out to 1.0, or 100 . Although this is the theoretical normal level of visual acuity, most children do better than this, typically achieving 6 4 (20 30), which divides out at 1.5 or 150 . The bottom line of many letter charts is 6 3 (half the size of 6 6 letters), and the top line of most letter charts is 6 60. A 6 60 letter is 10 times the size of a 6 6 letter and 6 60 divides out at 0.1 or 10 of normal...


There is more than one way to remove a cataract. However, at the time of this writing, the use of phacoemulsification is most common. In this case, sutures are usually not used. In any event, the following is a general guideline to slit lamp examination following cataract surgery.

Vision Impairment

With better control of nutrition and of maternal and childhood infections (such as smallpox and maternal rubella), inherited disorders account for a large fraction of congenital and childhood visual impairment. Estimates are that half of all visual impairment before the age of 45 years has a genetic etiology all inheritance patterns are represented including single gene, mitochondrial, and chromosomal (Robinson and Linden, 1993). Obtaining medical documentation of the type and degree of visual disturbance is absolutely essential to provide genetic counseling. Retinal dystrophies are the most common form of genetic blindness (accounting for more than 50 ) (Aldred et al., 1994). More than 200 inherited disorders involve retinal degeneration (usually presenting as night blindness and eventual loss of central vision) (Heckenlively and Daiger, 1997). Conversely, 10 of all inherited disorders involve the retina directly or indirectly (Heckenlively and Daiger, 1997). The important...


For students who cannot make up their minds between neurology and ophthalmology, it is possible to have the best of both worlds. Neuro-ophthalmology involves both central nervous system disease and its effect on the visual pathways, as well as disease processes inherent to the nerves and pathways of the eye. Because about 65 of all intracranial processes have ophthalmic manifestations, the importance of this subspecialty is obvious. Although some neuro-ophthal-mologists operate on a limited basis and are more involved with the recognition and diagnosis of disease, others perform complicated surgeries on the eye and orbit, such as orbital wall decompressions for Grave eye disease. This procedure involves the precise removal of areas of orbital bone to alleviate the exophthalmos (forward protrusion) of the eye that results from the swelling of orbital tissues as can occur in thyroid disease.

Earlyonset Cataracts

Approximately 1 250 infants are born with a cataract (Robinson and Linden, 1993). Worldwide, 10 of all blindness is attributed to congenital cataracts (Rabinowitz et al., 1997). Cataracts seem to be involved in the aging process, for all humans will develop cataracts that can impair vision if they live to an advanced age. The upper age limit that is considered early for the onset of cataracts is debatable (R. Kalina, personal communication). Determining the significance of a family history of cataracts can be sorted by the age of presentation of the cataracts (congenital infancy, < 12 months childhood, 1-15 years and adult, > 15 years). Approximately 70-75 of congenital cataracts Document with ophthalmologic records the area of visual pathology (some conditions will overlap in more than one area) Lens (e.g., cataract, ectopia lentis) Eyeball or globe (e.g., high myopia, glaucoma, structural defect such as microphthalmos or anophthalmos) Did the mother of the person with visual...

American Association of Neurological Surgeons

The primary cause of the failure to develop a normal visual pathway is a squint in very young children, in which only one eye focuses on a selected object while the brain suppresses a different image from the other eye. The problem could also develop as a result of congenital cataracts or severe focusing errors in a young child (such as when one eye is normal and the other has a severe astigmatism that causes a blurry image). Amblyopia must be treated as soon as possible after age eight, it is physiologically too late for the brain to make proper connections in the visual pathway. For amblyopia caused by squinting, the patient must cover the good eye to force the poor eye to function normally. Glasses or surgery to place the deviant eye in the correct position may also be required. Glasses may also help correct severe focusing errors, and congenital cataracts may be removed surgically.

Principle of the Transmission Electron Microscope

Objective lens aberrations, foremost (i) the third-order spherical aberration, (ii) chromatic aberration, and (iii) axial astigmatism, ultimately limit the resolution of the microscope. Spherical aberration has the effect that for beams inclined to the optic axis, the focal length is less than for those parallel to the axis. As a consequence, the image of a point becomes a blurred disk. This aberration can be partially compensated by operating the lens in underfocus, which has just the opposite effect (i.e., the focal length being greater for beams inclined to the axis), though with a different angular dependency (see section 3 where this important compensation mechanism utilized in bright-field microscopy is discussed). Axial astigmatism can be understood as an unroundness of the lens magnetic field, which has the effect that the way specimen features are imaged depends on their orientation in the specimen plane. Axial astigmatism can be readily compensated with special corrector...

Recessive Traits In Humans

In most ways, people who lack melanin are just like the rest of us. But even though they are highly diverse in terms of a variety of traits, they do have some features in common, such as their unusual coloring and vision problems. The lack of melanin during development of the eyes causes abnormal routing of the optic nerves into the brain and results in inadequate development of the retina. They often use glasses, but their vision often cannot be corrected to 20 20 acuity with either glasses or surgery. They are unusually sensitive to bright light. Some are legally blind, but others see well enough to drive a car when using special lenses. Some are not blind but have vision problems that can't be helped by corrective lenses. In some cases, skin cancer can

Could You Handle Working in a Predominantly Male Environment

Certain specialties, particularly the more technical ones, are known to be boys' clubs. The most conspicuous are surgery (and surgical subspecialties), emergency medicine, radiology, and ophthalmology. Keep in mind that high levels of testosterone in the workplace can often lead to inappropriate comments, gender bias, and even sexual harassment. In the operating room, for instance, the perpetual locker room mentality often means that female surgeons tend to feel pressure to

Some practical applications for visually impaired people

In many occasions, the characteristics of haptic functioning in totally blind persons and in blindfolded sighted ones have been compared in the preceding chapters. These studies had mainly a theoretical interest allowing, for example, the evaluation of the role of visual representations and of haptic training in the functioning of this modality. Other available works review extensively the state of our knowledge concerning the cognitive consequences of early blindness (for example, Hatwell 2003 Heller 2000 Warren 1994). The last section of this book considers some particular aspects of the visual impairment per se. Starting from what we know now about the possibilities and limits of touch, it addresses the practical consequences of blindness or, more exactly, the techniques and devices that have been developed to compensate, as much as possible, for the perceptual handicap generated by permanent visual deprivation.

Practicing Medicine Part Time

Specialties with highly controllable hours are also as conducive, such as the shift work of emergency medicine, the case-by-case nature of anesthesiology, the scheduled hours of pathology and radiology, and the lack of off-hour emergencies in dermatology and ophthalmology. Even surgeons can work part time. Breast surgeons, for instance, perform mainly elective surgery and can therefore schedule fewer cases and less clinic time each week. Another way to work part time is to arrange for a shared-schedule position with another physician. In this format, each doctor works half time with alternating appointment schedules together, they equal one practitioner. Some even arrange this system with their spouse if both are in the same specialty. In either situation, remember that working part time means sacrificing higher salaries for flexibility. Another disadvantage is that part-time academic physicians are ineligible for tenure, and those in private practice...

Hypermetropia Longsightedness

Most young, normal, eyes have a very low degree of longsightedness (hyper-metropia or hyperopia), and young eyes have an ability to compensate for low to moderate degrees of longsightedness. The eyes compensate by using the power of ocular accommodation (described above) to over focus the eyes and correct the longsightedness. This is a misuse of accommodation, which usually serves to keep the image clear during near vision. A very different function during near vision is convergence, which is a turning in of the two eyes so that they both point at an approaching object. Accommodation keeps near objects clear, and convergence keeps them single (if the two eyes were not pointing at the object of regard, then it would be perceived as double). In the natural world, accommodation and convergence always act together and these two functions are linked in the brain. In other words, a given amount of convergence induces an equivalent amount of accommodation and vice versa. A constant...

Assessment of Refractive Errors

Refractive errors, like most of the things that optometrists measure, can be determined objectively and subjectively. Objective tests require little or no contribution from the patient. Subjective tests require a response from the patient, but invariably include an element of double-checking. It should be stressed that children of any age (including infants) and of any capabilities (even with severe intellectual disabilities) can undergo an eye examination with an optometrist. The principal objective technique for determining the refractive error uses a handheld instrument, the retinoscope, to shine light through the pupil, and to neutralize (with lenses) the rays that are reflected back from the retina. Eye care practitioners rely more on objective techniques when examining younger and less reliable children patient cooperation is not essential for such an eye examination. Sometimes, eye drops are used to relax the accommodative mechanism and thus reveal the full refractive error....

Cigarettes and the brain

Showed tiny points of swelling on brain cells in the central nervous system the myelin sheath on some cells was also missing. These swellings did not appear in the same section of the brain for all patients, but researchers did discover a relationship between the region affected and the patient's symptoms. For example, patients who had vision problems also had disturbances in the occipital lobe of the brain an area that processes vision.

Retinal cell survival and cell death

The most common forms of blindness occur through the death of retinal ganglion cells or photoreceptors. Loss of ganglion cells is the defining characteristic of glaucoma, which remains one of the leading causes of blindness in adults (Quigley et al., 1995). Loss of photoreceptors can involve rods, as in retinitis pigmentosa or cones, as in macular degeneration or both, as in rod-cone dystrophies and various syndromes. A major risk factor for glaucoma is elevated intraocular pressure, which is thought to cause mechanical deformation as the ganglion cells axons leave the eye. This deformation may prevent the retrograde transport of neurotrophic factors. Based on developmental studies showing that brain derived neurotrophic factor (BDNF) is a vital neurotrophic factor for ganglion cells, it has been suggested that BDNF, or agents that mimic BDNF at later points in its pathway of action, might have therapeutic benefit. A second major cause of ganglion cell death in glaucoma is thought to...

Anterior Chamber Intraocular Lens

When a cataract (cloudy lens) is removed, an intraocular lens (IOL) implant is usually placed inside the eye to focus incoming light. In current cataract surgical technique, the IOL generally is inserted behind the iris. Occasionally, certain cases necessitate IOL placement in front of the iris or in the anterior chamber. Anterior chamber IOLs were used more in the earlier years of implants but are still seen.

Manual exploration in spatial localization tasks

Exploration in which the fingers and or the palms of the hands both explored the edges of the disc and gained relative cues, i.e. an impression of the overall arrangement of each shape relative to the others 2. Relative exploration alone 3. Edges exploration alone 4. Pointing and touching each shape in turn, separately this was apparently an attempt to localize the shape in a egocentric frame of reference, since no external cues were available 5. Vision alone, i.e. use of residual vision only without any manual exploration. Results revealed links between mode of exploration and accuracy of reproduction. Errors were lower with the mixed strategy 1 (edge and relative) than with strategies 3 (edge only) and 4 (pointing). This latter strategy leads to the poorest performances and was however dominant (75 ) in the younger totally blind children. Strategy 5, in which the task was performed only with residual vision, was observed in all the younger visually impaired children and in 62 of the...

NGF and monocular deprivation

Intraventricular NGF administration counteracts the effects of monocular deprivation on ocular dominance and visual acuity. Top Ocular dominance distributions for normal rats, rats monocularly deprived during the critical period and rats monocu-larly deprived and treated with NGF throughout the deprivation period (postnatal days 15-45, P15-P45). Cells were classified according to the Hubel and Wiesel criteria, with cells in classes 1 and 7 being monocular and driven exclusively by the contralateral and ipsilateral eye, respectively cells in ocular dominance classes 2 3 and 5 6 being binocular and driven preferentially by the contralateral and ipsilateral eye, respectively and cells in class 4 being binocular and driven equally by the two eyes. It is evident that the shift in ocular dominance distribution in monocularly deprived rats is absent in NGF-treated rats. (Data replotted from Maffei et al., 1992.) Middle A, Visual evoked potentials (VEP) recorded in the visual...

Administration of neurotrophins during dark rearing can replace the lack of visual experience

Without visual experience the visual cortex does not develop normally, and it remains largely immature even after the end of the critical period (Fagiolini et al., 1994 Timney et al., 1978). The classical signs of dark-rearing effects on cortical development are reported in Figure 4.3 and include abnormal habituation of cortical responses and decreased visual acuity. The results, summarized in Figure 4.3, show that NGF allows a normal or nearly normal development in dark-reared animals with respect to the tested parameters. In particular, Figure 4.3 shows that development of visual acuity is normal in dark-reared rats treated with NGF.

Concurrent synaptogenesis in the cortical mantle

Togenesis Studies in human infants show that virtually all cortical functions, including language, have anlage in early infancy and do not arise de novo at a late stage of maturation. In humans, evoked activity in response to the maternal voice is present even before birth (Lecanuet and Granier-Deferre, 1993), and the development of visual acuity and depth perception begins in newborn infants (Teller, 1997, and chapter 6 of this volume). Human infants also evidence expectations based on auditory and visual stimuli that depend on the association cortex. Human infants also show competence to represent numerical entities, including action sequences

The Retina and Prosthetic Devices

Photoreceptor loss from diseases such as retinitis pigmentosa (RP) and age-related macular degeneration (AMD) are the leading cause of legal blindness. Despite near-total loss of photoreceptors in these diseases, there is relative preservation of the other retinal neurons. By stimulating the remaining functional retinal layers, it may be possible to restore visual perception. In other diseases, this approach may not be practical. For example, in glaucoma (high intraocular pressure with optic nerve damage), the ganglion cells are primarily damaged. In diseases such as retinopathy of prematurity, diabetic retinopathy, and vascular diseases of the retina, all the layers are affected. In these diseases, it is highly unlikely that electrical stimulation of the retina can restore visual function, and other approaches such as retinal transplantation or electrical stimulation of the visual cortex should be investigated.

The use of nutrition panels

If we focus on the preferences expressed by those who participated in the survey for presentation of the nutrition panel and the aspects and terms of the current format they found difficult to understand the easiest to use were those that were clear and easy to read e.g. large print good for poor eyesight (50 ) good layout (general) e.g. simple, clear, neat, in order (in a column) (22 ) easy to understand (9 ) (other points were use of highlighting or bold print distinction between medium and high showing value per 100 g familiar used to it seen most often.) The most difficult to use were those with poor layout e.g. crammed together, jumbled, a muddle, words run together, cluttered (41 ) difficult to read indistinct small print (34 ) not tabulated nor itemised, not in columns (9 ) hard to pick out a particular piece of information (4 ).

Methylisocyanate and the tragedy of Bhopal

This moving poem is by a survivor of the terrible industrial accident in the Indian city of Bhopal in December 1984. Just after midnight on 2 December 1984, a large cloud of vapour leaked from a factory in Bhopal, spreading out over a nearby area of shanty town, where thousands of inhabitants were sleeping. In all, between 30 and 40 tonnes of this toxic chemical were released. Many died of asphyxiation as the highly irritant gas damaged their lungs, causing fluid to accumulate, which effectively drowned them. Others survived the initial onslaught of the vapour but succumbed later to the combined effects of damage to the lung and to other organs (see box). Those who survived did not necessarily recover completely, as they continued to suffer from lung disease and blindness or poor eyesight, as well as impaired immune systems and reproductive problems. The irritant nature of the chemical meant that it attacked membranes in the lungs and eyes and the skin.

Mechanisms of visual development

Optics and Accommodation The optical quality of the primate eye is excellent at birth, and places no major limitations on visual acuity or other visual functions (see Banks and Bennett, 1988, for a review). Moreover, the development of accommodation (the capacity of the lens of the eye to change its focal length in order to focus on objects at varying distances) provides an example of an immaturity that is probably not a critical immaturity. Newborn infants typically do not accommodate differentially for objects at different distances (Haynes, White, and Held, 1965), and it might be thought that the resulting blur in the retinal image would contribute to their reduced grating acuity. However, the opposite direction of causality is more likely. That is, if the infant's visual system cannot process high spatial frequencies (see below), the infant has no need to accommodate, and no basis for generating signals that would lead to changes in accommodation.

Summary and conclusions

One final question can be raised Why do vision and the visual system bootstrap themselves in the particular sequence that they do Why is a visual world with poor visual acuity and contrast sensitivity, poor sensitivity to color differences, and no stereopsis sufficient for young infants, while excellent representation of the temporal properties of stimuli is apparently required Which of these developmental time courses are direct products of natural selection acting on infant behavior, and which are accidental consequences of other evolutionary pressures It is easy to speculate that natural selection favors infants who perceive depth and distance before they can crawl but beyond this, we know little about the reasons for the pattern of emergence of different visual functions over the course of infancy. ACKNOWLEDGMENTS Portions of this paper are excerpted with permission from Teller, D. Y., 1997. First glances The vision of infants. The Friedenwald Lecture. Investigative Ophthalmology...

Alternative and complementary therapy research needs open minds

Some publications about trials in homeopathy show an uncanny resemblance to the penicillin story. Stacey (1991) says it is a failure of Western scientific models to understand anything of alternative medicine, not just individual myopia, that gives rise to the refusal to accept that alternative medicine works.

Developmental specificity of visual functions in humans

The retina) is more affected by visual deprivation than is development of the W- and X-cell pathways (Sherman and Spear, 1982). Investigators have also reported that the effects of congenital visual deprivation (due to cataracts) are more pronounced on peripheral than foveal vision (and by implication on the dorsal pathway) (Mioche and Perenin, 1986 Bowering et al., 1997). Moreover, in developmental disabilities including dyslexia, specific language impairment, and Williams syndrome, visual deficits are more pronounced for dorsal than ventral visual pathway functions (Lovegrove, Garzia, and Nicholson, 1990 Eden et al., 1996 Atkinson et al., 1997). An additional hypothesis that may account for the greater effects on peripheral vision is that in development the effects of deprivation and enhancement are equivalent within all cortical regions. Those areas with less extent to begin with (e.g., MT, peripheral visual representations) would display the largest proportional effects of both...

Challenges for Accurate Assessment

France (1992) provides a detailed account of the visual deficits of children with Down syndrome. He followed a group of 90 children and reported that 49 had visual acuity deficits, with myopia being the most common. He also documented oculomotor imbalance in over 40 of the children, convergent strabismus accounting for the majority of these cases. In the majority of these cases only glasses were required to achieve normal vision. The message here is to make sure the children can see the stimuli during testing.

Programmable RP Molding

Saul Griffith, while a graduate student at MIT, developed a programmable printer for eyeglass lenses. This is a rapid prototype device that curves a membrane to form a mold cavity. The idea was to solve the problem of stocking an inventory of costly or inappropriate eyeglass lenses to serve the vision care needs of millions in the developing world who cannot afford standard prescription ground eyeglasses. A company, Low Cost Eyeglasses, has been formed to make this solution available to those who need it (

Connective tissueactivating peptide III ctap iii

Types express more than one connexin. Connexin phospho-rylation has been implicated in connexin assembly, gap junction turnover and responses to tumour promoters and oncogenes. Connexin43 (Cx43), the most widely expressed and abundant gap junction protein, can be phosphorylated at several different serine and tyrosine residues. Mutations in connexin genes are associated with peripheral neuropathies, cardiovascular diseases, dermatological diseases, hereditary deafness and cataract. See connexon.

Objective Correction Collar

Microscope eyepieces increase the magnification of the microscope image and position the image so that it can be seen by each eye. Eyepieces may also be engineered with a variety of features, including those that correct chromatic aberrations (C, K), those that provide a wide field of view (WF), and those that allow viewing from a greater than standard distance (H) (thus allowing the microscopist to wear corrective eyeglasses) (5). Most eyepieces are adjustable so that the focus characteristics of each eye can be optimized for the individual viewing an image. This allows the images at each eyepiece to be brought into simultaneous focus, permitting individuals with vision deficits to be able to use the microscope without the need for corrective lenses. Finally, cross-hairs may also be present in an eyepiece to provide an indication of the image focus at the microscope compared to the image focus at a photographic camera.

Intracranial EEG Investigation in Neocortical Epilepsy

Summary Intracranial EEG Investigation in Neocortical Epilepsy, a chapter in Neocortical Epilepsies, begins by discussing problems and pitfalls in the electroencephalographic (EEG) localization of neocortical epilepsy, focusing on (1) undersampling and nearsightedness of recording electrodes (2) large epileptogenic zones restricted to neocortical structures, involving neocortical as well as deep sulcal or mesial structures, and bilobar or multilobar distribution (3) rapid seizure propagation (4) seizure generator located in a clinically silent area and (5) low incidence of specific neuroimaging abnormalities. The next section focuses on coregistration with intracerebral and epidural

Specializing In Two Tiny Organs

The eye and its supporting cast make up perhaps the most highly specialized and complicated organ system in existence. Approximately 35 of all the sensory input into the brain is made up by the left and right optic nerve, and roughly 65 of all intracranial disease processes have ophthalmologic manifestations.1 A OPHTHALMOLOGIST One of the most important things for medical students to determine when considering ophthalmology as a career is whether or not they would be happy specializing in only one region of the body. This is not to say that there are not vast arrays of disease processes that have ophthalmic manifestations in fact quite the opposite is true. Rather, the examination skills, diagnostic tools and surgical procedures you learn and use as an ophthalmologist involve a small area of the body and one highly specialized organ system. Unlike in surgical specialties, the ophthalmologists' surgical field is typically measured in millimeters. The lids and skin surrounding the eye...

Performing Surgery On The

Like their colleagues in otolaryngology, ophthalmologists practice both medicine and surgery. To be a good surgeon of the eye and its related structures, you must have excellent hand-eye coordination and fine motor skills. Much of the precise, targeted surgery occurs behind the lenses of a microscope and with the use of a high-powered laser. It is a different kind of surgery than in other subspecialties cleaner, shorter, more controlled, with less worry about bleeding and less of a need to suture fascia or cauterize blood vessels. Like most surgeons, ophthalmologists are action-oriented physicians who like to see fast results. In the operating room, they demand as much attention to detail as any other surgeon. In this specialty, all results of surgery are permanent and usually cannot be reversed. Thus, care, precision, and patience are key components to being a good oph-thalmologic surgeon. Most ophthalmologists perform refractive surgery such as LASIK, in which they reshape a...

Fellowships And Subspecialty Training

It might be surprising that a field as seemingly specialized as ophthalmology could have several fellowship opportunities to specialize even further, but this is the reality. This extra training allows physicians to treat and operate on very different disease processes using equally diverse procedures. Ophthalmology fellowships are generally 1- to 2-year endeavors. Unlike many fields within medicine, completing fellowship training often does not mean limiting yourself only to that subspecialty area of practice. Many ophthalmologists who have completed fellowships choose to integrate that area of expertise into their practice of general ophthalmology.

Cornea and External Disease

Residency in ophthalmology requires 4 years of postgraduate training. There are currently 122 accredited programs, most of which are very small. It requires 1 internship year (internal medicine, surgery, or transitional) plus 3 years of ophthalmology training. The structure of individual programs varies greatly but must meet the basic requirements set by the American Academy of Ophthalmology. Some programs utilize full-time faculty for teaching while others provide instruction through community-based ophthalmologists as part-time or volunteer faculty. Usually the first year of residency is spent in the clinic evaluating a wide variety of patients, mastering examination skills, and seeing consults within the medical center. The resident may also perform minor surgical procedures during this year. The second and third years involve rotations through subspecialties like pediatrics and oculoplastics, as well as much more time spent in the operating room, assisting with surgery and then...

Box 243 Pharmacogenetics

The emerging field of pharmacogenomics involves the study of human genetic differences that contribute to differences in reactions to drugs. In some cases, such as malignant hyperthermia, the variability may take the form of an iatrogenic, or drug-induced, illness. In other cases, there may be a difference in response to the drug, as has been seen in the cases of some asthma sufferers who do not respond to an asthma medication because they have a mutation that changes the receptor protein that binds the drug. One form of glaucoma results when individuals who are susceptible to the effects of corticosteroids are exposed to dexamethasone, which causes elevated intraocular pressure that will lead to glaucoma if left untreated (see Figure 24.1). In addition, some patients do not respond to one or more of the glaucoma medications they are given, possibly because of genetic differences in the body's ability to react to the drug. Often, the real array of variability in response to a drug is...

Ophthalmic Plastic Surgery

Do you have an eye for beauty Those trained in oculoplastics blend ophthalmology and plastic surgery in the treatment of the orbit, lid, nasolacrimal system, brow, and upper face. Oculoplastic surgeons remove the eye in cases of extensive trauma, intractable and severe eye pain, and destruction secondary to neoplastic or inflammatory processes. They reconstruct the orbit, lids, and upper face in cases of tumor, trauma, or other local processes, and perform cosmetic surgeries such as orbital wall decompression. They are also trained in the use of radiation and chemotherapy. Optic nerve fenestration, one of the more interesting procedures, helps young patients suffering from pseudotumor cerebri, a condition in which elevated intracranial pressure (for unclear reasons) causes vision loss. In this fascinating procedure, the oculoplastic surgeon dissects back to the optic nerve, rotates the eye laterally, and, rapidly enough so as to avoid damage due to the lack of blood flow caused by...

About The Contributor

Andrew Schwartz is a resident in ophthalmology at The Mount Sinai Medical Center in New York City. After receiving his undergraduate degree from Tufts University, he attended medical school at Loyola University Chicago Stritch School of Medicine. Dr. Schwartz is particularly interested in orbital trauma and other disease processes affecting the orbit. In his free time, he enjoys tennis and running, as well as playing and listening to music. Dr. Schwartz would like to thank his father and grandfather (both pe-

From Ent To Hns A Brief History Of Otolaryngology

Most medical students probably do not realize that otolaryngology is one of the oldest formally organized specialties within medicine. In 1896, a group of practicing ophthalmologists and otolaryngologists conducted a 2-day program of scientific presentations in Kansas City, which led to the formation of the Western Ophthalmological, Otological, Laryngological and Rhinological Association. This association was the genesis of the very first specialty board organization in the United States, the American Board of Ophthalmology, formed in 1917, and its successor, the American Board of Otolaryngology, formed in 1924.

Mechanistic Toxicogenomics

This is used to improve human risk assessment by expanding accessible interspecies biomarkers of toxicity and improving the understanding of interspecies similarities and differences. A case example was presented involving identification of gene expression alterations in the rat lens associated with formation of cataracts, following administration of a 5-lipoxygenase inhibitor. The pattern of gene expression confirmed that the compound inhibited the synthesis of cholesterol and that lens crystalline structural proteins were targets of drug cataractogenesis. Further studies are needed to investigate interspecies relevance of the mechanistic-based markers of the onset and progression of cataracts.

Measurement Techniques and Instrumentation

Experiments were performed under animal care and experimental guidelines that conformed to those set by the National Institutes of Health. Only a brief description of the animal preparation, maintenance, and surgical procedures is given here because they have been fully described elsewhere (Nordhausen et al., 1996 Warren et al., 2001). Felines were inducted with Telazol, cannulated, intubated, and their heads immobilized. The animals were artificially ventilated and anesthesia was maintained with halothane (approximately 0.8 during recording). The visual cortex was exposed by a 1- to 2-cm-diameter craniotomy and the dura reflected. Paralysis was established with pancuronium bromide (0.1 mg kg h, i.v.). The pupils were dilated, the nictitating membranes were retracted, and the eyelids were sutured open. Gas-permeable contact lenses were placed in each eye to protect the corneas. The retinas were back-refracted onto a tangent screen and the locations of retinal landmarks were recorded...

National Association for the Visually Handicapped

The only nonprofit health agency in the world solely dedicated to providing assistance to those with partial vision loss (the hard of seeing). The association works with millions of people worldwide coping with difficulties of vision impairment and providing anything from large-print books to the latest information on a particular condition.

Necrotizing enterocolitis

Often young nearsighted children do not realize that they have a visual problem. symptoms include squinting, holding the head at an unusual angle, eye rubbing, sitting too close to the TV, and clumsiness. Many parents do not notice the problem until the child starts school, when it quickly becomes apparent that there are problems in seeing the blackboard. Many parents first discover a problem during a school vision screening. Correction for nearsightedness includes wearing glasses or contact lenses. Because a child's eyes grow and change quickly during the first seven years of life, youngsters this age may need vision checks every six months. Because contact lens require more difficult care, they are rarely prescribed for young children.

Neurocutaneous syndromes

Neurofibromatosis (NF) One of the most common neurocutaneous syndromes that primarily affects the growth and development of nerve cells, causing tumors or neurofibromas that produce skin changes, bone deformities, eye problems, and other complications, especially in the brain. In 1882 neurofibromatosis (NF) was first described in medical literature by Dr. Friedrich von Recklinghausen, and the disease was known as Von Recklinghausen's disease for many years. NF affects more than 100,000 Americans, making this condition more common than cystic fibrosis, hereditary muscular dystrophy, Huntington's disease, and tay-sachs disease combined.

Mutation Type And Disease Severity

However, for many genes, such as the MYOC glaucoma gene, we cannot make simple generalizations. Although many different MYOC missense mutations cause a very severe autosomal dominant form of glaucoma in children or young adults, some other missense mutations in MYOC do not cause glaucoma at all, even though they also change the amino acid and in some cases are located in regions where other missense mutations have been found to cause disease. A nonsense mutation at codon 368 in one copy of the MYOC glaucoma gene causes disease that is milder and starts later than the disease caused by many of the missense mutations, and another nonsense mutation at codon 46 was found in someone older who does not have glaucoma at all.

Variable Expressivity

We use the phrase variable expressivity to refer to the situation in which different individuals with the same disease-causing mutation show quantitative or qualitative differences in the severity of the trait. Let's take the example of a family in which everyone affected with glaucoma has a Val426Phe MYOC mutation. A total of twenty-two members of this family have glaucoma caused by the Val426Phe mutation. The average age at which glaucoma was diagnosed in this family is twenty-six years of age, which is decades earlier than the age at which the common forms of glaucoma usually turn up. One of the most obvious signs of variable expressivity in this family is the great variation in the age at which the disease first manifests itself. The earliest age at which anyone was diagnosed was age sixteen, and the latest diagnosis was at age forty-six. One individual with the Val426Phe mutation still had not developed the disease by the time she was sixty, although...

Surgical Trabeculectomy

Visualize (have the patient look way down). There may be mild corneal edema and or folds (1+). There is generally a marked anterior chamber reaction of 2+ to 3+. You should also note the chamber depth. Immediately after surgery, it is normal for the chamber to be shallow. Note if a hyphema is present as well as the pupil size and shape. If the trabeculectomy was combined with cataract surgery, see also the section on cataracts. As the eye heals, continue to monitor the bleb. It should be elevated and blisterlike (Figure 7-6). If not, be sure to note that it is flat. Sometimes a bleb becomes lumpy, cystic, or encapsulated in appearance. Be sure to note if the bleb begins to encroach onto the cornea. Be on the alert for dellen. Watch the AC for depth and inflammation as well as for formation of anterior or posterior synechia. Check the lens for formation of a cataract.

Laser Trabeculoplasty

There may be very mild (1+) conjunctival injection following a laser trabeculoplasty. You may also note the presence of some episcleral congestion. The cornea may evidence some superficial punctate erosions secondary to the contact lens used to direct the laser beam. Transient corneal epithelial burns may also be present. Otherwise, the cornea is generally quiet. Check for anterior chamber reaction, which is usually mild (1+ to 2+). In rare cases, a hyphema may be present. Note the pupil shape and size, and watch for formation of peripheral anterior synechiae.

Subarachnoid hemorrhage 299

Sturge-Weber Foundation A support group for those with sturge-weber syndrome and their families, concerned professionals, and supporters the group serves as an information clearinghouse on the syndrome, which is a congenital neurological disorder characterized by facial port-wine stains, seizures, glaucoma, and loss of motor control. The group also maintains a speakers' bureau, compiles statistics, and funds research. Founded in 1986, the group publishes a quarterly newsletter. For address, see Appendix I. In the brain, excessive blood vessel growth develops on the back region of the brain, on the same side as the port-wine stain. These growths, called angiomas, often lead to seizures that usually begin by age one. The convulsions usually appear on the side of the body opposite the port-wine stain, and vary in severity. A weakening or loss of the use of one side of the body opposite the port-wine stain also may develop. Developmental delay of movement and cognitive skills may also...

Retina and Vitreous Scleral Buckle Retinal Detachment Repair

One of the risks in retinal detachment repair is the occurrence of anterior segment necrosis, which occurs rarely during the late postoperative course. The slit lamp findings in this complication include marked chemosis corneal edema striae white flakes in the anterior chamber or on the lens large keratitic precipitates an irregular, dilated pupil iris atrophy posterior synechiae and cataract formation.

Vitrectomy or Fluid Gas Exchange

Conjunctival edema, injection, and subconjunctival hemorrhage are normal findings. As with a scleral buckle, the conjunctival incision site is at the limbus. The corneal epithelium may show some punctate staining from exposure. The amount of inflammation in the AC is the most important slit lamp finding. Flare is normal, but cells are generally less visible. The anterior chamber reaction may be quite marked in diabetics. There should not be an hypopyon. Examine the lens for possible cataract formation. (Contact with the lens by the gas markedly increases the chances for cataract development.)

Cellular Origins Of The Electroretinogram

The ionic fluxes described above give rise to radial currents that underlie various components of the electroretinogram (ERG), a light-evoked transretinal potential widely used as a noninvasive, objective test of retinal function in the differential diagnosis of visual disorders (cf. Goodman and Ripps, 1960 Ripps, 1982 Hood and Birch, 1990 Berson, 1993). Whether recorded across the retina, i.e., between electrodes in the vitreous and at the basal surface of the RPE, or with a contact lens electrode on the cornea of the intact eye, the ERG response evoked by the onset of illumination consists primarily of three readily detectable components the a-, b-, and c-waves. The variation in response polarity and time course indicate that this complex waveform reflects the summation of potentials arising from different sources. Each component is itself a composite derived from more than one cellular source.

The safety of microwaveheated food

The practical and achievable limit of 10mW cm2 is justified because the microwaves that are used are identical with those used in therapy. (For therapeutic effects the energy density must be well above a level of 100mW cm2.) There are numerous studies to determine damage thresholds and it has been observed that no permanent effects occur at levels below 100mW cm2. For a critical organ, the eye, it was observed that cataract formation may occur at 150mW cm2 when the microwaves are applied for more than 90 minutes. Within certain limits the body can absorb energy including microwaves and compensate for the temperature increase easily by removing excessive heat by means of blood flow. There are certain avascular structures in the body that may have a relatively poor heat exchange this is possibly true for testicles and temporary sterility has been reported after microwave exposure. The energy flow from the sun may be considered for comparison on a sunny day in summer the infrared portion...

New Hampshire Site Visit November 2001

Because of the limited nature of the public health infrastructure of the Twin Rivers area, CCNTR, local health officers, and the community have creatively assembled a public health system that draws on the locally available public health expertise that is available but also capitalizes on community resources and skills. The committee heard about the potential implications posed by this specific scenario to national-level attempts to standardize local public health infrastructures and credentialing public health workers. Although the Twin Rivers community leaders present at the site visit expressed a clear vision of quality public health services, they expressed some

Box 345 Organizations

For instance, if a mutation is associated with the trait but does not seem to be an outright cause of the trait, researchers may elect to continue more investigation of the gene before making testing available for general clinical use so that they do not end up putting uninterpretable results into the hands of doctors and patients who will then not know what to do with information that is ambiguous. For instance, there is a sequence variant in the optineurin gene that is found more frequently in people with glaucoma than in people who do not have glaucoma. However, there are many people with glaucoma who do not have it, and many people who have it who do not have the disease. For now, it is considered a risk factor something that tells you that you have a higher chance of the disease than the general population without indicating that you are certain to develop the disease. Until more is understood about what role this sequence variant is playing, further research is needed and...

Oakland Site Visit October 2001

The services provided include primary medical care dental, mental, and eye care clinic- and community-based health education nutrition services social services and off-site inpatient care. Asian Health Services has been serving the community since 1974 at three locations and with 120 staff. Its services include clinical services like maternal and child health HIV testing, counseling, and care adolescent, adult, and elderly care and urgent care. It provides health education services on topics ranging from family planning to disease prevention (cancer and HIV AIDS) and women's health.

Ocular route for topical delivery

Cyclosporin A is another peptide that may have a role in inhibiting the rejection of corneal grafts. Administration of 2 cyclosporin A in olive oil as eyedrops has been reported to result in a high concentration of the drug in the cornea and conjunctiva, but no intraocular penetration was observed. However, penetration into intraocular tissues can be achieved by formulation changes.203 204 Tissue plasminogen activator (tPA) is another protein that may find topical use to achieve clot lysis in the eye. Though tPA is approved by the FDA for lysis of thrombi in coronary arteries, its use in ophthalmology represents a nonapproved indication for an approved drug. In a study with ten patients who developed complications that threatened the successful outcome of anterior segment surgery, tPA completely or almost completely dissolved clots within 30 min to a few hours after tPA injection, and 100 resolution of fibrin and blood clots was observed at the first follow-up.205 Other peptides and...

Sexually transmitted disease 447

At the minimum, these diseases cause discomfort. Left untreated, some STDs can cause serious long-term health problems. For example, gonorrhea and chlamydial infections can cause pelvic inflammatory disease, infertility, and ectopic pregnancy. Several common STDs adversely affect pregnancy, resulting in spontaneous abortion, stillbirth, and premature delivery. Genital infections due to human papillomavirus are associated with cervical cancer, one of the most common cancers in women throughout the world today. Moreover a pregnant woman can pass an infection to her baby. Infections in newborns include syphilis, herpes, gonococcal conjunctivitis (an eye disease that can lead to blindness), and chlamydial pneumonia, an infection of the lungs that can develop into a chronic respiratory disease.

Box 348 The Option To Not Test

Even a brief conversation with Jill shows her to be expressive and intelligent, with her striking prettiness often lit up by warmth and sympathy and humor that have to have been assets in her nursing career. However, when Jill was growing up, people who did not know her well sometimes decided that she was a bit stuck-up or standoffish. If you were to meet her, you would wonder how anyone could think her manner anything but friendly. That is, you might wonder, unless you looked down and saw her constant canine companion, a beautiful yellow lab wearing a sign saying, Please do not pet me, I am working. Jill was born deaf and as a teenager began losing her sight. She was mainstreamed in the public school system, learning to speak words she could not hear and to hear spoken language through a combination of lip-reading and other cues. She was adept at carrying on a conversation with someone sitting across from her at the lunch table or standing and talking to her in the hall. However, if...

ISO 10993 Biological Evaluation of Medical Devices

Devices communicating with intact mucosal membranes. Examples include contact lenses, urinary catheters, intravaginal and intraintestinal devices (stomach tubes, sigmoidoscopes, colonoscopes, gastroscopes), endotracheal tubes, bronchoscopes, dental prostheses, orthodontic devices, and IUDs.

The Line That Cant Be Crossed

The scene on the screen in the conference room looked just like a home video, a movie showing a beautiful briard dog named Lancelot walking into a dimly lit room. The place seemed a bit crowded, with disarranged furniture scattered about. The audience in the conference room watched, spellbound, almost holding their breaths, as the dog made his way through the room, carefully avoiding objects as he swung his head around in an odd manner to scan the area ahead of him with his right eye. He daintily picked his way through the obstacle course, the film stopped, the lights came up, and a few quiet spontaneous cheers could be heard over the applause that broke out around the room. Several of the rational, objective researchers in the room had lumps in their throats as they listened to the conclusion to the presentation. Gene therapy treatment of Lancelot's right eye when he was four months old had effectively cured a canine model of Leber congenital amaurosis, a severe form of early...

It is not a sensory substitution

After the event, it is clear that it is the reverse which would have been astonishing. Meaning or emotional significance are not things that are already there, in the world, just waiting to be picked up like a piece of information. Here again, by the failure of its initial ambition, the device of Bach y Rita provides a crucial empirical proof An isolated subject cannot attribute an existential meaning to objects and events that he perceives simply on the basis of a new perception. Does it follow that something essential is lacking in these devices Unable to give a content to the perception (color, value), they demonstrate what distinguishes natural perception from a simple capacity to discriminate and categorize. There is a striking similarity between these observations, and reports of the absence of emotion and meaning felt by persons blind from birth who recover sight by removal of a cataract. In other words, it is not the principle of sensory substitution as such which is...

Not Being Easily Understood By People With Normal Hearing

A further problem can be physical appearance. After my initial operations I was left with gross unilateral facial palsy. The grafted nerve took almost two years to function adequately but I still have significant facial nerve and eye problems. This undoubtedly lowers confidence and hinders developing relationships.

The reading interface

From this point of view, the situation is not very different for a reader with a visual impairment or for a sighted reader, neither being able to read the electronic document directly with the eyes. For a sighted reader, the reading interface is based on a screen display, a keyboard and a mouse, while a blind person will use a keyboard and a braille refreshable display or a speech output. Both of them will need a set of functions for navigating through the document, marking pages or sections, or even annotating it. In some situations, sighted users will need non visual interfaces as well, when driving a car, or consulting an information server over the phone, for instance.

Associated Problems Corneal Hypoxia

Contact Lens Staining Patterns

Corneal hypoxia (lack of oxygen) in rigid lenses often causes an area of edema that is central, rather than diffuse as in soft lenses. This central area is round or oval (in the case of astigmatism), about 2.00 to 4.00 mm across, and grayish white. Draw or describe and grade any edema that is present. The edema becomes more dense as the condition worsens and may eventually be visible without the slit lamp. The problem may also be accompanied by superficial punctate corneal staining (see Corneal Staining below). Figure 9-12. Common types of rigid lens staining. Top left Diffuse punctate staining. Usually chemical or environmental in origin. Often related to solution sensitivity. Top center Apical staining. Often due to poor lens cornea relationship. Common in keratoconus patients. Top right Overwear stain (epithelial erosion). Middle left 3 00 and 9 00 staining. Attributed to lid gap, poor blink pattern, mechanical trauma. Desiccation occurs in areas adjacent to lens edge at...

Treatment of systemic manifestations

Formally been shown for eye disease (Hamuryudan et al., 1997) and in the management of pulmonary artery aneurysms (Hamuryudan et al., 2004). Azathioprine has been formally shown that to be effective in controlling eye disease and some of the extraocular manifestations including skin-mucosa disease, in a double-blind placebo controlled study. Recommended dose of azathioprine is 2.5mg kg day (Yazici et al., 1990). We commonly treat severe eye disease with a combination of azathioprin and cyclosporin A mainly using the latter as a remisson inducing agent and the former as the maintenance drug (Yazici et al., 1999). Infliximab, in uncontrolled studies, has been shown to have a beneficial effect in BS not only in eye disease (Sfikakis, 2002 Ohno et al., 2004 Lindstedt et al., 2005) but on the extraocular manifestations as well (Haugeberg et al., 2004 Sarwar et al., 2005). In brief within the last decades substantial progress has been made in managing BS. Patients with eye disease,...

Movement and Centration

Reverse Testicular Atrophy

A rigid lens is smaller than a soft lens and, thus, will not cover the cornea. The old PMMA hard contact lenses were designed to have an interpalpebral fit. That is, the centered lens lies entirely between the lids. The more modern method of fitting gas permeable lenses (which are larger than PMMA contacts) is the alignment fit, where the upper third of the lens stays under the upper lid (Figure 9-7). If the fluorescein reflex is bright green and the tear layer is thick, there is clearance between the contact lens and the cornea. A faint green reflex and a thin tear layer indicate minimum clearance. If the reflex appears black and there is no tear layer, then the lens is touching the cornea. In a good fit, a thin film of dye will be evenly spread under the entire lens, with slight pooling at the periphery. If the patient has astigmatism, you might see a band of dye running horizontally or vertically. A loose (flat) lens will show a central absence of dye and a pooling around the edge...

Posterior Chamber Intraocular Lens Implant

When a cataract is removed, the posterior lens capsule is often left in place to support a posterior IOL. If it is clear, as it should be, you may barely be able to see it. When you direct the beam straight-on and directly through the pupil, the capsule should light up evenly without any opacities or irregularities. Documentation capsule clear

Inherited Syndromes of Low LDLC Abetalipoproteinemia

Abetalipoproteinemia is a rare autosomal recessive disease caused by mutations in the gene encoding microsomal transfer protein (MTP) (11), a protein that transfers lipids to nascent chylomicrons and VLDL in the intestine and liver, respectively. Plasma levels of cholesterol and triglyceride are extremely low in this disorder, and no chylomicrons, VLDL, LDL, or apoB are detectable in plasma (12). Obligate heterozygotes have normal plasma lipid and apoB levels. Abetalipoproteinemia usually presents in childhood with diarrhea and failure to thrive and is characterized clinically by fat malabsorption, spinocerebellar degeneration, pigmented retinopathy, and acanthocy-tosis. The initial neurological manifestations are loss of deep tendon reflexes, followed by decreased distal lower extremity vibratory and proprioceptive sense, dysmetria, ataxia, and the development of a spastic gait, often by the third or fourth decade. Patients with abetalipoproteinemia also develop a progressive...

The Approach Look For The Rare But Remember The Ordinary

In this chapter I provide suggestions for medical-family history queries for the following broad categories of disease birth anomalies (Section 4.2), hearing loss (Section 4.3), visual impairment (Section 4.4), mental retardation (Section 4.5), autism (Section 4.6), neurological conditions (Section 4.7), seizures (Section 4.8), dementia (Section 4.9), mental illness (Section 4.10), cardiac disease (Section 4.11), chronic respiratory disease (Section 4.12), renal disorders (Section 4.13), short stature (Section 4.14), diabetes (Section 4.15), reproductive loss and infertility (Section 4.16), and sudden infant death (Section 4.17). Family history markers for identifying individuals with an inherited susceptibility to cancer are discussed in Chapter 5. The decision to include these general groupings of disease in this chapter is based on my experience with some of the questions people have asked me most frequently about disorders in their family. Cataracts at a young age

Adolescent Female with Tremor Depression and Hepatitis

The slightly low ceruloplasmin level in the setting of elevated transaminases and neurologic symptoms raised the suspicion of hepatolenticular degeneration (Wilson's disease). A serum copper was obtained but at 171 mg dL (26.9 mmol L) was within the normal range of 60-190 (9.4-29.9). A more careful eye examination showed a golden brown band of pigment encircling the posterior cornea near the limbus of both eyes. An ophthalmologist performed a slit-lamp examination confirming the presence of Kayser-Fleischer rings. An MRI of the brain with T2 weighting demonstrated possible hyperintensity of the basal ganglia, a finding often seen in Wilson's disease. A baseline 24-hour urine collection was assayed for copper to further support the presumptive diagnosis of Wilson's disease, and a complete urine collection was documented by volume (840 mL day) and urine creatinine (0.9 g day). Baseline urinary copper excretion was elevated at 154 mg day (2.43 mmol day) (reference range, < 40-100 <...

BDNF overexpression accelerates the functional development of the visual cortex

Thyroid Muscles Ultrasound

This accelerated development of inhibition is paralleled by changes in the functional development of the visual system there is precocious development of visual acuity with respect to the wild type and precocious closure of the critical period, possibly accompanied by precocious opening. Figure 4.8 clearly illustrates that in BDNF mice there is a shift toward younger ages of the curve describing the developmental time course of visual acuity and of the curve describing the decline of monocular deprivation effective- Figure 4.8. Critical periods for monocular deprivation and development of visual acuity are reported for wild-type mice, A and transgenic mice with precocious expression of BDNF, B. For BDNF mice, both the critical period (dotted line) and the visual acuity (solid Figure 4.8. Critical periods for monocular deprivation and development of visual acuity are reported for wild-type mice, A and transgenic mice with precocious expression of BDNF, B. For BDNF mice, both the...

Anterior Chamber Aqueous and Angle

Slit Lamp Angle Estimation

The aqueous that fills the anterior chamber is constantly being formed and drained out. The aqueous drainage area is found in the angle, the area formed where the posterior corneal surface meets the anterior iris root. (The angle itself cannot be viewed directly unless a gonio lens is used.) This dynamic creates a pressure within the eye, the IOP. Average IOP is around 15, ranging from 8 to 21. (Opinions vary as to what is normal.) IOP is measured using a tonometer, which may be attached to the slit lamp. If the IOP is abnormally high and continues to be high, the optic nerve may be damaged, which, in turn, can reduce the visual field. This condition is called glaucoma. The depth of the anterior chamber is clinically significant. In a shallow chamber, the dilated iris may bunch up and block off the angle. This covers the aqueous drainage system, and the pressure of the stagnant (and continually forming) aqueous begins to build up. The pressure causes corneal edema (swelling that...

Arteriosclerosis arcus senilis

Asthma conjunctivitis, cataract (secondary to corticosteroid treatment). Bell's Palsy incomplete or absent lid closure, exposure keratitis. craniofacial syndromes exophthalmus, nystagmus, exposure keratitis, coloboma. diabetes xanthelasma, corneal wrinkles, rubeosis of iris, loss of iris pigment, cataract, asteroid hyalosis. Downs Syndrome nystagmus, epicanthal folds, keratoconus, iris spots, Brushfield's spots (gray or white spots around the edge of the iris), cataract. eczema lid crusting, scaling, and oozing (blepharitis) conjunctivitis conjunctival thickening congestion of conjunctival blood vessels dry eye keratoconus cataract. emphysema cataract (secondary to corticosteroid treatment). endocarditis nystagmus, tiny red dots on conjunctiva, anisocoria, iritis. facial deformity syndromes microphthalmos, down-sloping lid slant, nystagmus, lower lid coloboma, dermoid cysts of the globe, cataract.

Differential Diagnosis

Have a significantly increased risk for coronary artery disease. Because of the decreased content of cholesteryl esters in lipoproteins, they do form abnormal-shaped lipoproteins, which accumulate in the glomerulus, causing renal insufficiency. Heterozygous patients with only a partial deficiency of LCAT, which is sometimes called Fish-eye disease, usually just have corneal opacities and only have a modest decrease in HDL-C.

The Consequences Of A Magno System Deficit

In an earlier review, Stein and Walsh (1997) argued that Slight impairments of mLGN (magnocellular laminae of the LGN) performance or organization might multiply up to greater deficits in PPC (posterior parietal cortex) function. The PPC is known to be important for normal eye movement control, visuo-spatial attention and peripheral vision all important components of reading (p. 149).

Clinical manifestations

The tear film plays an essential role in promoting ocular surface integrity, defending against micro-bial challenge and preventing visual acuity. These functions, in turn, are extremely dependent upon the composition and stability of the tear-film structure. This includes an underlying mucin foundation (derived from globet cells and conjunctival- and corneal epithelial cells), a middle aqueous component (secreted primarily by lachrymal gland acinar and ductal epithelial cells) and an overlying lipid layer (originating from the meibomian glands). In

The Chromosomal House of Horrors

Another genetic disorder recently mapped to chromosome 8 causes individuals to senesce and die early, usually by age fifty. The gene responsible for Werner syndrome encodes a defective DNA helicase enzyme that in normal form appears to play a cellular role in the repair of DNA damages. The mutation leading to Werner syndrome has devastating effects patients in their thirties typically show pronounced symptoms of old age, such as cataracts, osteoporosis, and heart disease. The Werner syndrome gene provides an unusually clear example of direct genetic control over the aging phenomenon itself.

Issues in teaching and learning braille

The teaching of braille to the newly-blinded older learners who were printreaders before the onset of their visual impairment is usually carried out as part of the wider rehabilitation process. For some people, the acquisition of specific new skills, such as braille, and the re-gaining of some degree of independent mobility, can contribute significantly to their overall rehabilitation. One of the problems for teachers is that the teaching of braille cannot be done on a whole class or group basis. Unlike print symbols, braille symbols cannot be put on the equivalent of a blackboard or overhead projector transparency so that their shapes and meanings can be explained to 10 or 20 learners simultaneously. Braille has to be taught on a one-to-one basis, which is costly and time-consuming. Attempts to circumvent this problem are illustrated by Tobin's Beginning Braille (Tobin 1988, revised), a 'programmed instruction' system using tape-recordings and braille booklets. These self-instruction...

Worsening Diarrhea in a 5Year Old Girl

Inconsistent with celiac disease, the duodenum was found by endoscopy to have normally formed villi, but it had an unusual white frosting appearance. On histologic examination, numerous Oil Red stain-positive vacuoles were observed in the villi consistent with the intracellular fat accumulation that occurs in abetalipoproteinemia. Because of the suspected diagnosis, the patient was referred to an ophthalmologist, who also observed pigmentary degeneration of the retina. The patient was started on a low-fat diet, which considerably improved her diarrhea. High-dose oral supplementation of vitamins A and E was also started. She was recommended to return for periodic monitoring of her eyes, to be followed by coagulation and liver function tests.

Higher Visual Processing

A similar distinction needs to be drawn between the visual IQ assessed by tests such as the British Ability Scales and the type of visual deficits described in this chapter. It should not be assumed that children with lower visual IQs are particularly likely to have the visual anomalies described in this chapter. There is no good evidence to suggest that psychometric results obtained in a psychological evaluation can be used to decide which dyslexic children need to see an eye care practitioner.

Neurological And Neuromuscular Disorders

Many hereditary neurological disorders are clinically complex because the nervous system is intimately intertwined with other organ systems. Table 4.14 outlines a broad approach to taking a medical-family history for a neurological condition. This section is followed by more specific guidelines for directed medical-family histories for seizures (Table 4.15), dementia (Table 4.17), and mental illness (Table 4.18). Several hereditary conditions with neurological impairment also include hearing loss (see Section 4.3) and or visual impairment (see Section 4.4). Cardiomyopathies are common in the muscular dystrophies (see Section 4.11). Inherited metabolic disorders are a frequent inherited cause of progressive neurological conditions, particularly in children. Table 4.11 reviews some of the medical-family history indicators of an inborn error of metabolism. Visual impairment Note age at onset (Visual disturbances are frequently associated with neurological disorders, particularly...

Triplet Repeat Disorders and the Inheritance of Dynamic Mutations

Phy may have severe hypotonia and failure to thrive, yet the affected grandparent has only early balding and pre-senile cataracts. Anticipation has mostly been described in autosomal dominant neurological disorders, such as Huntington disease, the spinocerebellar ataxias, and myotonic dystrophy (La Spada et al., 1994). In these conditions, nucleotide runs of three are excessively repeated in the DNA. Thus, they are called trinucleotide or triplet repeat disorders. Spinobulbar muscular atrophy and fragile X syndrome are X-linked neurological trinucleotide repeat disorders.

Internships For Sale How To Secure A Pgy1 Position

Many of the specialized fields of medicine, such as ophthalmology and anesthesiology, begin residency training at PGY-2. According to NRMP classification, these are the advanced specialties. They require entering residents first to complete 1 year of broad clinical training, which is similar in scope to the old freestanding rotating internship required of all fresh graduates before its demise in 1970. Medical students who select a specialty with advanced positions have some extra work on their hands. Fortunately, the same application and matching system can be used to secure an internship position. cal specialty (urology, neurosurgery, and otolaryngology). This position serves as their general surgery internship. The remaining positions are sometimes chosen by students who believe that a pseudosurgical internship would best prepare them for residency, such as those in ophthalmology, emergency medicine, and anesthesiology. Realistically, most preliminary surgery positions are...

Recent Weight Loss and Polyuria in a 52Year Old

Physical examination revealed a blood pressure of 122 72 mm Hg, a regular pulse rate of 64 bpm, and a respiratory rate of 12 minute. Heart sounds were normal with no murmurs, and the lungs were clear to auscultation. Examination of the abdomen revealed no masses or hepatomegaly, and bowel sounds were normal. Ophthalmologic examination showed normal fundi. There was no pedal edema, dorsalis pedis pulses were normal bilaterally, and toes and feet were sensitive to light touch and position. Despite only a relatively mild increase in fasting glucose concentration, the physician was concerned by the increased HbA1c. Although the patient showed no obvious signs of diabetic microvascular complications, the earlier infection raised the possibility of peripheral vascular insufficiency and the resulting susceptibility to infection associated with diabetes.3 The patient was again counseled firmly to resume his exercise and control his diet, and the physician increased the metformin to 1000 mg...

Lymphocytic choriomeningitis virus LCMV A

Mice and hamsters are the primary sources of LCMv infections. Humans acquire this virus by direct contact with infected rodents or by inhaling the virus. So far, more than 49 infants around the world have been diagnosed with congenital LCMv. However, experts really are not sure how many infants have been affected by LCMv before birth because doctors do not routinely look at LCMv as a possible cause of congenital blindness or retardation. In one instance, twin girls from Cochise County, Arizona, were born to a mother who had unknowingly contracted LCMv during pregnancy. One girl was born with vision problems and the other has seizures and severe developmental delays. More than 90 percent of the babies who have contracted the LCMv virus before birth have had adverse effects, the most common of which were vision problems. Other problems include neurological conditions such as and decreased visual acuity.

The Problem With Diagnosing An Inducible Phenotype

Telling just who is or isn't affected with a particular problem is a common problem in many genetic studies, but especially so with situations such as lactose intolerance that have an environmental component. A genetic disease called favism is only detected in individuals with the defect who eat fava beans. Normally, detection of malignant hyperthermia happens because someone undergoes general anaesthetic for surgery. Individuals susceptible to steroid glaucoma will only develop this potentially blinding eye disease if they are exposed to certain corticosteroid medications. So for many of these complex traits with both genetic and environmental elements, many of us have no idea what our phenotype or genotype might be because we have not encountered the conditions that would elicit the trait in someone with the predisposing genotype.

On the termination of the optic tract fibers in the lateral geniculate nucleus

Vision, like all sensory inputs, except for olfaction, is relayed to the cerebral cortex by way of the thalamus. The thalamic relay for vision is the LGN. The LGN in humans and Old World monkeys has an obvious striped appearance, with six layers of neurons separated by interleaved fiber layers. Although, by the end of the nineteenth century, it was clear that the eye projects to the LGN, the pattern of termination of optic tract fibers was not well understood. The true picture was revealed by study of transneuronal atrophy and degeneration. Cells in the LGN that are deprived of their input from the eye shrink or die. Mieczyslaw Minkowski (1920), working in Zurich, studied the LGN of a monkey that had had one eye removed 8 months earlier and that of a 75-year-old woman who had had amblyopia due to a unilateral cataract for 38 years before she died. Minkowski saw that cells in the LGN layers opposite the blind eye, layers 1, 4, and 6, were atrophied. In the ipsilateral LGN, layers 2, 3,...

Trials examining glycemic targets

In the ADVANCE trial (Action in Diabetes and Vascular Disease Preterax and Diamicron MR Controlled Evaluation), 11,140 patients who have type 2 diabetes mellitus were recruited in 200 centers in Australia, Asia, Europe, and North America. The eligibility criteria are broad diagnosis of type 2 diabetes mellitus after 30 years of age, age 55 or more years, and high risk for CVD. Patients are randomized in a 2 x 2 factorial design to an open-label, modified-release (MR) sulfonylurea (gliclazide MR)-based intensive treatment with a goal of achieving a HbA1c level of 6.5 or less versus standard care for glycemia as well as a blood pressure intervention (see later discussion). There are two primary endpoints (1) the composite of stroke, MI, and CV death, and (2) the composite of new or worsening nephrop-athy or microvascular eye disease. The scheduled postrandomization follow-up is 4.5 years. The study is designed to provide 90 power to detect

Biofilms in medical systems

These surfaces include those in water systems that may harbor potentially pathogenic bacteria such as Legionella sp. and that consequently may be protected from chlorination. Biofilms have also been found on contact lenses and contact lens storage cases, for which bacteria induce severe eye irritation and inflammation and may play a role in persistence of the organisms.

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