Sight Gone, But Not Necessarily Lost?

Like all tissues in the body, the eye needs a healthy blood supply to function properly. Poorly developed blood vessels can lead to visual impairment or even blindness. While many of the molecules involved in guiding the development of the intricate blood vessel architecture are known, only now are we learning how these molecules work and how they might affect sight. Reporting in the Oct. 16 issue of Cell, researchers at the Johns Hopkins School of Medicine find that when some cells in the mouse retina are not properly fed by blood vessels, they can remain alive for many months and can later recover some or all of their normal function, suggesting that similar conditions in people may also be reversible.

“This finding is intriguing,” says Jeremy Nathans, M.D., Ph.D., a professor of molecular biology and genetics, neuroscience and ophthalmology at Johns Hopkins and a Howard Hughes Medical Institute investigator. “It suggests that neurons in the retina can survive for an extended period of time even though they have been functionally silenced.”

Three genes named Fz4, Ndp and Lrp5 previously were suspected to be involved in blood vessel development in the human retina. Defects in any of these genes cause hypovascularization a lack of sufficient blood vessels in the retina. Similarly, eliminating any of these genes in mice can lead to hypovascularized retinas.

Mice lacking functional Fz4 have poor blood vessel growth in the retina and are blind, but it was not known whether the blood vessel deficiency was the cause of blindness or whether the absence of Fz4 leads to some other defect that causes blindness. The team found that Fz4 function is required only in blood vessels, where it senses a signal produced by the Ndp gene in other retinal cells.

When the team measured electrical responses in retinal cells of mice lacking Fz4, they found a defect in electrical signaling in the middle layer of the retina the same region lacking blood vessels. The researchers then bathed the Fz4 mutant retinas in oxygen and nutrients to mimic a normal blood supply, and measured electrical signaling in response to light. They found that when provided with oxygen and nutrients, the retinas were able to sense light and generate signals similar to those generated by normal retinas. The team suggests that in the absence of Fz4 the defective blood vessels provide the retinas with only enough oxygen and nutrients to keep the retinal cells alive, but not enough for them to function normally to send electrical signals.

“If the human retina responds to a decrease in blood supply in the same way that the mouse retina responds, then these results may have relevance for those patients with vision loss due to vascular defects,” says Nathans. “In particular, these experiments suggest that if a region of the retina has been deprived of its normal blood supply, then completely or partially restoring that supply may also restore some visual function, even if this happens weeks or months later.”

This study was funded by the National Eye Institute and the Howard Hughes Medical Institute.

Authors on the paper are Yin Ye, Yanshu Wang, Hugh Cahill, Tudor Badea, Philip Smallwood and Nathans of Johns Hopkins, and Minzhong Yu and Neal Peachey of the Cole Eye Institute, Cleveland Clinic Foundation.

Source: Johns Hopkins Medicine

Sun-Sensitizing Medications, Sun Exposure Associated With Common Type Of Cataract

The use of medications that increase sensitivity to the sun, combined with exposure to sunlight, appears to be associated with the risk of age-related cataract, according to a report posted online that will appear in the August print issue of Archives of Ophthalmology, one of the JAMA/Archives journals.

Besides age, several risk factors have been identified for common types of cataract, including smoking, diabetes and hypertension, according to background information in the article. Sunlight and exposure to ultraviolet-B (UV-B) rays have been shown to be associated with cortical cataract, clouding or opacity occurring first on the outer edges of the lenses. Some medications taken by mouth or by injection have been shown to increase sensitivity to the sun, causing signs and symptoms such as itching or rash on areas of the skin exposed to sunlight.

To determine if these medications also affect the association of sun exposure to cortical cataract, Barbara E. K. Klein, M.D., M.P.H., and colleagues at the University of Wisconsin, Madison, studied 4,926 individuals living in Beaver Dam, Wisconsin and first examined between 1988 and 1990. Participants were interviewed about their residential history, which was used to construct a measure of their average annual exposure to ambient UV-B rays. Interviewers also asked participants to bring their medications, and any sun-sensitizing drug-including diuretics, antidepressants, antibiotics and the pain reliever naproxen sodium.

An increasing percentage of study participants reported having taken these types of medications over a 15-year follow-up period (24.1 percent at the beginning of the study, compared with 44.8 percent at the 15-year follow-up). The overall incidence of cataract was not associated with their use or with exposure to sunlight. However, after adjusting for age and sex, an interaction between sun-sensitizing medication use and UV-B exposure was associated with the development of cortical cataract.

“The medications (active ingredients) represent a broad range of chemical compounds, and the specific mechanism for the interaction is unclear,” the authors write. The lens of the eye develops from the same layer of tissue as the skin, and medication that increases the skin’s response to the sun may modify the effect of sunlight exposure on the eye as well.

“Our results need to be evaluated in other populations, especially in view of the increasing frequency of sun-sensitizing medications,” the authors conclude. “If our findings are confirmed, it would be important to examine whether the effect is greater in those with higher levels of ambient sunlight (UV-B) exposure and if dose or duration of medication use is also important. Because cortical cataract is a common lens opacity in adults, present in about 16 percent of the Beaver Dam Eye Study population at the baseline examination, our study findings may be relevant to public health.”

Archives of Opthalmology . 2010;128[8]:(doi:10.1001/archophthalmol.2010.138.)

Archives of Opthalmology

Glaucoma: Silently Stealing Sight From Millions

As you read this sentence, you could be going blind and not know it. Silently, without symptoms, Glaucoma could be stealing your sight, and there is no cure.

January is Glaucoma Awareness Month, and the American Academy of Ophthalmology and its partner the American Glaucoma Society strongly urges everyone to get a complete eye exam, especially if you are in a high risk category, including:

— African-Americans older than 40

— Hispanics

— People with a family history of glaucoma

— Anybody older than 60

— People with adverse health conditions, such as diabetes

— Those who have experienced a serious eye injury

— Those who are severely nearsighted

The National Institutes of Health estimates that 4.2 million Americans have glaucoma, but only half know it.

The second leading cause of blindness in the world, glaucoma accounts for 12 percent of blindness in the United States. And with a rapidly aging Baby Boom generation, these numbers are expected to double in the next decade.

The best defense against glaucoma is detecting it early, said Andrew Iwach, MD, Academy spokesperson.

“Knowing you have glaucoma is one of the most important factors in treating the disease and preventing vision loss,” he said. “So many people are losing their sight and simply do not realize it. Glaucoma is a treatable disease. Vision loss can be minimized. Those who are potentially at risk must take the first step and get an eye exam.”

What is Glaucoma?

Glaucoma is a group of eye diseases that gradually damage the optic nerve, the main conduit carrying visual information from the eye to the brain. Like a video camera with a weak cable link to a television, the picture is compromised.

“Elevated pressure inside the eye damages the optic nerve,” Dr. Iwach said. “Even people with ‘normal’ levels of pressure can experience vision loss from glaucoma. It may begin with the loss of peripheral vision and then advance to a narrow area known as ‘tunnel vision.’ If left untreated, it can lead to total blindness. Sadly, most people don’t notice symptoms until they have already lost significant vision and, unfortunately, this loss is irreversible.”

Dr. Iwach said that although glaucoma can be controlled, vision lost can never be regained. However, medication or surgery can slow or prevent further vision loss. “Glaucoma is a chronic condition that must be monitored for life,” he said. “Early detection is vital to stopping the progress of the disease.”

EyeCare America’s Glaucoma EyeCare Program

EyeCare America, a public service foundation of the American Academy of Ophthalmology, encourages those without insurance to take advantage of its national Glaucoma EyeCare Program.

The program offers glaucoma eye exams for those at increased risk of glaucoma. To see if you, a loved one or a friend, is eligible to receive a referral for an eye exam and care, call 1-800-391-EYES (3937), 24 hours a day, 365 days a year. Eligible callers receive a referral to one of EyeCare America’s 7,300 volunteer ophthalmologists.

Those eligible for a referral through the glaucoma program receive a glaucoma eye exam and the initiation of treatment, if deemed necessary. Uninsured patients will receive the above care at no charge. More information on EyeCare America can be found at: eyecareamerica.

About the American Academy of Ophthalmology

AAO is the world’s largest association of eye physicians and surgeons Eye M.D.s with more than 27,000 members worldwide. Eye health care is provided by the three “O’s” opticians, optometrists and ophthalmologists. It is the ophthalmologist, or Eye M.D., who can treat it all: eye diseases and injuries, and perform eye surgery. To find an Eye M.D. in your area, visit the Academy’s Web site at aao/.

American Academy of Ophthalmology (AAO)
655 Beach St. P.O. Box 7424
San Francisco, CA 94120-7424
United States

Virtual Robots Duped By Illusions Help To Explain Human Vision

A study by researchers at UCL (University College London) explains why
humans see illusions by showing that virtual robots trained to ‘see’
correctly also – as a consequence – make the same visual mistakes that we
do. The study, published in the latest edition of PLoS Computational
Biology, shows that illusions are an inevitable consequence of evolving
useful behaviour in a complex world.

Illusions are defined in the Oxford English Dictionary as “something that
deceives or deludes by producing a false impression.” Visual illusions,
such as the ‘Hermann Grid Illusion’, trick the viewer into
misinterpreting – in this case – shades of grey. The study’s senior
author, Dr.
Beau Lotto, UCL Institute of Ophthalmology, said: “Sometimes the best way
to understand how the visual brain works is to understand why sometimes it
does not. Thus lightness illusions have been the focus of scientists,
philosophers and artists interested in how the mind works for centuries.
And yet
why we see them is still unclear.”

To address the question of why humans see illusions, researchers at the
UCL Institute of Ophthalmology used artificial neural networks,
virtual toy robots with miniature virtual brains, to model, not human
vision as such, but human visual ecology. Dr David Corney in Dr. Lotto’s
trained the virtual robots to predict the reflectance (shades of grey) of
surfaces in different 3D scenes not unlike those found in nature. Although
the robots could interpret most of the scenes effectively, and
differentiate between surfaces correctly, they also – as a consequence –
the same lightness illusions that humans see.

Dr. Lotto said: “In short, they not only get it right like we do, but they
also get it wrong like we do too. This provides causal evidence that
illusions represent not the world as it is, but what proved useful to see
in one’s past interactions with the sources of retinal images. The virtual
robots in this study were driven solely by the statistics of their
training history and used these statistics as the basis of their correct
subsequent incorrect decisions. Similarly, we believe the human brain
generates perceptions of the world in the same way, by encoding the
relationships between images and scenes in our past visual experience and
uses this as the basis for behaving usefully and consistently towards the
sources of visual images.”

Although the artificial neural networks used in the research are much less
complex than the human visual system, this simplicity helped the
researchers to identify and further understand what they believe is a
fundamental principle behind why we see illusion: the statistics of our
visual experiences. As the brain does not have direct contact with the
world, but only an image of the world on the retina which is ambiguous, it
to call on the statistics of how it behaved in the past to understand how
to behave in the future. Dr Corney said: “Every scene is ambiguous, to us,
to animals and to robots. Our eyes and brains have evolved to let us
behave effectively and so survive. So when presented with any image of the
what we see is what would have been useful to see in the past. Illusions
are uncommon and so misinterpreting an image rarely matters.”

Dr. Lotto added: “The study also suggests the first biologically-based
definition of what an illusion is: the condition in which the actual
of a stimulus differs from its most likely source. When we see an illusion
we are seeing the most likely source of the image given history. Since
resolving ambiguous sensory information is a challenge faced by all visual
systems, including the virtual robots in this study, it is likely that
illusions must be experienced by all visual animals regardless of their
particular neural machinery. Visual illusions have been central to the
and philosophy of human consciousness for centuries and this research
demonstrates that how we respond to them can give vital information about
processes behind vision.”

For more information about Professor Lotto’s work, please go to:

Examples of brightness/lightness illusions can be found

CITATION: Corney D, Lotto RB (2007) What Are Lightness Illusions and Why
Do We See Them? PLoS Comput Biol 3(9): e180

Please click here


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Research Highlights Of The September 2009 Issue Of Ophthalmology

Highlights of September’s Ophthalmology, the journal of the American Academy of Ophthalmology (Academy), include a 2009 review by the Academy of the safety and efficacy of a widely used corneal transplant procedure and a warning about an unusual but serious reaction to systemic fluroquinolones, a class of antibiotics used to treat a variety of bacterial infections.

DSEK Deemed Safe, Effective Treatment for Corneal Diseases

Descemet’s Stripping Endothelial Keratoplasty (DSEK) corneal transplant procedure is a safe and effective treatment for corneal endothelial diseases, says a 2009 review by the cornea panel of the Academy’s Ophthalmic Technology Assessment Committee, led by W. Barry Lee, M.D. The panel reached this conclusion through a comprehensive review of pertinent studies published from 1980 to 2009. Eighty-five percent of corneal transplants performed in the United States are associated with endothelial diseases. The cornea is the eye’s clear outer tissue that refracts, or bends, incoming light to focus images on the retina at the back of the eye; the endothelial layer lines the back surface of the cornea and regulates water levels (hydration). In February 2009 the Board of Trustees approved the corneal panel’s conclusions for use in official Academy statements.

In outcome comparisons derived from the review, DSEK was superior to penetrating keratoplasty (PK) – the dominant procedure prior to DSEK’s development – in terms of earlier recovery and stability of vision, refractive status after surgery, and specific risks and complications associated with surgery and recovery. The most common DSEK complications apparently do not hinder ultimate recovery of vision in most patients. DSEK and PK outcomes were similar in terms of survival of the transplanted cornea, visual sharpness (acuity) and endothelial cell loss, and specific surgical risks and complication rates.

“To further improve DSEK and related procedures and provide the best patient care, we need prospective clinical studies to set expectations for long-term endothelial cell survival and to determine acceptable complication rates,” Dr. Lee said. “Another important research area is how to improve tissue (donor cornea) preparation and surgical techniques to increase endothelial cell survival,” he added.

Seeing Double? A Type of Antibiotic May be the Cause

A 2009 study finds that a class of antibiotics known as fluoroquinolones, administered systemically to treat a broad range of bacterial infections, may cause double vision (diplopia) in some patients. Researchers at the Casey Eye Institute, Oregon Health Sciences University (OHSU), launched the first investigation of this problem after the National Registry of Drug-Induced Ocular Side Effects at OHSU received multiple reports of diplopia associated with systemic fluoroquinolones. This antibiotic type has side effects not seen with other antibiotics, including tendon dysfunction, and it is possible that tendinitis in the muscles around the eyes could cause double vision. Fluoroquinolones treat infections including bacterial or chronic bronchitis, pneumonia, sinusitis, and some skin infections.

The researchers, led by Frederick W. Fraunfelder, M.D., found 171 cases between 1986 and 2009 of fluoroquinolone use associated with double vision through a review of reports from the Food and Drug Administration, World Health Organization, and the National Registry of Drug-Induced Ocular Side Effects. The median patient age was 51.6 years, medication doses were within recommended levels, and the interval from starting medication to onset of double vision was 9.6 days on average. Medication was discontinued in 53 patients, and diplopia resolved in all cases.

“Doctors need to be aware of this potential reaction when prescribing these antibiotics and consider stopping therapy if diplopia occurs,” Dr. Fraunfelder said. He also said that special care should be taken with patients who are older than 60, have had renal failure, or are taking steroids, and that thorough ophthalmic and neurological exams should be done to rule out other causes of double vision.

Mary Wade

American Academy of Ophthalmology

University Of Southern California Ophthalmologist And Biomedical Engineer Mark Humayun Elected To Institute Of Medicine

University of Southern California (USC) ophthalmologist and biomedical engineer Mark Humayun has been elected to the prestigious Institute of Medicine (IOM) for his groundbreaking work to restore sight to the blind. The IOM made the announcement on Oct. 12 at its 39th annual meeting.

Election to the IOM is considered one of the highest honors in the fields of health and medicine and recognizes individuals who have demonstrated outstanding professional achievement and commitment to service.

Humayun, M.D., Ph.D., is professor of ophthalmology, cell and neurobiology, and biomedical engineering at the Keck School of Medicine of USC, the Doheny Eye Institute at USC and the USC Viterbi School of Engineering. His research projects focus on the treatment of the most debilitating and challenging eye diseases through advanced engineering. He is also the director of the Department of Energy Artificial Retina Project and co-inventor of the retinal prosthesis-an implantable artificial retina that has restored partial sight to blind patients.

“I am extremely honored to be elected into the Institute of Medicine,” Humayun said. “I would like to thank my colleagues and my family for their support, and I am looking forward to contributing as a member to the Institute of Medicine”

Humayun has been voted one of the Best Doctors in America and has received numerous research awards, including being named Innovator of the Year by R&D Magazine in 2005.

“The election of Mark Humayun to the Institute of Medicine is a great honor that recognizes his status as an outstanding leader in bioscience,” said Keck School of Medicine Dean Carmen A. Puliafito, M.D., M.B.A. “Dr. Humayun’s dedication to medicine and science, and his commitment to collaboration across disciplines, has profoundly improved the quality of life for many patients.”

Dana Goldman, Ph.D., professor and the Norman Topping Chair in Medicine and Public Policy at the USC School of Policy, Planning and Development was also elected to the IOM. Goldman oversees the newly created Leonard D. Schaeffer Center for Health Policy and Economics at USC and also has a faculty appointment at the School of Pharmacy.

New IOM members are elected by current active members through a highly selective process that recognizes individuals who have made major contributions to the advancement of the medical sciences, healthcare, and public health. IOM’s total membership is 1,778.

The Institute of Medicine is unique in its structure as both an honorific membership organization and an advisory organization. Established in 1970 by the National Academy of Sciences, IOM has become recognized as a national resource for independent, scientifically informed analysis and recommendations on health issues. With their election, members make a commitment to volunteer their service on IOM committees, boards, and other activities. Studies and initiatives during the past year include: a review of the long-term effects of traumatic brain injury among military personnel; an assessment of health effects due to lack of insurance; recommendations for comparative effectiveness research priorities; new guidelines for how much weight women should gain during pregnancy; a blueprint for American leadership in advancing global health; a strategy for preventing medical conflicts of interest; and a series of meetings on improving healthcare value through evidence-based medicine.

University of Southern California

Vision And Mobility For People With Tunnel Vision May Be Improved By New Device

Scientists at Schepens Eye Research Institute, an affiliate of Harvard Medical School, say a visual aid they invented promises to improve the visual abilities of people with tunnel vision. In the first study to evaluate this small high tech device, the research team saw a significant increase in the effectiveness and speed with which visually impaired individuals found objects. The study — in the September issue of the Journal of Investigative Ophthalmology & Visual Science — shows that this device, which combines a tiny camera, pocket-sized computer and transparent computer display on a pair of glasses, may offer the most effective assistance to date for this patient population.

“We are very pleased with the results of this first evaluation and hope that with further study and refinement, we may soon make this device available for the public,” says low vision expert Dr. Eli Peli, the inventor, a senior scientist at Schepens, and a professor of ophthalmology at Harvard Medical School and the senior author of the study,

About one in 200 Americans over age 55 suffers from tunnel vision, as a result of diseases such as retinitis pigmentosa (RP) and glaucoma. RP can begin to affect vision in one’s teen years and may become quite severe tunnel vision by middle age. Residual tunnel vision occurs when peripheral or side vision is destroyed, leaving only a small window of central vision. The field of view of these patients can be likened to looking through the tube of a roll of paper towels. Thus, tunnel vision can often cause the individual to bump into or trip over obstacles. “Navigating city streets or buildings can be quite challenging,” says Dr. Gang Luo, the study’s first author, adding that for a person with tunnel vision, finding a misplaced item is like searching for a key in a dark room using a tiny flashlight. Luo is a research associate at Schepens Eye Research Institute and an instructor in Ophthalmology at Harvard Medical School. .

Until now, patients primarily have relied on long canes to warn them of obstacles just in front of them. Glasses that act as reverse binoculars, miniaturizing and pulling in the missing parts of their visual field, were suggested and tried in the past. “The minifying glasses make things so small that detailed visual information is sacrificed, so most patients have given up these spectacles, and the most used type was discontinued last year” says Peli.

Peli’s new visual aid – which he developed with the help of MicroOptical Corp. of Westwood, MA – allows the patients to see detailed visual information through the transparent display, while also viewing a superimposed minified outline version of a wider visual field. The tiny computer-video system provides updated outline information 30 times per second. When a patient becomes aware of a possible obstacle or important object in the superimposed outline image, he can move his head and eyes to look directly at the object through the display.

The purpose of the current study was to evaluate how effective the device would be in helping people with tunnel vision when searching for objects. Twelve patients with tunnel vision were asked to find targets that were projected outside their residual visual fields. The researchers found that the search directness was greatly improved for all patients when the device was used. They also found a significant reduction in search time (22%) in patients with a visual field wider than 10??.

Peli and his team believe that the performances of patients could be improved further – with additional training – even for those with smaller visual fields. “All patients only had an hour of training on this device before they were tested,” says Luo “The search directness was improved for all subjects, which means they were not searching aimlessly, as they did without the device. However, the speed of head and eye movements was reduced when patients used the yet unfamiliar device. We believe that a few days of training would improve their speed and thus increase their search abilities dramatically.”

Based on these results, and following further improvement of the device, the team will test the usefulness of the device by providing it to patients for use in their homes and for outdoor activities.

To view an illustration of the contoured computer display, go to To obtain a copy of the study go to the IOVS website at iovs/.

Schepens Eye Research Institute is an affiliate of Harvard Medical School and the largest independent eye research institute in the world.

Contact: Patti Jacobs

Schepens Eye Research Institute

Raising Awareness And Improving Eye Health Of 75 Million Aging Boomers

“Am Eye Healthy?” is the question more
than 75 million aging Baby Boomers should ask themselves, according to a new
health education campaign launched today in Washington, DC. The new effort
aims to help Americans understand the importance of regular eye exams and
vision screenings and the value of early detection, treatment and
rehabilitation options. Members of Congress including Senator Hillary Rodham
Clinton and Representative Gene Green helped launch the bi-partisan supported
campaign at an event on Capitol Hill.

“In eye health, an ounce of prevention truly is worth a pound of cure.
There are more treatment and rehabilitation options now than ever, but early
detection is critical. This campaign will help more Americans learn about the
importance of making regular eye screenings and exams a key part of their
preventative health care,” said Senator Clinton.

At today’s launch and throughout the year, the campaign will offer free
vision screenings, educational materials and a user-friendly Web site,
ameyehealthy. Campaign partner Prevent Blindness America and
its affiliates are hosting local vision screenings today along with other “Am
Eye Healthy?” partners in Florida, Georgia, Illinois, New York, Ohio,
Tennessee, Texas and Washington, DC.

“We want people to think about their eye health as part of their general
well-being,” said Daniel D. Garrett, senior vice president of Prevent
Blindness America. “We are pleased to be offering screenings in conjunction
with our local chapters and other campaign partners in eight states.”

A collaboration of over 20 consumer, senior, patient and health groups,
working in partnership with Novartis Ophthalmics, “Am Eye Healthy?” has the
power of health advocacy and educational partners on the national and local
levels. Partners include the AMD Alliance International, American Association
of People with Disabilities, American Council of the Blind, American
Foundation for the Blind, American Society on Aging, Congressional Black
Caucus Foundation, Consumer Action, Foundation Fighting Blindness, League of
United Latin American Citizens, Lighthouse International, National Alliance
for Caregiving, National Association for Visually Handicapped, National Caucus
and Center On Black Aged, National Consumers League, National Hispanic Council
on Aging, Older Women’s League, Prevent Blindness America, The Seniors
Coalition, SeniorNet, and 60 Plus Association.

“Early detection through annual eye exams can prevent or slow vision loss.
Eye exams can uncover problems in the eye before symptoms appear or vision
loss occurs,” said Dr. Lorraine Marchi, founder and CEO of the National
Association for Visually Handicapped. “Common diseases associated with aging,
including high blood pressure and diabetes, can lead to eye problems, as can
eye tumors, retinal disorders and glaucoma, which may have no symptoms in the
early stages. These conditions don’t have to mean vision loss, though.

Medical research has made great strides. With early detection, there are more
ways than ever before to help protect vision.”

For more information about the campaign or eye health, visit
ameyehealthy or see an eye care professional.

About Prevent Blindness America

Founded in 1908, Prevent Blindness America is the nation’s leading
volunteer eye health and safety organization dedicated to fighting blindness
and saving sight. Focused on promoting a continuum of vision care, Prevent
Blindness America touches the lives of millions of people each year through
public and professional education, advocacy, community and patient service
programs and research. These services are made possible through the generous
support of the American public. Together with a network of affiliates,
divisions and chapters, it’s committed to eliminating preventable blindness in

Prevent Blindness America

Children With Lazy Eye Need Only Wear Patches A Few Hours A Day

A child with amblyopia (lazy eye) does not have to wear a patch all day; three to four hours daily for a total of twelve weeks is all that is usually needed to improve vision, according to an article published in the British Medical Journal (BMJ). The writers say that wearing a patch all day long for several years is too much.

Amblyopia happens when the vision pathways between the eye and the brain are disturbed. The patient commonly experiences blurred vision and/or has strabismus (crossed eyes).

Previous studies have demonstrated that wearing a patch (occlusion therapy) can help improve vision. Results have shown that making the child wear the patch all day (maximal doses) offers the child no more improvement than six hours a day (substantial doses). Surprisingly, many doctors still make their patients wear the patch for too many unnecessary hours.

Scientists from City University, London, England, and McGill University, Montreal, Canada, decided to find out how much occlusion treatment a child with amblyopia needs to get the best results. The study was funded by Fight for Sight.

In this study, all the 97 children, aged 3-8 years had amblyopia. All of them underwent a full ophthalmic assessment and were told to wear glasses during their waking hours for a period of 18 weeks. At the end of this period the number of children who still had amblyopia went down to 80. These children were split into two groups; one group wore a patch for six hours a day while the other group did so for twelve hours a day – for a total of 12 weeks.

The patches had two electrodes fitted inside them to register the exact amount of occlusion time each child was receiving. The visual function of each participant was recorded every two weeks.

At the end of the period the researchers could not detect any difference in visual activity between the two groups. They also found that the real amount of time the children were receiving occlusion therapy was much lower than what had been prescribed. The 12 hour per day group’s average daily occlusion time was 6.2 hours, while the 6 hour per day group’s was 4.2 hours.

Children over 4 years of age who received less than three hours treatment per day had significantly worse outcomes than those who received from 3-6 hours per day. However, the children who received 3-6 hours per day treatment enjoyed virtually similar improvements as the children who had 6-12 hours per day.

It was also noticed that the younger the patient was the less total occlusion hours he/she required. In fact, the 4 year-olds required less than three hours per day.

The writers explain that it should be a clinical priority to start the initial real occlusion rate of 3-4 hours per day. As eye patching can be very upsetting for both the patient and his/her family, doctors should endeavor to keep the amount of time necessary for best outcomes down to a minimum.

“Objectively monitored patching regimens for treatment of amblyopia: randomised trial”
Catherine E Stewart, David A Stephens, Alistair R Fielder, Merrick J Moseley
BMJ doi:10.1136/bmj.39301.460150.55

Dr. Peli Honored For Innovations That Improve Vision For Visually Impaired

Dr. Eli Peli, a senior scientist at Schepens Eye Research Institute, has been selected by the Society for Information Display for the Otto Schade Prize. Peli will receive the award at a special presentation at the Society’s Awards Banquet on May 24, 2010 in Seattle.

Peli was chosen “for his many outstanding contributions to vision science and its application to image quality evaluation and enhancement, including pioneering efforts in improving display performance for populations with special visual needs,” according to the prize citation.

According to Dr. Chris King, SID Honors and Awards Chair, “Professor Eli Peli was chosen for his work, which has used vision science to improve both the image quality of electronic displays and the visual performance of those with special visual needs.”

The Moakley Scholar in Aging Eye Research and co-director of Research at Schepens Eye Research Institute, Peli is also a professor of Ophthalmology at Harvard Medical School and serves on the faculties of the New England College of Optometry, Tufts University School of Medicine, the University of York in the UK, and Dalian Maritime University in China.

A dedicated clinician, since 1983 he has been caring for visually impaired patients as the director of the Vision Rehabilitation Service at Tufts-Medical Center in Boston. His research at Schepens Eye Research Institute has been focused on creating new and innovative optical and electro-optical devices to help his patients and others with impaired vision caused by diseases such as macular degeneration, glaucoma and retinitis pigmentosa live better despite their visual impairments.

SID is honoring Peli because many of his innovations have used the latest image processing and information display technologies in new ways. For instance, to help patients with tunnel vision, Peli has created a pair of high-tech glasses that display a cartoon-like minified view of missing parts of the patient’s visual field, while also allowing a normal central view of the surroundings. Peli has also pioneered and refined techniques to modify television displays to improve contrast in ways that are particularly useful for those with macular degeneration. In pursuit of these projects Peli has developed and implemented innovative methods for the evaluation of contrast in images and the measurement of perceived image quality, the subject of this prestigious prize.

A Fellow of numerous international scientific societies, including the SID, Peli is also the recipient of many other prestigious awards, such as the 2001 Glenn A. Fry Lecture Award and the 2009 William Feinbloom Award from the American Academy of Optometry, the 2004 Alfred W. Bressler Prize in Vision Science from the Jewish Guild for the Blind, the 2006 Pisart Vision Award from the Lighthouse International, and the 2009 Alcon Research Institute Vision Award.

Patti Jacobs
Schepens Eye Research Institute