November 10, 2009, 8:55 AM CT

The world's most common operation

As a number of as 10 million people around the world suffer from cataracts. Thomas Kohnen of the Goethe University in Frankfurt and his coauthors discuss cataract surgery with the implantation of an artificial lens in the current issue of Deutsches rzteblatt International (Dtsch Arztebl Int 2009; 106[43]: 695�).

Blindness is commonly due to opacification of the lens. In Gera number of alone, more than 600,000 cataract operations are performed each year. Cataracts can be either congenital or acquired; age-related opacification of the lens is the most common type. The main symptom of cataract is slowly progressive worsening of vision, but glare disability and nearsightedness can also be signs of the disease.

Cataract operations are now commonly performed on an outpatient basis. The eye is anesthetized, pretreated with antibiotics, and surgically opened. New approaches permit the operation to be performed through an incision smaller than 2 mm. In the phacoemulsification technique, the lens is emulsified and aspirated away through a vibrating hollow needle. The surgeon then implants an intraocular artificial lens. Patients without any other diseases of the eye can achieve a visual acuity of 1.0 or even better. Special optical designs for the artificial lens can further optimize the quality of vision and thereby improve patient satisfaction......... Posted by: Mike      Read more         Source

November 6, 2009, 8:55 AM CT

Research Study On Near Vision

The Cornea and Laser Eye Institute is participating in a research study to determine if an investigational corneal inlay can safely and effectively reduce the need for reading glasses. Dr. Peter Hersh, the study doctor, will perform the procedures.

The investigational AcuFocus Corneal Inlay (ACI) is intended to improve near vision in patients with presbyopia, which is the loss of near vision, and reduce dependency on reading glasses. Qualified participants will receive the procedure at no charge.

Presbyopia, the loss of near vision happens when the eye's natural lens loses the ability to focus light from both far and near objects. As a result, near tasks like reading or computer work are blurry. However, it is possible for far objects to still be clear. Presbyopia is a natural occurrence that happens to most of us by age 45. Patients 45 to 60 years are eligible to participate.

Smaller than a contact lens, the ACI Corneal Inlay looks like a small brown ring. It is 5 microns thick and 3.8 mm across with a small hole in the center. Over 8,000 tiny holes throughout the ACI help maintain the health of the cornea. It is placed within the body of the cornea, directly in front of the pupil. The ACI lets the central rays of light continue on to the retina while blocking out some of the more out-of-focus rays. This is similar to the effect seen when one looks through a small pinhole. This increased focus may improve near vision. With the ACI placed in one eye, the depth of focus is anticipated to provide improved near and in-between vision while having little effect on far away vision......... Posted by: Mike      Read more         Source

June 3, 2009, 5:14 AM CT

How the Brain Processes What the Eye Sees

Scientists at the Center for Molecular and Behavioral Neuroscience (CMBN) at Rutgers University in Newark have identified the need to develop a new framework for understanding "perceptual stability" and how we see the world with their discovery that visual input obtained during eye movements is being processed by the brain but blocked from awareness.

The process of seeing requires the eyes to move so light can hit the photoreceptors at the center of each retina, which then pass that information to the brain. If we were cognizant of the stimulus that passes before the eyes during the two to three times they move every second, however, vision would consist of a series of sensations of rapid motion rather than a stable perception of the world. To achieve perceptual stability, current theory has held that visual information gained during an eye movement is eliminated, as if cut off by a camera's shutter, and removed from processing.

As published in Current Biology (http://www.cell.com/current-biology), significant new research conducted by assistant professor Bart Krekelberg and post-doctoral researcher Tamara L. Watson now shows that theory of saccadic suppression is incorrect and what the brain is doing instead is processing information gained during eye movement but blocking it from being reported......... Posted by: Daniel      Read more         Source

April 7, 2009, 5:26 AM CT

How the retina works: Like a multi-layered jigsaw puzzle

About 1.25 million neurons in the retina -- each of which views the world only through a small jagged window called a receptive field -- collectively form the seamless picture we rely on to navigate our environment. Receptive fields fit together like pieces of a puzzle, preventing "blind spots" and excessive overlap that could blur our perception of the world, as per scientists at the Salk Institute for Biological Studies.

In the April 7 issue of the journal Public Library of Science, Biology, the researchers say their findings suggest that the nervous system operates with higher precision than previously appreciated and that apparent irregularities in individual cells may actually be coordinated and finely tuned to make the most of the world around us.

Previously, the observed irregularities of individual receptive fields suggested that the collective visual coverage might be uneven and irregular, potentially posing a problem for high-resolution vision. "The striking coordination we found when we examined a whole population indicated that neuronal circuits in the retina may sample the visual scene with high precision, perhaps in a manner that approaches the optimum for high-resolution vision," says senior author E.J. Chichilnisky, Ph.D., an associate professor in the Systems Neurobiology Laboratories......... Posted by: Mike      Read more         Source

March 31, 2009, 3:15 PM CT

Vision therapy to combat vision problems

You've probably been there. In a doctor's office, being advised to do what you dread exercise. You get that feeling in your gut, acknowledging that, indeed, you should exercise but probably won't. Now imagine that the doctor is your optometrist.

Don't clean your glasses. You read that right. Eye exercises are used to treat a variety of vision disorders, as per Dr. Janice Wensveen, clinical associate professor at the University of Houston's College of Optometry.

Patient reactions to this quite common prescription range between surprise and relief, she said, but doing the treatment can improve their performance at school and work.

"They're curious, particularly when we tell them, instead of putting a Band-Aid on it like we do with glasses or contact lenses, we're actually going to solve your problem. You're going to be cured, and that's something we don't very often do," she said.

The standard at-home prescription is known as "pencil push-up treatment," said Wensveen, who practices at the University Eye Institute's Vision Therapy Clinic in the Family Practice Service.

"Patients visually follow a small letter on a pencil as they moved the pencil closer to the nose. The goal is to be able to keep the letter clear and single until it touches your nose"......... Posted by: Mike      Read more         Source

March 30, 2009, 5:10 AM CT

Action video games improve vision

To learn whether high-action games could affect contrast sensitivity, Bavelier, in collaboration with graduate student Renjie Li and his colleagues Walt Makous, professor of brain and cognitive sciences at the University of Rochester, and Uri Polat, professor at the Eye Institute at Tel Aviv University, tested the contrast sensitivity function of 22 students, then divided them into two groups: One group played the action video games "Unreal Tournament 2004" and "Call of Duty 2." The second group played "The Sims 2," which is a richly visual game, but does not include the level of visual-motor coordination of the other group's games. The volunteers played 50 hours of their assigned games over the course of 9 weeks. At the end of the training, the students who played the action games showed an average 43% improvement in their ability to discern close shades of grayclose to the difference she had previously observed between game players and non-game playerswhereas the Sims players showed none.

"To the best of our knowledge, this is the first demonstration that contrast sensitivity can be improved by simple training," says Bavelier. "When people play action games, they're changing the brain's pathway responsible for visual processing. These games push the human visual system to the limits and the brain adapts to it, and we've seen the positive effect remains even two years after the training was over"......... Posted by: Mike      Read more         Source

February 26, 2009, 6:07 AM CT

Retinal "Dark Cells" Imagined

A layer of "dark cells" in the retina that is responsible for maintaining the health of the light-sensing cells in our eyes has been imaged in a living retina for the first time.

The ability to see this nearly invisible layer could help doctors identify the onset of a number of diseases of the eye long before a patient notices symptoms. The findings are reported today's issue of Investigative Ophthalmology and Visual Science.

"Our goal is to figure out why macular degeneration, one of the most prevalent eye diseases, actually happens," says David Williams, director of the Center for Visual Science and professor in the Institute of Optics at the University of Rochester. "Macular degeneration affects one in 10 people over the age of 65, and as the average age of the U.S. population continues to increase, it is only going to get more and more common. We know these dark retinal cells are compromised by macular degeneration, and now that we can image them in the living eye, we might be able to detect the disease at a much earlier stage".

In 1997, Williams' team was the first to image individual photoreceptor cells in the living eye, using a technique called adaptive optics, which was borrowed from astronomers trying to get clearer images of stars. To image the dark cells behind the photoreceptors, however, Williams employed adaptive optics with a new method to make the dark cells glow brightly enough to be detected......... Posted by: Mike      Read more         Source

January 30, 2009, 6:01 AM CT

How vision sends its message to the brain

Researchers have known for more than 200 years that vision begins with a series of chemical reactions when light strikes the retina, but the specific chemical processes have largely been a mystery. A team of scientists from the United States and Switzerland, have she new light on this process by "capturing" this chemical communication for future study. This research, reported in the February 2009 issue of The FASEB Journal (http://www.fasebj.org), may lead to the development of new therapys for some forms of blindness and vision disorders.

At the center of the discovery is the signaling of rhodopsin to transducin. Rhodopsin is a pigment in the eye that helps detect light. Transducin is a protein (sometimes called "GPCR") which ultimately signals the brain that light is present. The scientists were able to "freeze frame" the chemical communication between rhodopsin and transducin to study how this takes place and what goes wrong at the molecular level in certain disorders.

As per Krzysztof Palczewski, a senior scientist involved in the research, "The results may have important implications for discovery and development of more specific medicines to treat GPCR-linked dysfunction and disease." Examples of health problems involving GPCR dysfunction include blindness, diabetes, allergies, depression, cardiovascular defects and some forms of cancer......... Posted by: Mike      Read more         Source

January 15, 2009, 7:08 PM CT

Eye injuries caused by paintballs

Paintballs can cause severe and 'visually devastating' eye injuries, particularly when used in unsupervised settings without proper eye protection, reports a study in the recent issue of the American Journal of Ophthalmology (www.AJO.com), published by Elsevier.

"Eye injuries secondary to high-velocity paintballs can cause tremendous damage to vital ocular structures often requiring extensive surgical intervention," comments Dr. Kyle J. Alliman of Bascom Palmer Eye Institute, University of Miami Miller School of Medicine. "Unfortunately, visual loss is often permanent".

Dr. Alliman and his colleagues analyzed the characteristics and outcomes of 36 patients treated for paintball injuries to the eye at Bascom Palmer Eye Institute between 1998 and 2005. The patients were mainly young men, average age 21 years.

The injuries were often quite severe, including rupture of the eyeball in 28 percent of patients and detached retina in 19 percent. Surgery was mandatory in 81 percent of patientsincluding eventual removal of the eye (enucleation) in 22 percent. Even when the eye was saved, a number of patients had permanent visual loss. Overall, near-normal vision (20/40 or better) was restored in only 36 percent of eyes.

All of the patients were injured when using paintballs in a "non-recreational, uncontrolled setting," as per Dr. Alliman. None of the injuries occurred in formal, sponsored event. In all but one of the 36 cases, the patient was not wearing any type of eye protection when the injury occurred......... Posted by: Mike      Read more         Source

January 6, 2009, 7:32 PM CT

When do older drivers stop driving?

With 30 million drivers in the US aged 65 and over, we count on older Americans to recognize when they can no longer drive safely and decide that it's time to stay off the road. A newly released study finds that a decrease in vision function is a key factor in bringing about this decision.

The Salisbury Eye Evaluation and Driving Study (SEEDS), conducted by scientists affiliated with Johns Hopkins University, looked at changes in vision, cognition and the general health status of more than 1,200 licensed drivers aged 67-87 in Salisbury, MD, a community with limited public transportation. SEEDS is unique, in that the scientists performed comprehensive tests of both vision and cognitive function.

The results, recently published in Investigative Ophthalmology & Visual Science, reveal that after a year, 1.5 percent of the drivers had given up driving, and another 3.4 percent had restricted their driving. The most common predictors of stopping or decreasing driving were slow visual scanning, psychomotor speed and poor visuo-constructional skills, as well as reduced contrast sensitivity. (These skills are necessary to help drivers be aware of and respond to other cars, road conditions and road signs. Contrast sensitivity is the ability to detect detail in shades of gray; it is necessary for driving in poor weather and low lighting.)........ Posted by: Mike      Read more         Source

October 7, 2008, 10:50 PM CT

Atomic-resolution views suggest function of enzyme

An atomic-resolution view of an enzyme found only in the eye has given scientists at the University of Washington (UW) clues about how this enzyme, essential to vision, is activated. The enzyme, phosphodiesterase 6 (PDE6), is central to the way light entering the retina is converted into a cascade of signals to the brain.

This particular form of the enzyme comes from the cone photoreceptors of the retina and has not been well-researched, in contrast to its rod form. Rods are involved in night vision and motion sensation; the cones are responsible for color sensitivity, visual acuity, daylight vision, and adjustment to bright light.

The section of the enzyme molecule that most interests the scientists is the so-called GAF A domain. A small messenger molecule, cGMP, binds to the GAF A domain to regulate the enzyme.

"The domain binds to this small molecule with extremely high sensitivity," said UW biochemist Clemens Heikaus, who along with Sergio E. Martinez, now a research associate at Rutgers, carried out the study. "From our structure, we can infer why it prefers cGMP over other messenger molecules." He added that the domain is quick in recognizing and responding to the messenger molecule to create an instantaneous flow of information to the brain......... Posted by: Mike      Read more         Source

September 11, 2008, 9:25 PM CT

Rural HIV care has economic and health implications

An Indiana University study observed that HIV care providers in rural Indiana report significant stigma and discrimination in the rural medical referral system surrounding issues of HIV and substance abuse. Providers felt that these factors impeded their ability to offer quality care to their patients.

"The findings of this study demonstrate inefficiencies in our public health care system and our inability to link people easily to a range of health care providers in rural areas," said Michael Reece, lead investigator of the study and director of The Center for Sexual Health Promotion in Indiana University Bloomington's School of Health, Physical Education and Recreation. "This also has an important economic impact given that our investments in the public health system may not be achieving the outcomes we need, such as improvements in health status."

While most studies involving HIV and stigma rely on patient perspectives, this study focused solely on the perspectives of providers serving rural Indiana residents. Providers reported that some rural physicians refused to provide care for their patients. They also reported widespread stigmatizing comments and behavior from the rural medical community.

The study, "HIV Provider Perspectives: The Impact of Stigma on Substance Abusers Living with HIV in a Rural Area of the United States," appears in the latest issue of the journal AIDS Patient CARE and STDs. For Reece, focusing research locally is important......... Posted by: Mike      Read more         Source

September 11, 2008, 9:21 PM CT

Keeping nerve axons on target

Neurons constituting the optic nerve wire up to the brain in a highly dynamic way. Cell bodies in the developing retina sprout processes, called axons, which extend toward visual centers in the brain, lured by attractive cues and making U-turns when they take the wrong path. How they find targets so accurately is a central question of neuroscience today.

Using the mouse visual system, a team of Salk Institute for Biological Studies researchers led by Dennis O'Leary, Ph.D., identified an unanticipated factor that helps keep retinal axons from going astray. They report in the Sept. 11 issue of Neuron that p75, a protein previously known to regulate whether neurons live or die, leads a double life as an axon guidance protein.

"Historically, we thought that factors that mediate cell survival and those controlling axon guidance were part of two separate processes," says O'Leary, a professor in the Molecular Neurobiology Laboratory, "But in this study we show a direct interaction between these two systems".

Collaborating with Kuo-Fen Lee, Ph.D., professor in the Clayton Foundation Laboratories for Peptide Biology, the O'Leary team observed a defect in mice genetically engineered to lack p75. Through their synaptic connections, retinal axons develop a two-dimensional map of the retina in their targets in the brain. In the mice lacking p75, retinal axons stopped short of their final target and formed a map that was shifted forward to the superior colliculus, a major visual center in the brain......... Posted by: Mike      Read more         Source

September 8, 2008, 7:35 PM CT

Spirituality is important to eye patients

Patients visiting an ophthalmologist report that prayer is important to their well-being and that God plays a positive role in illness, as per a report in the recent issue of Archives of Ophthalmology, one of the JAMA/Archives journals.

"Ethical medical practice includes doctor behavior, beyond technical competence, that promotes healing and optimizes the patient's welfare," the authors write as background information in the article. "The doctor who respects the patient as a person with dignity must acknowledge the patient's value system to establish a relationship that permits conversations that nourish trust for joint therapeutic decision making. For a number of patients, religion and spirituality is important to their value system and may represent a unique source of motivation and coping with life events, including the experience of personal illness (illness refers to the response of a patient to a disease)".

Gina Magyar-Russell, Ph.D., of the Johns Hopkins School of Medicine, Baltimore, and his colleagues distributed a brief questionnaire to 124 patients visiting the office of one ophthalmologist. The 14-question survey was completed by the patient and collected without any identifying information, so patients could be assured the answers would not affect their care......... Posted by: Mike      Read more         Source

July 23, 2008, 4:37 PM CT

Human visual system could make powerful computer

Since the idea of using DNA to create faster, smaller, and more powerful computers originated in 1994, researchers have been scrambling to develop successful ways to use genetic code for computation. Now, new research from a professor at Rensselaer Polytechnic Institute suggests that if we want to carry out artificial computations, all we have to do is literally look around.

Assistant Professor of Cognitive Science Mark Changizi has begun to develop a technique to turn our eyes and visual system into a programmable computer. His findings are published in the latest issue of the journal Perception

Harnessing the computing power of our visual system, as per Changizi, requires visually representing a computer program in such a way that when an individual views the representation, the visual system naturally carries out the computation and generates a perception.

Ideally, we would be able to glance at a complex visual stimulus (the software program), and our visual system (the hardware) would automatically and effortlessly generate a perception, which would inform us of the output of the computation, Changizi said.

Changizi has begun successfully applying his approach by developing visual representations of digital circuits. A large and important class of computations used in calculators, computers, phones, and most of today's electronic products, digital circuits are constructed from assemblies of logic gates, and always have an output value of zero or one......... Posted by: Mike      Read more         Source

July 22, 2008, 8:30 PM CT

How carrots help us see the color orange

One of the easiest ways to identify an object is by its color -- perhaps it is because children's books encourage us to pair certain objects with their respective colors. Why else would so a number of of us automatically assume carrots are orange, grass is green and apples are red?

In two experiments by Holger Mitterer and Jan Peter de Ruiter from the Max Planck Institute for Psycholinguistics, perception of color and color constancy (the ability to see the same color under varying light conditions) were examined using different hues of orange and yellow. By using these hues on different objects, the scientists hoped to show that knowledge of objects can be used to identify color.

In one experiment, half of the participants saw traditionally-colored orange objects in their respective hue, while the other participants saw the same objects in an ambiguous hue between yellow and orange. The participants that saw the ambiguous hue on traditionally-colored orange objects later called the item with that ambiguous hue "orange". Apparently, seeing the ambiguous hue on a traditionally-colored orange objects led participants to redefine that hue to be proper "orange".

In the second experiment, participants saw the same hues, but now on objects that could be any color (e.g., a car). Some participants were shown objects that ranged from the ambiguous color from the first experiment to a strong yellow hue, while others were shown objects in a range of strong orange hues to the ambiguous color. Just as in the first experiment, participants then had to identify a sock that had been colored with an ambiguous hue. This second experiment revealed no differences between the two groups, showing conclusively that it was only the knowledge of how objects are naturally colored that made them redefine the colors in the first experiment......... Posted by: JoAnn      Read more         Source

June 23, 2008, 7:16 PM CT

Retinal hemorrhaging and motor vehicle crashes

The severity of retinal hemorrhaging for young children in motor vehicle crashes is closely corcorrelation to the severity of the crash, as per a new study by scientists at the Medical College of Wisconsin in Milwaukee. Retinal hemorrhages occur when the blood vessels lining the retina rupture, resulting in bleeding onto the surface of the retina.

The study, by Jane Kivlin, M.D., and Kenneth Simons, M.D., professors of ophthalmology at the Medical College, is reported in the recent issue of Archives of Ophthalmology

"The severity of the retinal injuries is similar to that seen in nonaccidental childhood neurotrauma, or shaken baby syndrome," as per Dr. Kivlin, a pediatric ophthalmologist and lead author, who sees patients at Children's Hospital of Wisconsin. "A number of perpetrators of shaken baby syndrome have confessed to violently shaking the child, subjecting the child to severe rotational force".

The retrospective study examined ten cases of children younger than three years taken from autopsies performed by the Milwaukee County medical examiner from January 1, 1994, to December 31, 2002. All patients died in motor vehicle crashes as passengers or pedestrians. They were subjected to extremely severe forces involving rapid deceleration with a rotational, or whiplash-like, component......... Posted by: Mike      Read more         Source

May 15, 2008, 8:23 PM CT

Visual System Equipped With "Future Seeing Powers"

Catching a football. Maneuvering through a room full of people. Jumping out of the way when a golfer yells "fore." Most would agree these seemingly simple actions require us to perceive and quickly respond to a situation. Assistant Professor of Cognitive Science at Rensselaer Polytechnic Institute Mark Changizi argues they require something more - our ability to foresee the future.

It takes our brain nearly one-tenth of a second to translate the light that hits our retina into a visual perception of the world around us. While a neural delay of that magnitude may seem minuscule, imagine trying to catch a ball or wade through a store full of people while always perceiving the very recent (one-tenth of a second prior) past. A ball passing within one meter of you and traveling at one meter per second in reality would be roughly six degrees displaced from where you perceive it, and even the slowest forward-moving person can travel at least ten centimeters in a tenth of a second.

Changizi claims the visual system has evolved to compensate for neural delays, allowing it to generate perceptions of what will occur one-tenth of a second into the future, so that when an observer actually perceives something, it is the present rather than what happened one-tenth of a second ago. Using his hypothesis, called "perceiving-the-present," he was able to systematically organize and explain more than 50 types of visual illusions that occur because our brains are trying to perceive the near future. His findings are described in May-recent issue of the journal Cognitive Science......... Posted by: Mike      Read more         Source

May 12, 2008, 10:09 PM CT

High blood pressure and high cholesterol

Hypertension and high cholesterol levels appear to be risk factors for retinal vein occlusion, a condition that causes vision loss, as per a report in the recent issue of Archives of Ophthalmology, one of the JAMA/Archives journals.

Retinal vein occlusion occurs when one or more veins carrying blood from the eye to the heart become blocked, as per background information in the article. Bleeding (hemorrhage) or fluid buildup (edema) may follow, damaging vision.

Paul R.A. OMahoney, of the Royal College of Surgeons in Ireland, Dublin, and his colleagues conducted a meta-analysis of 21 previously published studies involving 2,916 individuals with retinal vein occlusion and 28,646 control participants without the condition. The scientists pooled data from all the studies and estimated the population-attributable risk, or the percentage of cases of retinal vein occlusion that could be attributed to high blood pressure (high blood pressure), diabetes and hyperlipidemia (high cholesterol).

Of patients with retinal vein occlusion, 63.6 percent had hypertension, compared with 36.2 percent of controls; those with hypertension had more than 3.5 times the odds of having retinal vein occlusion. High cholesterol levels were more than twice as common among patients with retinal vein occlusion as those without (35.1 percent vs. 16.7 percent), and those with high cholesterol levels had an approximately 2.5-fold higher risk of retinal vein occlusion. Diabetes was slightly more prevalent among those with retinal vein occlusion than among those without (14.6 percent vs. 11.1 percent)......... Posted by: Mike      Read more         Source

May 12, 2008, 9:50 PM CT

Vision therapy appears to improve visual function

A low-vision treatment program that includes a home visit, counseling, assistive devices such as magnifiers and assignments to practice using them appears to significantly improve vision in veterans with diseases of the macula (the area of the retina with the sharpest vision), as per a report in the recent issue of Archives of Ophthalmology, one of the JAMA/Archives journals.

Low vision, chronic visual impairment that limits everyday function, is one of the 10 most prevalent causes of disability in America, the authors write as background information in the article. In addition to affecting daily function, low vision increases the risk of depression, injury and an overall decline in health. Most diseases that cause low vision are not curable. In most cases, impaired vision cannot be corrected and rehabilitation is the only option for regaining lost function for the patient with low vision. Low-vision rehabilitation aims to restore functional ability, the ability to perform tasks modulated by visual impairment.

Joan A. Stelmack, O.D., M.P.H., of the Edward E. Hines Jr. VA Hospital, Hines, Ill., and the University of Illinois at Chicago College of Medicine, and his colleagues studied 126 patients (average age 78.9, 98 percent male) with low vision and diseases affecting the macula who were eligible for Veterans Affairs (VA) services. Between November 2004 and November 2006, participants were randomly assigned to one of two groups. In one, patients received a vision treatment program incorporating a low-vision examination, counseling, assistive devices such as magnifiers and five weekly sessions provided by a low-vision therapist to teach use of the assistive devices and other adaptive strategies. They were also assigned homework to ensure they used the devices outside of treatment. The other group was placed on a wait list for the treatment program and received no therapy for four months, an amount of time veterans might normally wait to receive such services......... Posted by: Mike      Read more         Source

April 21, 2008, 6:07 PM CT

Sharper imags: sports vision clinic

The standard eye chart only covers letters and numbers, but athletes need above average vision to track balls hurtling toward them at alarming speeds. To test those special skills, a University of Houston optometrist has founded the Sports Vision Performance Center, a facility where athletes perform while a strobe light is flashing, play tag with a board of lights and engage in other activities designed to improve their visual abilities.

The biggest problem that athletes face is not knowing they can potentially see much better than 20/20 vision, said Kevin Gee, a Fellow of the American Academy of Optometry and an assistant clinical professor with the UH College of Optometry. Gee opened the Sports Vision Performance Center in January to individual athletes and teams from various sports, and utilizes a range of tests to analyze what is called the visual system.

The visual system is more than just whats the smallest line on the chart you can see, Gee said. The visual system consists of a number of things, but specifically for sports, depth perception, color, speed and accuracy of movements and contrast sensitivity or the ability to detect an object off a background.

To assess these skills, Gee and his staff use instruments, such as a 3-D movie projected on a computer screen with shimmering objects that pop up to measure depth perception, a lighted batting test that can time up to one-thousandth of a second to gauge timing and accuracy, and a Dynavision board a vertical lighted peg board that determines reaction time, peripheral awareness and accuracy of movement......... Posted by: Mike      Read more         Source

April 17, 2008, 7:43 PM CT

MU researchers find clue to cataract formation

It is the No. 1 line-item cost of Medicare reimbursement and affects more than 20 million people in the United States. Cataracts, which can have devastating effects on the eye, affect 42 percent of the population between the ages of 70 and 80, and 68 percent of the population over the age of 80, as per the National Eye Institute. Now, a University of Missouri professor has identified an important step in how cataracts form. This discovery, published in a recent edition of The Journal of Biological Chemistry, could lead to a better therapy or cure for cataracts in the future.

In his study, K. Krishna Sharma, professor of ophthalmology at MU, observed that a specific type of protein begins to lose function as the eye ages. As the protein loses function, small peptides, made of 10 to 15 amino acids, start forming and accelerate cataract formation in the eye.

It is very helpful to track the formation of these peptides, Sharma said. The next step is to work on preventing their formation. If we are successful, we could delay the aging process in the eye. A ten-year delay in the onset of cataracts could decrease the number of cataract surgeries by 45 percent, thus significantly decreasing vision care cost. Currently, 1.5 million to 2 million cataract surgeries are completed yearly......... Posted by: Mike      Read more         Source

April 7, 2008, 10:50 PM CT

When poor communication pokes you in the eye

The ocular lens belongs to the optical apparatus and focuses incidental beams of light onto the retina. Now, a research team led by Professor Dr. Jochen Graw of the Institute of Developmental Genetics, of the Helmholtz Zentrum München, has been able to decipher a genetic defect responsible for small eyes and an incomplete, clouded lens in the so-called Aey12 mouse mutants. These results lead to conclusions concerning cataracts in humans, because, in this case too, the lens loses its transparency.

The development of the eye in mammals (and this naturally includes humans) is an extraordinarily complex process beginning in an early embryonic phase. The same applies also to the formation in healthy eyes of elastic and transparent lenses, which focus light beams. With the aid of the ciliary muscles, the lens can change its degree of curvature and thus set itself on varied, far distant objects. As a result, a pin sharp image is created on the retina. "As with humans, with mice too, the development of the lens starts with the formation of a spherical, hollow sac," Graw says. "That is the lens vesicle, the cover of which is surrounded by the lens epithelium, composed of a layer of cells. The vesicle is then filled in with fiber cells. In the following course of development, additional fibers originate in the equator of the lens. These scale up the diameter of the lens: a process that lasts a lifetime."........ Posted by: Mike      Read more         Source