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

March 9, 2008, 4:54 PM CT

Lasik Patients Report More Than 95 Percent Satisfaction Rate

Worldwide, an average 95.4 percent of LASIK patients are satisfied with their new vision, as per the first review of the world body of scientific literature, the American Society of Cataract and Refractive Surgery announced recently.

With 16.3 million patients having had LASIK worldwide, and more than a decade of clinical study and technological innovation behind it, LASIK is considered among the most successful elective procedures available today.

"We find that there is solid evidence in the world's scientific literature to affirm that there is an exceptionally high level of satisfaction in patients who have had LASIK surgery. While no surgery is perfect, certainly the 19 peer-evaluated studies of the 2,199 patients studied show extremely high satisfaction rates," said Richard L. Lindstrom, M.D., president of the American Society of Cataract and Refractive Surgery. "While patient satisfaction is extremely high, we recognize that there are patients who have unsatisfactory outcomes. As surgeons, we have taken the Hippocratic Oath. The well being of all of our patients is central to what we do and what we are. As such, and as the history of medicine has shown, we are committed to advancing our technology, patient selection, and surgical techniques so that we can continue to enhance the quality of our patient's lives," Lindstrom added......... Posted by: Mike      Read more         Source

March 3, 2008, 9:18 PM CT

Dry eye syndrome after LASIK surgery

Researchers at Schepens Eye Research Institute have observed that people with a certain low level of tear production are more likely to develop chronic dry eye syndrome after LASIK (laser-assisted in situ keratomileusis), laser refractive surgery to correct near- and far-sightedness than those with more plentiful tears. Their research, reported in the recent issue of Investigative Ophthalmology and Vision Science, may offer reliable prescreening criteria for ophthalmologists and patients.

These findings should help ophthalmologists determine if pretreatment is necessary before surgery or if surgery is appropriate at all for an individual, says Dr. Darlene Dartt, director of the Military Vision Research Program at Schepens Eye Research Institute and the principal investigator of the study.

Dry eye syndrome is one of the most common problems treated by eye physicians. Affecting more than 10 million Americans, it is caused by problems with the tear film responsible for lubricating the eye. While it does not cause vision loss, dry eye syndrome can be painful and severely decrease quality of life for its victims who constantly search for relief with artificial tears and other medications.

LASIK surgery uses small laser cuts to reshape the surface of the cornea, eliminating far-sightedness or near-sightedness, and the need for glasses or contacts. A number of people choose LASIK for cosmetic reasons. In recent years, thousands of military personnel have opted for LASIK surgery because it can help them see better and identify objects and people in the field more quickly. It also relieves them of the worry about lost or damaged glasses......... Posted by: Mike      Read more         Source

January 29, 2008, 10:08 PM CT

The eyes Tells It All

Using the radiocarbon dating method and special proteins in the lens of the eye, scientists at the University of Copenhagen and Aarhus can now establish, with relatively high precision, when a person was born. This provides a useful tool for forensic researchers who can use it to establish the date of birth of an unidentified body and could also have further consequences for health science research. The findings appear in the online, open-access journal PLoS ONE on January 30.

The lens of the eye is made up of transparent proteins called crystallins. These are packed so tightly together and in such a particular way, that they behave like crystals, allowing light to pass through the lens of the eye so that we can see. From conception and up until a human being is 1-2 years of age, the cells in the lens build these crystalline proteins. Once this organic construction work is done, however, the lens crystallins remain essentially unchanged for the rest of our lives. This is a fact that scientists can now put to good use.

A minute quantity of Carbon (C-12) in the carbon-dioxide content of the atmosphere contains two extra neutrons and is therefore called Carbon-14 (C-14). This isotope is radioactive, but decays so slowly and harmlessly into nitrogen, that this small carbon element, which occurs quite naturally in nature, is in no way harmful to humans, plants or animals......... Posted by: Mike      Read more         Source

January 17, 2008, 9:30 PM CT

Next Generation Optical Fibres

Researchers have discovered a way of speeding up the production of hollow-core optical fibres - a new generation of optical fibres that could lead to faster and more powerful computing and telecommunications technologies.

The procedure, described today in the journal Optics Express, cuts the production time of hollow-core optical fibres from around a week to a single day, reducing the overall cost of fabrication.

Initial tests show that the fibre is also superior in virtually every respect to prior versions of the technology, making it an important step in the development of new technologies that use light instead of electrical circuits to carry information.

These technologies include faster optical telecommunications, more powerful and accurate laser machining, and the cheaper generation of x-ray or ultra-violet light for use in biomedical and surgical optics.

"This is a major improvement in the development of hollow-core fibre technology," said Professor Jonathan Knight from the Centre for Photonics & Photonic Materials in the Department of Physics at the University of Bath.

"In standard optical fibres, light travels in a small cylindrical core of glass running down the fibre length.

"The fact that light has to travel through glass limits them in a number of ways. For example, the glass can be damaged if there is too much light......... Posted by: Mike      Read more         Source

January 17, 2008, 9:25 PM CT

Contact lenses with circuits

Movie characters from the Terminator to the Bionic Woman use bionic eyes to zoom in on far-off scenes, have useful facts pop into their field of view, or create virtual crosshairs. Off the screen, virtual displays have been proposed for more practical purposes -- visual aids to help vision-impaired people, holographic driving control panels and even as a way to surf the Web on the go.

The device to make this happen may be familiar. Engineers at the University of Washington have for the first time used manufacturing techniques at microscopic scales to combine a flexible, biologically safe contact lens with an imprinted electronic circuit and lights.

"Looking through a completed lens, you would see what the display is generating superimposed on the world outside," said Babak Parviz, a UW assistant professor of electrical engineering. "This is a very small step toward that goal, but I think it's extremely promising." The results were presented today at the Institute of Electrical and Electronics Engineers' international conference on Micro Electro Mechanical Systems by Harvey Ho, a former graduate student of Parviz's now working at Sandia National Laboratories in Livermore, Calif. Other co-authors are Ehsan Saeedi and Samuel Kim in the UW's electrical engineering department and Tueng Shen in the UW Medical Center's ophthalmology department......... Posted by: Mike      Read more         Source

January 6, 2008, 10:19 PM CT

Contact lenses purchased over Internet

Purchasing contact lenses online may save consumers time, but the process could cause more problems in the long run, as per a new study published in the recent issue of Optometry: Journal of the American Optometric Association. This research, which was conducted by Joshua Fogel, Ph.D., and Chaya Zidile of Brooklyn College, observed that individuals who did not purchase their contact lenses from an eye doctor, but from an online site or store, are potentially placing themselves at greater risk. The findings indicated that online and store purchasers (consumers who get their contacts at a wholesale club or optical chain outlet) are less likely to adhere to healthy eye care practices, as recommended by their eye doctor.

As per the Contact Lens Institute (CLI), more than 30 million individuals wear contact lenses. With the Fairness to Contact Lens Consumers Act taking effect in 2004, mandating that the prescribing eye doctor provide a copy of the contact lens prescription at no charge to the patient, consumers have the option to purchase their lenses (with a valid prescription) elsewhere. With the Internet becoming a more recognized source for health and medical information, consumers are increasingly purchasing their contact lenses online.

We observed that a pattern exists regarding the method of contact lens purchasing and following recommendations from the Food and Drug Administration (FDA), said Dr. Fogel. Those who bought contact lenses at their doctors office followed many FDA recommendations more so than those who bought contact lenses elsewhere......... Posted by: Mike      Read more         Source

December 28, 2007, 7:53 AM CT

Cost of glaucoma medications may impact treatment

In the United States, the management of glaucoma costs about $2.5 billion per year. Of the $1.9 billion in direct costs, glaucoma medications account for an estimated 38% to 52% of the total. In an article reported in the January 2008 issue of the American Journal of Ophthalmology, scientists from The Texas A&M University System Health Science Center College of Medicine, Temple, Texas; analyzed the economics of medically managing glaucoma. The yearly costs to patients of various topical glaucoma medications were calculated and significant price differences and increases in cost over time were found.

The scientists looked at four classes of pharmaceuticals; -blockers, prostaglandins, α2-agonists and carbonic anhydrase inhibitors. They compared both brand-name and generic formulations, reviewed how accurately the bottles were filled and how accurately the medications could be dispensed by patients. Using results from earlier studies, the increases in Average Wholesale Prices (AWP) were also reviewed from 1999 through 2006.

Nonselective -blockers remain the most inexpensive class of glaucoma medications. For all categories of drugs, calculated yearly cost ranged from $150.81 for generic timolol maleate 0.5% (-blocker), to $697.42 for Cosopt (combination formulation), to as high as $873.98 for a three-times-daily dose of Alphagan P 0.15% (α2-agonist). Among brand name -blockers, yearly cost ranged between $203.47 for Timoptic 0.5% and $657.24 for Betoptic S. Generic -blockers consistently were more economical than their brand-name counterparts. Yearly cost of prostaglandin analogs ranged from $427.69 for Travatan to $577.62 for Lumigan. The two carbonic anhydrase inhibitors, Azopt and Trusopt, yielded similar economic profiles. The generic selective α2-agonist brimonidine tartrate 0.2% costs approximately $352.89 and $529.34 per year for the respective two and three drops daily per eye regimens......... Posted by: Mike      Read more         Source

December 28, 2007, 7:47 AM CT

LASIK works well in highly myopic patients

Laser surgery to correct vision problems has been in use since the early part of 1990s. Photorefractive Keratotomy (PRK) is typically used to correct low to moderate myopia, while laser in-situ keratomileusis (LASIK) is preferred for high myopia corrections. Eventhough over 18 million LASIK procedures have been performed worldwide, there is still some controversy regarding the maximum correction possible and efficacy with this technique. In an article reported in the January 2008 issue of the American Journal of Ophthalmology, scientists from Miguel Hernandez University, Medical School, Alicante, Spain; and Ankara University School of Medicine, Ankara, Turkey; report on a study of high myopia patients ten years after LASIK surgery. The findings show that LASIK for myopia over -10 D is a safe and effective procedure in the long-term.

196 high myopic eyes of 118 patients, preoperatively needing at least 10 diopter (10 D) corrections to achieve 20/20 vision, were reviewed ten years following surgery. Uncorrected vision was 77% of best-corrected vision (BSCVA) before surgery. BSCVA improved 1 line. Only 5% of eyes lost more than 2 lines of BSCVA and 40% avoided the use of glasses. 119 (61 %) of eyes were within 2.00 Diopters at 10 years. Only 2 eyes (1%) developed corneal ectasia. The retreatment rate was 27%......... Posted by: Mike      Read more         Source

November 29, 2007, 10:42 PM CT

New treatment for age-related macular degeneration

With 8 million people at high risk for advanced age-related macular degeneration, scientists from Harvard and Japan discovered that the experimental drug, endostatin, may be the cure. A research report reported in the December 2007 issue of The FASEB Journal, describes how giving endostatin to mice significantly reduced or eliminated abnormal blood vessel growth within the eye, which is ultimately why the disease causes blindness.

Our study provides intriguing findings that may lead to a better therapy of age-related macular degeneration, said Alexander Marneros, the first author of the report, but clinical studies in patients with age-related macular degeneration are still necessary.

In this study, scientists describe testing the effects of endostatin on mice lacking this naturally occurring substance. The mice without endostatin were about three times more likely to develop advanced age-related macular degeneration (AMD) than normal mice. Then the scientists administered endostatin to both sets of mice. In the mice lacking endostatin, the number of abnormal blood vessels that cause AMD were reduced to normal levels. In control mice with normal levels of endostatin, the number of abnormal blood vessels were practically undetectable.

With Baby Boomers reaching advanced ages, new therapys are desperately needed to keep age-related macular degeneration from becoming a national epidemic, said Gerald Weissmann, MD, Editor-in-Chief of The FASEB Journal. This research provides hope for those at risk for blindness, and it gives everyone another glimpse of how investments in molecular biology will ultimately pay off in terms of new therapys and cures......... Posted by: Mike      Read more         Source

November 7, 2007, 9:32 PM CT

How the brain sends eyeballs bouncing

All vision, including reading this sentence, depends on a constant series of infinitesimal jumps by the eyeball that centers the retina on target objectswords or phrases in the case of reading. Such jumps, or saccades, are critical to vision because only the small central region of the retina, called the fovea, produces the clear image necessary for perception. Such saccades take place several times a second and are generated within a brain region known as the frontal eye field (FEF).

In studies with monkeys, Robert Schafer and Tirin Moore have taken an important step in understanding how circuitry of the FEF generates saccadeswith the FEFs attentional circuitry governing the motor circuitry that produces saccades. The scientists published their findings in the November 8, 2007, issue of the journal Neuron, published by Cell Press.

In a preview of the paper in the same issue of Neuron, Stefan Everling wrote that the scientists findings are exciting, because they demonstrate that attention and action interact more closely in the FEF than previously thought, and they suggest a mechanism by which attention can modulate saccade motor commands. Everling is at the University of Western Ontario in Canada.

In their experiments, Schafer and Moore took advantage of a well-known optical phenomenon involving the influence of the motion of a drifting grating on saccades that target the grating. The moving grating causes a motion-induced bias of saccades; for example, if the eye makes a saccade to a grating that is drifting upward, that saccade to the grating is biased to land higher than it would if the grating were stationary......... Posted by: Mike      Read more         Source