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Archives Of Ophthalmology News Blog From Medicineworld.Org


June 19, 2007, 5:08 AM CT

Nanoparticle Offers Promise for Treating Glaucoma

Nanoparticle Offers Promise for Treating Glaucoma
Photo: Jerry Klein.
Glaucoma affects millions of people and if left untreated can cause blindness
A unique nanoparticle made in a laboratory at the University of Central Florida is proving promising as a drug delivery device for treating glaucoma, an eye disease that can cause blindness and affects millions of people worldwide.

"The nanoparticle can safely get past the blood-brain barrier making it an effective non-toxic tool for drug delivery," said Sudipta Seal, an engineering professor with appointments in UCF's Advanced Materials Processing and Analysis Center and the Nanoscience Technology Center.

The findings will be published in an article appearing in the June 28 issue of the Journal of Physical Chemistry C.

Seal and colleagues from North Dakota State University note in the article that while barely 1-3 percent of existing glaucoma medicines penetrate into the eye, earlier experiments with nanoparticles have shown not only high penetration rates but also little patient discomfort. The miniscule size of the nanoparticles makes them less abrasive than some of the complex polymers now used in most eye drops.

Seal and his team created a specialized cerium oxide nanoparticle and bound it with a compound that has been shown to block the activity of an enzyme (hCAII) believed to play a central role in causing glaucoma.

The disease involves abnormally high pressure of the fluid inside the eye, which, if left untreated, can result in damage to the optic nerve and vision loss. High pressure occurs, in part, because of a buildup of carbon dioxide inside the eye, and the compound blocks the enzyme that produces carbon dioxide.........

Posted by: Mike      Read more         Source


May 17, 2007, 7:14 PM CT

Soft Contacts Designed for Cone-Shaped Cornea

Soft Contacts Designed for Cone-Shaped Cornea
Geunyoung Yoon (PHOTO CREDIT: University of Rochester)
Custom-designed contacts improved vision for subjects with keratoconic eyes and offer hope of nonsurgical therapy instead of corneal transplants. University of Rochester scientists describe the custom design techniques and results of visual acuity tests in a paper published in April in Optics Letters.

Keratoconic eyes are rare but disabling. From the side, the eyes look more pointed or cone-shaped than round. The apex shift from visual axis in the cornea causes people with the condition to see halos and double and triple images. About 1 in 2,000 people suffer from the disease, commonly in both eyes.

"The condition shows up in a relatively small population, but it causes huge optical problems," says Geunyoung Yoon, assistant professor in the Departments of Ophthalmology and Biomedical Engineering, the Center for Visual Science, and the Institute of Optics. "These people have problems so severe, they can't tolerate glasses. They can't take laser vision correction because they have a very thin cornea around the apex, so it's not an option. The only available therapy is to wear hard contact lenses or corneal transplant with a donored cornea if the disease is severe. And with the corneal transplant, there is a rejection rate".

All three subjects reported their vision significantly improved with the custom-designed soft contact lenses.........

Posted by: Mike      Read more         Source


May 7, 2007, 10:58 PM CT

Many older Americans not treated for glaucoma

Many older Americans not treated for glaucoma
Fort Lauderdale, Fla. -- Almost one-third of older Americans diagnosed with primary open angle glaucoma (POAG) are not treated medically or surgically for the condition as per a research studyto be presented at the Association for Research in Vision and Ophthalmology (ARVO) Annual Meeting in Fort Lauderdale, Fla. The presentation will be held on Monday, May 7, 2007, at 11:45 a.m. in the Grand Floridian H of the Greater Fort Lauderdale/Broward County Convention Center.

The study is the first investigation of glaucoma-therapy use in the U.S. to utilize longitudinal data from a nationally representative sample of Medicare patients. The scientists examined trends in glaucoma medicine use and surgeries among adults aged 65 and older by analyzing data collected from 1992 through 2002 as part of the Medicare Current Beneficiary Survey (MCBS). A total of 3,020 MCBS participants were identified as having diagnosed POAG.

A major finding of this study is that, on average, 30 percent of Medicare beneficiaries with POAG did not use any glaucoma medicine and did not undergo any type of glaucoma-related surgery in a given study year. Among those patients who did use glaucoma-related medications, the classes of prescription eye drops used changed over the study period, with a substantial increase in the use of prostaglandin analogues.........

Posted by: Mike      Read more         Source


April 10, 2007, 6:00 PM CT

Eye diseases for great painters

Eye diseases for great painters
After writing two books on the topic of artists and eye disease, the Stanford University School of Medicine ophthalmologist decided to go one step further and create images that would show how artists with eye disease actually saw their world and their canvases. Combining computer simulation with his own medical knowledge, Marmor has recreated images of some of the masterpieces of the French impressionistic painters Claude Monet and Edgar Degas who continued to work while they struggled with cataracts and retinal disease.

The results are striking:

In Marmor's simulated versions of how the painters would most likely have seen their work, Degas' later paintings of nude bathers become so blurry it's difficult to see any of the artist's brush strokes. Monet's later paintings of the lily pond and the Japanese bridge at Giverny, when adjusted to reflect the typical symptoms of cataracts, appear dark and muddied. The artist's signature vibrant colors are muted, replaced by browns and yellows.

"These simulations may lead one to question whether the artists intended these late works to look exactly as they do," said Marmor who has long had interest in both the mechanics of vision and the vision of artists. "The fact is that these artists weren't painting in this manner totally for artistic reasons".........

Posted by: Mike      Read more         Source


March 15, 2007, 6:28 PM CT

Video Games Improve Vision

Video Games Improve Vision
As per a new study from the University of Rochester, playing action video games sharpens vision. In tests of visual acuity that assess the ability to see objects accurately in a cluttered space, game players scored higher than their non-playing peers.

"Action video game play changes the way our brains process visual information," says Daphne Bavelier, professor of brain and cognitive sciences at the University of Rochester. "After just 30 hours of training, people who normally don't play video games showed a substantial increase in the spatial resolution of their vision, meaning they could see small, closely packed letters more clearly."

Most of the factors that affect a normal person's ability to read an eye-chart are optical (size of the eye, the shape/thickness of the cornea and lens) and video games will not change those factors. However, there are some types of visual deficits that aren't optical in nature but are instead neural. "It is our hope that video game training can help these people," says Bavelier.

Only certain games create this effect; first-person action games. Shooting games, such as Unreal Tournament, improved vision. More sedate games, such as the puzzle game Tetris, showed no effect. "When people play action games, they're changing the brain's pathway responsible for visual processing," says Bavelier. "These games push the human visual system to the limits and the brain adapts to it. That learning carries over into other activities and possibly everyday life".........

Posted by: Mike      Read more         Source


February 19, 2007, 8:11 PM CT

Those Who Once Were Blind Can Learn To See

Those Who Once Were Blind Can Learn To See Pawan Sinha, associate professor of brain and cognitive sciences and the senior author on a paper.
How does the human brain "learn" to see? If the brain is deprived of visual input early in life, can it later learn to see at all?

MIT scientists are exploring those questions by studying some unique patients--people who were born blind, or blinded very young, and later had their sight restored.

Doctors have long believed that children who were blind during a "critical period" early in life had little hope of learning how to see even if vision were later restored, so they were reluctant to offer potentially risky surgical therapys such as cataract removal to children older than 5 or 6.

However, in a recent case study, the MIT scientists observed that a woman who had her vision restored at the age of 12 performed almost normally on a battery of high-level vision tests when they studied her at the age of 32. The study appears in the recent issue of Psychological Science.

The new research "shows that the brain is still malleable" in older children, says Pawan Sinha, senior author and associate professor of brain and cognitive sciences at MIT. This knowledge could benefit thousands of blind children around the world, especially in developing nations, who were previously believed to be too old to receive eye therapy.

The MIT scientists found their case study subject in India, where childhood blindness is a huge problem, and where Sinha recently launched a humanitarian initiative, Project Prakash, to help expand the reach of eye care facilities.........

Posted by: Mike      Read more         Source


February 13, 2007, 8:48 PM CT

Genetic Testing Of Degenerative Eye Disease

Genetic Testing Of Degenerative Eye Disease
ANN ARBOR, Mich. Genetic testing for eye disease is providing vital information about complex retinal diseases, particularly when used to confirm a clinicians diagnosis.

In a newly published review of such tests that were conducted over a five-year period at the University of Michigan Kellogg Eye Center, researchers were able to confirm a clinicians diagnosis in half of the cases. The testing took place in the laboratory of Radha Ayyagari, Ph.D., director of Kelloggs Ophthalmic Molecular Diagnostic Laboratory.

In the recent issue of Archives of Ophthalmology, Ayyagari and her colleagues report on 350 genetic tests conducted since 1999, when the U-M Ophthalmic Molecular Diagnostic Laboratory became one of the first laboratories in the nation to receive government approval for ophthalmic testing under the Clinical Laboratory Improvement Amendment (CLIA). For each test described in the current study, researchers analyzed one or more of eight genes known to cause diseases of the retina.

Of the 350 tests, 266 were performed to confirm a clinicians diagnosis, by far the most common use of genetic testing for eye disease. Another 75 tests sought to determine whether an individual was a carrier of a disease, and nine tests were used to predict the likelihood that an individual with a family history of a given eye disease would go on to develop it.........

Posted by: Mike      Read more         Source


January 9, 2007, 8:25 PM CT

Letting The Blind See

Letting The Blind See
Kristina Narfstrom, a University of Missouri-Columbia veterinary ophthalmologist, has been working with a microchip implant to help blind animals "see." As per Narfstrom, the preliminary results are promising.

"About one in 3,500 people worldwide is affected with a hereditary disease, retinitis pigmentosa, that causes the death of retinal cells and, eventually, blindness," Narfstrom said. "Our current study is aimed at determining safety issues in regard to the implants and to further develop surgical techniques. We also are examining the protection the implants might provide to the retinal cells that are dying due to disease progression with the hope that natural sight can be maintained much longer than would be possible in an untreated patient."

Narfstrom, the Ruth M. Kraeuchi-Missouri Professor in Veterinary Ophthalmology, is working primarily with Abyssinian and Persian cats that are affected with hereditary retinal blinding disease. The cat's eye is a good model to use for this type of research because it is very similar to a human eye in size and construction, so surgeons can use the same techniques and equipment. Cats also share a number of of the same eye diseases with humans. The Abyssinian cats that Narfstrom is working with typically start to lose their sight when they are around one or two years old and are completely blind by age four.........

Posted by: Mike      Read more         Source


December 22, 2006, 5:26 AM CT

LASIK and LASEK eye surgery

LASIK and LASEK eye surgery
A study comparing the safety, effectiveness and reliability of LASIK and LASEK has found no clinically significant differences between the two types of laser eye surgery.

The study, led by a University of Illinois at Chicago researcher, is reported in the December 2006 issue of the American Journal of Ophthalmology.

"Eventhough there have been a number of studies of the safety and efficacy of both types of laser surgery, there has not been a large study directly comparing the outcomes of the two procedures," said Dr. Dimitri Azar, field chair of ophthalmologic research and professor and head of ophthalmology and visual sciences at UIC.

In the retrospective, case-matched study, eyes that had undergone laser eye surgery were matched for many measures, including visual acuity and astigmatism; 122 LASIK-treated eyes were matched for all measures with 122 LASEK-treated eyes from a review of the charts of 2,257 eye surgeries performed by Azar. All patients' outcomes included a follow-up of at least six months.

"We observed that eventhough there were some differences in the visual and refractive results that favor the LASEK procedure, the differences were not clinically significant," said Azar. "These results are in line with prior smaller studies that we evaluated comparing the procedures."........

Posted by: Mike      Permalink         Source


December 10, 2006, 9:17 PM CT

New Treatments To Prevalent Eye Diseases

New Treatments To Prevalent Eye Diseases
Scientists at The Scripps Research Institute have discovered a method of repairing and normalizing blood vessels in the eye through the use of stem cells derived from bone marrow. These findings may point to a new approach for developing treatments for a certain type of eye diseases.

The research, led by Scripps Research Professor Martin Friedlander, was published online November 16 in The Journal of Clinical Investigation.

In the new study, the team injected immature white blood cells from bone marrow-myeloid progenitors-into eyes with an abnormal vasculature (network of blood vessels) in a mouse model developed to mimic certain human disorders. The researchers found that not only did the progenitor cells migrate to avascular areas of the retina, but once there they differentiated into cells called microglia that actively promoted vascular repair.

"From a purely basic science perspective, this is a novel observation," says Friedlander. "Even more importantly, the study introduces the idea that bone marrow-derived myeloid progenitors could be used to treat ischemic eye disease-an entirely new paradigm".

While there had been increasing interest in microglia among scientists in the field, this is the first time microglia have been shown to contribute to the promotion of vascular repair in any organ, including the eye. These results suggest that it might be possible to use cells derived from a patient's own bone marrow or cord blood to treat such eye diseases as diabetic retinopathy or retinopathy of prematurity (ROP).........

Posted by: Mike      Permalink         Source



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