December 2, 2010

Two New Breakthroughs for Aging Eyes

(Ivanhoe Newswire) -- Two new studies provide hopeful information for those at risk of age-related macular degeneration (AMD) and glaucoma.

The first study was conducted by researchers at Johns Hopkins School of Medicine's Wilmer Eye Institute to determine if a regular consumption of omega-3 rich seafood had an influence on the risk of developing AMD, the leading cause of blindness for Caucasians in the U.S.  Since retinas naturally contain large amounts of omega-3s, the nutrient is believed to be integral for healthy eyes.  The study would serve to add evidence to similar past studies, such as the Age-Related Eye Disease Study.

Led by Sheila K. West, PhD and part of the Salisbury Eye Evaluation (SEE) study, the researcher's surveyed 2,391 seniors aged 65 to 84 over one year to collect information regarding their diets. Next, they organized the 1,942 individuals without AMD into a control group and separated the remaining participants into early, intermediate-stage, and advanced-stage AMD groups - the latter marked by the conditions of neovascularization (irregular blood vessel growth and bleeding) or geographic atrophy - both of which can lead to severe visual impairment and blindness.

The researchers then analyzed their data in hopes of finding a connection between seafood intake and the development of AMD.

"Our study corroborates earlier findings that eating omega-3-rich fish and shellfish may protect against advanced AMD," Dr. West was quoted as saying.  "While participants in all groups, including controls, averaged at least one serving of fish or shellfish per week, those who had advanced AMD were significantly less likely to consume high omega-3 fish and seafood."

The study contained a few unfavorable variables, such as the presence of participants who were affected by other AMD risk factors such as smoking and obesity, but its conclusions were consistent with the findings of previous studies.

The second study was conducted at the Bascom Palmer Eye Institute at the University of Miami's Miller School of Medicine, and looked at a non-invasive, new method of early glaucoma detection.  By measuring the performance of nerve cells in the retina called retinal ganglion cells (RGCs), which often become dysfunctional following the onset of glaucoma, the researchers believed they would be able to discover the condition at an earlier stage than had been previously possible.

To test this, lead researchers Mitra Sehi, PhD, David Creenfield, MD, and their team used a pattern electroretinogram optimized for glaucoma screening (PERGLA), which assesses changes in RGC functionality by observing their electrical activity in the retina.  They performed two PERGLA evaluations on 47 individuals who had undergone drainage surgery for intraocular pressure (IOP), the first evaluation being completed before the procedure and the other being completed three months following it.
The PERGLA results showed that RGC dysfunction had been reversed in all cases following successful drainage surgery.  Furthermore, the patients made improvements on central visual field tests.  However, Dr. Sehi warns readers that her team's conclusions should be interpreted carefully until more in-depth studies are performed.  She believes that longitudinal studies directed at finding the relationship between lowered IOP and increased RGC reaction should be conducted, and that more PERGLA tests should be run to prove its effectiveness as a biomarker for glaucoma.

SOURCE: American Academy of Ophthalmology, December 2010