Could eye drops be an alternative treatment to cataract surgery?
Researchers have discovered a compound that reverses cataracts and is soluble enough to be used as eye drops, Science reports.
If left untreated, cataracts can lead to blindness. The only treatment is surgery to remove the lens, which is commonplace in the United States but not available in many developing countries.
"Cataracts in humans have been around as long as humans have been around, and this is the first time in history that they're using a nonsurgical approach for their removal," says Andrew Morgenstern, O.D., chair of AOA's New Technology Committee and a consultant with Booz Allen Hamilton whose current assignment is with the Vision Center of Excellence at Walter Reed National Military Medical Center in Bethesda, Maryland.
Crystallins in our eyes work as chaperones to help prevent the clumping of proteins, or aggregation of insoluble amyloids, that cause cataracts, but crystallins can become overwhelmed as we age. Previous research had shown that lanosterol, which belongs to a group of chemical compounds called sterols, reversed cataracts. However, lanosterol was not water-soluble enough to be included in an eye drop solution and had to be injected into the eye.
In this new study, researchers tested 32 additional sterols, focusing on Compound 29, which not only dissolved the amyloids in a lab dish but also prevented the formation of new protein clumps. Researchers then confirmed that Compound 29 reversed hereditary- and age-related cataracts in mice and in human lens tissue removed during cataract surgery.
Not an immediate option
One limitation of the study is that it was a mouse study, says Sue Lowe, O.D., chair of the AOA Health Promotions Committee who practices in Laramie, Wyoming. You can't ask mice about their visual acuity.
"Every individual still interprets what they see differently," she says.
Dr. Lowe explains that a cataract might appear cloudy to the doctor of optometry, yet the patient says he or she can see well. On the other hand, another patient may have a clearer-looking cataract, yet complain about poor eyesight.
An animal model also means the research isn't "going anywhere fast," Dr. Morgenstern says. But it could be a stepping stone for research of future treatments.
The concept of eye drops as cataract treatment isn't new, Dr. Lowe says. A product was developed in Russia using a compound called N-acetylcarnosine in eye drops to treat cataracts. It's available in the United States as a dietary supplement but is not approved by the U.S. Food and Drug Administration. It was patented by the research team in Russia, where most of the studies have been conducted.
Drs. Morgenstern and Lowe agree that cataract surgery will likely remain the primary treatment in the United States, but an eye drop that improves cataracts could be a boon to the developing world, even if it doesn't eliminate the cataract altogether.
"Sometimes the best treatment you can get for a patient is an improvement and not necessarily a complete cure," Dr. Morgenstern says. "If you can take an individual with a 20/200 cataract and you can get them to 20/40 best-corrected vision with a simple eye drop, that's pretty amazing stuff."
The AOA follows all research and new technology closely, including potential new cataract treatment. Although these eye drops are an interesting development, more research is needed regarding their influence on visual health. For more information or help for better vision, please visit the AOA's diet and nutition page.
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