As we get older, our eyes get older, too. The impact on vision can range from inconvenient to debilitating. On April 30, 2013, at MIT's annual Stratton Lecture on Aging Successfully, a panel of experts discussed three serious age-related eye problems—cataracts, glaucoma, and macular degeneration—and available treatments. The discussion was moderated by William Kettyle, M.D., medical director and gerontologist at MIT Medical.
In introducing the evening's topic, Kettyle noted that ophthalmologists, or eye specialists, typically specialize in either the front or back of the eye, and eye diseases are classified accordingly. Glaucoma and cataracts are considered front-of-the-eye problems, he said, while macular degeneration is a back-of-the-eye disease.
Glaucoma and cataracts
Panelist Bradford Shingleton, M.D, an ophthalmologic surgeon who has performed more than 50,000 glaucoma and cataract operations, began with an overview of the front of the eye. The outermost layer, the cornea, helps the eye focus, he explained. Next comes the anterior chamber, a fluid-filled space that enables light refraction. The iris and pupil work together to allow light into the eye, he continued. The pupil is a hole in the iris that allows in varying amounts of light, and the iris changes size in response. The final front-of-the-eye structure is the lens, with a shape Shingleton compared to an M&M. The lens focuses an image onto the back of the eye, functioning much like the lens of a camera.
Glaucoma occurs when fluid does not circulate around the anterior chamber, causing pressure to build up, he explained. Eye drops, the usual treatment, work either by decreasing the amount of fluid produced in the eye or by helping the fluid flow out better.
A cataract forms when proteins in the lens degrade, causing it to tighten and cloud up, he continued. The result is poor night vision and image distortion. In severe cases, cataracts appear as white spots in the eye. Damaged lens can be surgically removed and replaced with impressive results, he explained, though a patient may still need glasses.
Cataract treatment has improved greatly in recent years, Kettyle added. Surgery that required hospitalization 20 years ago is now so quick and easy that “you can be home for lunch,” he said.
Just how quick is that? Shingleton showed one of his surgery videos in real time. The procedure took six minutes.
Back-of-the-eye problems and prevention
The retina, in the back of the eye, processes images and light. Returning to the camera metaphor, panelist Jeffrey Heier, M.D., compared it to a camera's film. When the retina is damaged, you don't get a picture, said Heier, a retinal researcher and clinical instructor in ophthalmology at Harvard Medical School.
Macular degeneration is an aging-related disease that targets the retina and can result in blindness. There are two types, Heier explained, “wet” and “dry.” Wet degeneration is rare, severe, and so fast forming that it “can impact vision literally overnight,” he said. Wet degeneration occurs when blood vessels grow into the retina, and then leak and bleed. It can be successfully treated with drugs that break down the unwanted blood vessels, resulting in near-complete vision restoration. Treatment often takes years, but faster methods are under development.
Dry degeneration is the more common form of macular degeneration and develops more slowly—on the order of months to years. With the dry type, extracellular material builds up in the retina, leading to its deterioration. Currently, there is no cure.
While age-related eye diseases cannot be avoided entirely, the panelists offered some tips to reduce risk. These included wearing sunglasses to protect eyes from damaging UV rays and eating antioxidant-rich foods, such as blueberries and blackberries. Antioxidant supplements may also be helpful, Shingleton added.