Feb 13, 2013

Appreciating the Beauty of the Retina

Science Education

Even though the best retinal researchers still don’t understand the science completely, everyone can appreciate the basics, including how to keep their retinas as healthy as possible.

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An image of a mouse retina captured by Dr. Luca Della Santina, University of Washington.

The retina is an amazingly elegant and complex tissue lining the back of the eye. Retinas make vision possible; without them, we can't see. But most people never think about their retinas — unless, of course, they have a retinal condition affecting their vision.

I'll always remember my first Foundation Fighting Blindness conference, when I heard Dr. Dean Bok, of the University of California, Los Angeles, discuss the retina's design and how it worked. I was new to the field and just learning. Dr. Bok opened his presentation by saying that, as a student, he was "seduced" by the beauty of retinal science. By the end of his impassioned talk, I, too, was hooked.

And, now, I'm always excited to speak and write about this magical piece of tissue. Even though the best retinal researchers still don't understand the science completely, I think everyone can appreciate the basics, including how to keep their retinas as healthy as possible.

How the Retina Works

So what does the retina do? In simple terms, it converts light into electrical signals that are sent through the optic nerve to the brain, where they're interpreted as vision. Put another way, the retina is like film in a camera — for those of us old enough to remember when film had to be loaded into a camera.

The photoreceptors — a.k.a., rods and cones — are the elongated retinal cells (like antennae) that transform light into electricity through a complex biochemical process fueled by vitamin A. Rods provide night and peripheral vision. Cones, which are concentrated in the macula (central retina), enable people to perceive details, colors and objects. Approximately 125 million photoreceptors are packed into each human retina.

While the retina is small — it's a circular tissue just 35 millimeters in diameter (a little bigger than a quarter) and half a millimeter thick — it's a real workhorse. In fact, the retina processes more oxygen for its size than any other tissue or organ in the body, including the heart and lungs. Not only does it provide vision during waking hours, the tips of photoreceptors are shed, disposed and regenerated during sleep. For the retina, there's always work to be done.

Inherited retinal diseases often originate in photoreceptors, but there are a number of other cell types in the retina that can be affected. These other cells may provide nutrition, waste disposal and image-processing.

Keeping the Retina Healthy

Whether or not you have a retinal disease, there are things you can do to keep the retina healthy and functioning optimally. As we always say at the Foundation, what's good for your heart is good for your eyes.

First and foremost, don't smoke. It is the most significant modifiable risk factor for age-related macular degeneration, and research has shown that just one cigarette's worth of nicotine reduces retinal sensitivity.

Also, eat lots of colorful vegetables and fruits, which are rich in antioxidants, such as lutein and zeaxanthin. In fact, these antioxidants are present in the retina, especially in the macula. They help protect the retina from light damage and daily wear-and-tear.

Docosahexaenoic acid (DHA), a healthy fat, is another important nutrient that protects retinal cells and keeps them functioning well. DHA is abundant in coldwater fish, such as tuna, salmon, herring and sardines. It is also available in fish oil or vegetarian supplements.

Protecting your eyes from bright sunlight is also important. Always wear sunglasses that screen out UV rays and a wide-brimmed hat when in the sunshine.

And, finally — again, whether or not you have a retinal disease — see an eye doctor immediately if you experience sudden changes in vision. The sooner you get help, the better chance the problem can be resolved and vision saved or restored.

Conditions like wet age-related macular degeneration and retinal detachments can be treated. And while a doctor can't yet treat an inherited retinal disease, there are related complications, such as cystoids macular edema (swelling), which may be resolved with a medication.

For More Information

To learn more about the retina and emerging treatments, visit the Foundation's website and return regularly to Eye on the Cure. Both sites are chock-full of articles and posts on the latest advancements. Also, feel free to ask questions in the comments section of each blog post or send them to info@fightingblindness.org. It's our pleasure to keep you informed.