The human eye works much like a camera does: it takes in light from the environment and uses that light to form an image. When light reaches the human eye, it first passes through a crystalline lens, which focuses the light towards the interior of the eye. This lens is controlled by the ciliary muscles, a pair of muscles which adjust the lens to allow us to see at different distances. The light is then focused onto the retina, a layer of tissue which contains light-sensitive cells which react to incoming light. This allows the retina to “capture” the image produced by the surrounding environment and send that data to the brain to be processed as visual data.

As people grow older, many parts of their body begin to weaken, and the eyes are no exception. As humans age, it often becomes more difficult for them to focus their vision and distinguish different colors. They also often need more light to properly see, and more time to adjust to sudden changes in brightness (such as when leaving a dark room and entering a bright one). Such conditions are considered a normal part of aging, and is often treated with prescription lenses or contact lenses. Actual visual loss, on the other hand, is not considered a natural part of aging and occurs due to multiple medical disorders. Such disorders include cataracts, where the lens of the eyes become clouded, diabetic retinopathy, where the blood vessels in the retina bleed and cause blurred vision, glaucoma, a group of diseases which damage the optic nerve and can cause sudden loss of eyesight, and Age-related Macular Degradation (AMD), where the center of the retina, the macula, deteriorates and causes a loss of vision.

This begs the question, “How can I maintain my eyesight?” There are multiple ways to safeguard your eyesight and minimize your risk of eye-related diseases. One way is to avoid smoking. Smoking has been shown to increase the risk of multiple eye-related disorders, such as AMD. Maintaining a healthy and nutritious diet has also been shown to significantly decrease one’s risk of eyesight loss. Another way to preserve your eyesight is to frequently wear sunglasses or sunhats when outside. This prevents damage caused by excessive exposure to sunlight. Contrary to popular belief, staring at a computer screen does not damage one’s eyes.

The eyes, like any other part of the body, can become strained from overexertion. This strain, by itself, won’t necessarily damage the eyes, but it will tire them out and, as a result, tire the rest of the body out as well. There are many common causes of eyestrain, many of which are fairly easy to avoid. For instance, staring at a computer screen for a long, uninterrupted period of time, will cause eyestrain. A good way to prevent eyestrain is to take 5-minute breaks when using the computer for long periods of time, or simply dim the computer screen by adjusting its brightness setting. One myth about eyestrain is that wearing contacts or glasses causes it. Wearing glasses or contacts does not negatively impact your vision, and attempting to read without them only causes excessive eyestrain. Another common source of eyestrain is reading in dim light. Always make sure to have an adequate source of light when reading for an extended period of time

There are some myths regarding how one can improve their eyesight. A common myth is that eating carrots helps improve eyesight. This myth has some truth to it. Carrots contain vitamin A, which is beneficial to the eyes. However, there are many other fruits and vegetables which contain vitamin A and other beneficial vitamins such as vitamin C and vitamin E, both of which are better at preventing eye disorders. Furthermore, while eating such foods will help preserve eyesight, doing so will not correct basic vision problems or improve eyesight. Another myth is that one can “exercise” their eyes in order to prevent vision degradation or improve vision. This stems from the role the ciliary muscles play in allowing humans to see at varying differences, and the belief that by “exercising” these muscles, one can thus correct or prevent problems such as nearsightedness. However, vision depends on many other factors, such as the shape of the lens or the health of one’s eye tissues. Such factors cannot be significantly altered through eye exercises, and thus, eye exercises are not a reliable way to correct vision problems.

Eyesight is a very important sense for humans to have, one that many take for granted until they lose it. Many believe vision loss is just a natural part of growing old. However, with proper eye care, one can maintain good eyesight even late in life.

References:

“Vision Changes as We Age: What's Normal, What's Not?” University of Utah Health, www.healthcare.utah.edu/healthfeed/postings/2016/09/vision.changes.php.

Publishing, Harvard Health. “Safeguarding Your Sight.” Harvard Health, www.health.harvard.edu/healthbeat/safeguarding-your-sight.

Kazilek. “How Do We See?” Kazilek, 1 July 2015, www.askabiologist.asu.edu/explore/how-do-we-see.