Four Things Ophthalmologists Want You to Know About Your Eyes

Most people only think about their eyes when something already hurts. Yet several of the most common risks to eye health are also the easiest to prevent, once the everyday habits behind them are clear: how eyes are protected from the sun, how contact lenses are worn, how screens are used, and how often a comprehensive exam is scheduled.

Yes, your eyes can get sunburned

Too much sun does not only damage skin. Prolonged or intense exposure to ultraviolet light can burn the surface of the eye in much the same way it burns skin, a condition doctors call photokeratitis. It produces redness, pain and sensitivity similar to a scratched cornea, and is common after a day at the beach or on the ski slopes, where UV exposure is especially high. Symptoms usually resolve within a day or two, though lubricating drops, cool compresses, rest and occasionally antibiotics may be needed.

The cornea, the eye's clear outer layer, can regenerate, but repeated sun exposure without protection over the years raises the risk of certain types of cataracts, a clouding of the eye's lens that impairs vision. Sunglasses or goggles that block both UVA and UVB rays are the most effective safeguard and are worth wearing in any setting where you also apply sunblock.

Contact lenses: two habits to break

Contact lenses should be removed before entering any body of water, including the sea, lakes and swimming pools. Water can carry bacteria, organisms and chemicals that are difficult to treat once trapped against the eye, and a contact lens creates an enclosed space between the eyeball and the lens where such organisms can multiply. The safest option is to wear prescription swimming goggles; where that is not possible, daily disposable lenses worn under goggles and discarded immediately afterwards carry a lower, though not eliminated, risk.

Sleeping in contact lenses carries a similar risk. Tear production and oxygen delivery to the cornea both fall during sleep, and soft lenses can dehydrate and tighten slightly overnight, causing them to adhere to the eye's surface. Removing an adhered lens can tear the cornea's outer layers, leaving the eye more vulnerable to infection. Lenses should be removed before sleep regardless of how late the hour.

Why screens leave your eyes feeling dry

The eyes normally blink around fifteen times a minute, a rate that keeps the surface of the eye moist. Concentrated screen use can cut that rate by half, which is why extended periods at a computer or phone often bring on dry, irritated eyes.

The 20-20-20 rule is a simple corrective: every twenty minutes, look at something at least twenty feet away for twenty seconds. The break encourages a return to a normal blink rate and eases strain. Preservative-free artificial tears can also help, since preservatives in some over-the-counter drops can themselves irritate the eye with frequent use.

An eye exam can catch more than eye problems

A comprehensive eye exam typically includes dilation, in which drops are used to widen the pupil so the back of the eye can be examined directly. This gives doctors a clear view of the retina and its blood vessels, which can carry early signs of conditions well beyond the eye itself, including diabetes, high blood pressure, high cholesterol and cardiovascular disease, and in some cases has led to the detection of certain cancers or brain tumours.

Exams also screen for glaucoma, a group of diseases that damage the optic nerve and can lead to permanent vision loss. Glaucoma frequently develops without noticeable symptoms in its early stages, which is why routine screening, rather than waiting for symptoms to appear, is what allows it to be caught early.

For adults with no symptoms or known risk factors, ophthalmologists recommend a baseline comprehensive exam at age 40, followed by a checkup every one to four years depending on age. From age 65 onward, an exam every one to two years is advised, regardless of whether symptoms are present.

Source: The New York Times, «4 Things Ophthalmologists Wish You Knew About Your Eyes», Jancee Dunn