More threads by David Baxter PhD

David Baxter PhD

Late Founder
Protecting Your Aging Eyes
Berkeley Wellness
February 21, 2018

It’s no secret that your view of the world can change as you get older—and it’s not just a matter of gaining a wiser perspective: Your vision can change as well, especially if you develop one of the eye diseases associated with aging. That’s why the American Academy of Ophthalmology recommends, at a minimum, a baseline eye exam in middle age and exams with increasing frequency as you get older, depending on your eye health, as advised by your eye-care specialist.

Even people who are aware of a problem may not see an eye-care specialist as often as they should. Findings from the National Health Interview Survey show that 40 percent of adults with severe visual impairment and 50 percent of those with at least some vision impairment reported that they had not seen an eye-care specialist in the previous 12 months. The survey also found that nearly 50 percent of people over age 65 with no known visual impairments had failed to see an ophthalmologist or optometrist in the previous year.
Getting a regular eye exam might even help protect your brain: An observational study published in JAMA Ophthalmology in 2017 found that older adults with loss of vision may be at higher risk for cognitive decline than those with good eyesight. This suggests that having your eyes examined on a regular basis and treating diseases that can impair your vision, such as cataracts or glaucoma, may also help preserve your mental health.

Anatomy of the eye
Numerous structures within your eye work together to make vision possible. The iris, the colored circle in the middle of the eye, is the eye’s most prominent structure. The iris is composed of smooth muscles that contract and expand to alter the size of the pupil and control the amount of light that enters the eye. Also visible from the front of the eye is the pupil, the opening in the center of the iris that resembles a large black dot. The sclera is the tough, white connective tissue that provides a protective outer layer for the eye.

Also at the front of the eye are the cornea, lens, and conjunctiva. The cornea is a transparent, dome-shaped disk that covers the iris and pupil. Beneath the cornea is the lens, a transparent, elastic structure. The cornea does about three-quarters of the work of focusing light on the retina; the lens does the rest. The conjunctiva is a thin, lubricating mucous membrane that covers the sclera and lines the inside of the eyelids.

Immediately inside the sclera is the choroid, which contains a dark pigment that minimizes the scattering of light inside the eye; it is rich in blood vessels that supply nutrients to the retina. The retina, which is made of light-sensitive nerve tissue, is the innermost layer of the eye. The retina functions like film in a camera, receiving an imprint of an image and sending it via the optic nerve to the brain. The macula, at the center of the retina, is a small area responsible for seeing what’s directly in front of you (central vision), as well as color perception and the kind of detailed vision required for reading. Between the choroid and the retina lies the retinal pigment epithelium (RPE), a layer important for vision because the cells of the retina and the RPE depend on one another metabolically.

The vitreous humor is a thick, gel-like substance that fills the back of the eyeball behind the lens. The aqueous humor is a watery fluid located in front of the lens. Together, the vitreous and aqueous humor maintain intraocular pressure (IOP), the internal pressure of the eye.

Vision smarts
Protecting this complex system—at any age—starts with little things like guarding against physical injury and being smart about the sun. Here are some eye-care tips:

  • Wear sunglasses outdoors on sunny days and a hat with a brim. Lifelong exposure to ultraviolet rays promotes cataracts and macular degeneration. Even inexpensive sunglasses block most ultraviolet rays, but for better protection look for specially labeled glasses that state they block 99-100 percent of UV rays. Sunglasses or even goggles are a good idea in the snow, too.
  • Wear goggles or safety glasses when working with power tools or dangerous chemicals that might splash, and when playing racquetball or other high-risk sports. Be wary of flying objects—twigs from a lawnmower, even a champagne cork.
  • Avoid tanning booths and sunlamps, which can cause irreversible damage to your eyes or even blindness.
  • Avoid working in bad light. Reading in bad light will not hurt your vision, but you’ll be less prone to headaches in adequate glare-free lighting—and you’ll work more efficiently and pleasurably.
  • Avoid habitual use of over-the-counter eye drops as a remedy for redness. Artificial tears, to combat dry eyes, can be used whenever needed, but preferably get a preservative-free formulation.
  • If you have prescription eye drops for one condition, don’t use them later for something else. Use prescription eye drops only as directed by a doctor.
  • Smoking endangers your eyes. So if you smoke, this is another reason to quit. Also, stay out of smoky rooms.

Problems with small print
Even if you don’t develop any of the serious eye disorders common with aging, you’re likely to find your eyes no longer work as well as they once did. Starting in the early to mid-40s, many people may have problems reading small print, whether it’s printed matter or on a computer monitor—even those who still have excellent distance vision. This condition is called presbyopia, a Greek word that literally means “old vision.” The changes are very gradual, and you won’t notice the loss until one day you find yourself squinting at a newspaper that’s held at arm’s length and still appears to be blurred, or you have trouble reading anything in a dimly lit room. By the time people reach their 50s and 60s, most will need reading glasses.

Presbyopia will gradually get worse as you age, and you will find that it’s more difficult to read small print unless you begin using corrective lenses. Specialist-prescribed glasses can cost $200, yet over-the-counter reading glasses—which cost around $20 or less—may be just as effective. When you pick out nonprescription reading glasses, be sure you have the time to try on several pairs and to read the test cards provided. You might also carry along a book or newspaper for testing. Glasses will be marked with a number ranging from 1.00 to 4.00, indicating the magnifying power. Start with a low magnification, no higher than 1.25 or 1.50, and see how well you can read the card or reading material at a comfortable distance. If that magnification isn’t sufficient, gradually move up until you find one that works.

Increase the amount of light you use for reading and other close-up activities. For instance, go from 60- to 100-watt bulbs whenever possible. Or make your computer screen brighter and the type size larger.

Medications and Your Eyes
Older people tend to take multiple medications, many of which list vision problems such as blurred vision as a potential side effect. These include corticosteroids such as prednisone, anti-arrhythmia drugs, erectile dysfunction drugs, and tamoxifen.

In general, these warnings are overly cautious, since effects on vision from prescription drugs are very rare. However, long-term use of certain medications may result in vision problems that merit monitoring by an eye doctor. Always consider drug side effects when visual symptoms develop, and be sure to tell your eye-care professional about all medications you are taking. Regular use of any drug associated with serious vision disorders merits periodic monitoring of the eyes.

Treating presbyopia
Contact an eye doctor if the signs of presbyopia begin to interfere with daily activities, to make certain you do not have a more serious condition. If your vision is changing rapidly, consult an ophthalmologist or optometrist to make sure that magnifying glasses for reading are all you need.

Several different surgical procedures are available to treat presbyopia, including using radio waves to reshape the cornea (called conductive keratoplasty, or CK). Other techniques, such as LASIK and Photorefractive keratectomy (PRK), use laser beams to reshape the cornea. In addition, the FDA has approved several devices that look like tiny contact lenses and are surgically implanted in the cornea to help improve near vision. (Your surgeon may offer monovision, which means correcting one eye for distance and the other for near so that you see with one eye at a time. However, monovision is not for everyone since it may affect depth perception.)

There are some very early reports of nonsurgical treatments such as prescription eye drops that purportedly improve the lens’s flexibility, and electrostimulation of the tiny muscles surrounding the lens. Most of these studies are very small and primarily funded by the manufacturers. These treatments cannot yet be recommended for presbyopia.

Depending on your existing vision problems, you may need bifocals or trifocals— glasses with two or three kinds of vision correction. A progressive lens—manufactured to provide a gradual change in correction from top to bottom—is another option. If you wear contact lenses, or would think about trying them, you can consider bifocal or multifocal contact lenses, though these won’t work for everyone. Another choice is monovision—wearing either one or two contact lenses so one eye is corrected for distance and the other for near. If you decide to investigate these options, discuss your needs with an experienced professional.

Seeing in the dark
Older people are susceptible to night vision problems (sometimes referred to as “night blindness”)—even if their daylight vision is okay—because of changes that occur in aging eyes. These changes include a gradual reduction in the size of the pupil (so less light hits the retina) and a decrease in the number of rods in the retina (the cells that are important for twilight and night vision). There is also a loss in contrast sensitivity (the ability to distinguish an object from its background), which makes it harder to see pedestrians, animals, and obstacles when driving. Plus, the retina’s ability to quickly adjust between bright light (as with oncoming headlights) and low-light conditions decreases with age. Diseases, such as cataracts, diabetes, or glaucoma, can also manifest themselves as night blindness.

If you have trouble seeing in low light, consult an eye-care professional, who, in addition to giving you a standard eye exam, may use special charts or other equipment to pinpoint any night vision problems. You may be a candidate for prescription night-driving glasses, even if you don’t wear glasses during the day. These other tips may also help:

  • Ask for glasses with anti-reflective coatings, which cut down on glare. High-definition lenses can give you sharper vision and also reduce glare for nighttime driving. Yellow-tinted lenses can increase contrast sensitivity, though they may also intensify glare, and any tint reduces the amount of light that reaches the eye.
  • If you are having cataract surgery, ask about getting an aspheric intraocular lens, a type of “premium” lens that improves contrast sensitivity (though these lenses are not covered by Medicare or other insurance).
  • When driving at night, make sure your headlights, windows, and mirrors are clean; use your window defoggers in inclement weather; slow your speed; and turn on the high-beams more often (but not in fog or when there are oncoming vehicles).
  • You may have to consider not driving at night if doing so puts you and others at risk for an accident.

Also see Common Eye Disorders Explained: Cataracts, Glaucoma, AMD and Eating Right for Healthy Eyes.
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