To your health: Your aging eyesight
By Dan Coden, M.D., Scripps Health
If you’re around age 40 and have noticed that you need to hold small print farther and farther away in order to read it clearly, it is not just your imagination — nor are your arms shorter than they used to be. After age 35, everybody starts to develop a type of age-related vision disorder called presbyopia, which means “aging eye” in Greek. As the eyes age, they lose the ability to focus up close, making activities such as reading a book or typing a text message more difficult. People often try to compensate by holding objects as far away as possible to see them more clearly, but their arms are only so long.
Presbyopia is associated with the process of refraction in the eye. Refraction is the bending of light as it passes through an object; in the eye, the cornea and lens bend or refract the rays of light that come in through the pupil so that they focus directly on the retina at the back of the eye. The retina converts the light into messages that are sent through the optic nerve to the brain, where they are communicated as the images we see. As the lens of the eye ages, it becomes harder and less flexible and loses its ability to precisely focus light onto the retina; instead, it focuses light behind the retina, which blurs close vision. In addition, aging also weakens muscle fibers within the eye, which makes it more difficult to focus on close objects. The result is presbyopia.
Nearly everyone experiences some degree of presbyopia after age 35. In addition to difficulty reading small print or seeing objects close to you clearly, symptoms may include headaches and eye strain. The symptoms vary in severity —some people may notice considerable changes in their close vision, while others may not notice as significant a difference.
While there is no cure for presbyopia, there are ways to manage it. The first step is to have a professional eye examination with an ophthalmologist or optometrist. The exam should include dilation of the eye, a painless procedure which enables the doctor to examine your retina for age-related eye diseases which often may not be detected otherwise. In addition to a regular vision test, you will be asked to read small print at a close distance to help determine the degree of presbyopia and how to address it. Eyeglasses designed for close work (often called readers or cheaters) are the most common solution for presbyopia. Reading glasses are sold at many drug and department stores in varying strengths, and have become quite fashionable. No prescription is required, but it is a good idea to have your ophthalmologist or optometrist determine which strength is best for you before you purchase them, as even a slightly weaker or stronger prescription than necessary may cause eye strain or headaches.
People who already have other vision problems such as nearsightedness (myopia), farsightedness (hyperopia), and blurred vision due to irregular corneal shape (astigmatism) do also develop presbyopia. Contact lens wearers may just need reading glasses, or may wear a lens for distance vision in one eye and a lens for close vision in the other, a process called monovision.
People who already wear eyeglasses may switch to bifocals, which have two different prescriptions in one lens. The top part of the lens corrects for distance vision, while the lower part is for close vision. Another option, progressive bifocals, have a gradual transition between the two prescriptions.
There is much interest in a surgical treatment for presbyopia, and current research looks to be promising. Ophthalmologists look forward to an FDA approved cure in the near future.
Should you notice any changes in your vision, it is very important to see your eye professional to rule out serious problems.
Daniel Coden, M.D., is an ophthalmologist with Scripps. “To Your Health” is brought to you by the physicians and staff at Scripps. For more information or a physician referral, call 1-800-SCRIPPS or visit www.scripps.org.