Presbyopia – the Aging Eye
Presbyopia (which literally means “aging eye”) is an age-related eye condition that makes it more difficult to see very close.
When you are young, the lens in your eye is soft and flexible. The lens of the eye changes its shape easily, allowing you to focus on objects both close and far away.
After the age of 40, the lens becomes more rigid. Because the lens can’t change shape as easily as it once did, it is more difficult to read at close range. This normal condition is called presbyopia.
Since nearly everyone develops presbyopia, if a person also has myopia (nearsightedness), hyperopia (farsightedness) or astigmatism, the conditions will combine. People with myopia may have fewer problems with presbyopia.
Unlike other refractive errors such as nearsightedness (myopia), farsightedness (hyperopia) and astigmatism, presbyopia is caused by an age-related process that leads to the eye’s lens losing its flexibility.
It is generally believed that as we age, changes in the lens’s proteins make the lens more rigid and less flexible over time. Also, muscles surrounding the lens may lose their elasticity. As the lens becomes less flexible and able to change shape as easily as it used to, the eye has a harder time focusing on close objects. This is why people over age 40 often find themselves holding reading material farther away to be able to see it clearly.
Some of the signs and symptoms of presbyopia include eyestrain, headaches or feeling tired from doing up-close work. One of the most obvious signs of presbyopia is the need to hold reading materials at arm’s length in order to focus properly.
The symptoms of hyperopia (farsightedness) and presbyopia are similar, however, they are caused by different things. Hyperopia is a refractive error that occurs when the eye is shorter than normal or has a cornea (clear front window of the eye) that is too flat. As a result, light rays focus beyond the retina instead of on it. Generally, this allows you to see distant objects clearly but near objects will appear blurred. While hyperopia is usually present from birth, presbyopia develops later — usually around age 40.
Your eye doctor can diagnose presbyopia as part of a comprehensive eye examination. In addition to checking for other eye problems, he or she will determine your degree of presbyopia by using a standard vision test.
Your doctor will use an instrument that the measures the amount of refractive error you have and helps determine the proper prescription to correct it. You will try out several corrective prescriptions to determine which one will offer the best presbyopia correction for you.
There is no best method for correcting presbyopia. The most appropriate correction for you depends on your eyes and your lifestyle. You should discuss your lifestyle with your ophthalmologist to decide which correction may be most effective for you.
Reading glasses are a very common and easy way to correct presbyopia symptoms, and are typically worn just during close work such as reading, sewing, etc. These “readers” are easily purchased at drug stores and other retail stores. You can also choose higher-quality versions prescribed by your eye doctor. If you decide to pick out a pair of reading glasses from the store, it is important that you select the weakest pair that will allow you to read newspaper-size print without difficulty.
If you wear contact lenses, your eye doctor can prescribe reading glasses that can be worn with your regular contacts to help you adjust to detailed, close-up work.
Eyeglasses with bifocal or progressive lenses are another common method of correcting presbyopia. Bifocal lenses have two different points of focus. The upper part of the eyeglass lens is set for distance vision, while the lower portion of the lens has a prescription set for seeing close work. Progressive lenses are similar to bifocal lenses, but they offer a more gradual visual transition between the two prescriptions, with no visible line between them.
Another option for correcting presbyopic vision is multifocal contact lenses. Just as bifocal lenses have two levels of corrective power, multifocal contact lenses create multiple levels of corrective power.
Another way to correct presbyopia with contact lenses is monovision, in which one eye has a contact set for distance, and the other has a contact set for near vision. The brain learns to adapt to using one eye or the other for different tasks.
Because the eye’s lens continually changes with age, you will need to have your prescription increased over time as well. Your eye doctor can prescribe a stronger prescription as needed to help you with up-close vision.
Written by Kierstan Boyd