Cataracts and Lifestyle

Cataract surgery is the most frequently performed surgery in the United States. This is due to the fact that everyone will eventually develop a cataract. However, not everyone will need to undergo cataract surgery; cataract surgery is reserved for patients who have a symptomatic decrease in best-corrected vision that also affects their ability to perform activities of daily living (ADLs). ADLs is a term used to describe a “laundry list” of activities; it refers to the activities you either need or want to perform in your life. ADLs may include cooking, cleaning, laundry, golfing, exercising, reading, working on the computer, driving, and performing on the job, among other things. Your ADLs are specific to you. In other words, if you have difficulty performing the tasks you either need or want to do on a regular basis, because your vision is decreased due to a cataract, then you may be a candidate for cataract surgery. It is not uncommon for patients to have a decrease in vision due to cataract formation that does not bother them. In these patients, cataract surgery is not necessary. Occasionally, there are reasons to have a cataract removed that are not necessarily related to visual function.

One of the most important criteria for the formation of normal vision is a clear visual axis. This means the line extending from the front of the cornea to the retina must be clear in order for light to transmit properly. Any type of obstruction in the visual pathway will affect the propagation of light onto the retina. If light does not reach the retina unimpeded, normal visual images cannot be formed. Consider, for a moment, how your vision is affected if you have dirt or a smudge on your glasses or car windshield. This is an obstruction in the visual pathway that causes blurry vision. A similar process occurs with the formation of a cataract. It is simply a clouding of the crystalline lens inside the eye. Over time, as the lens becomes cloudy, two things happen: Firstly, it loses its ability to transmit and focus light. As the lens becomes more and more cloudy−that is to say, as the cataract gets worse and worse−vision will become increasingly blurry. Secondly, the lens loses its ability to change shape in the process of accommodation. As the cataract forms, the lens also becomes less flexible, and loses its ability to alter its shape in order to change the focus of light. Accommodation is the process by which we focus from distance to near. Loss of accommodation as you age is what leads to the need for reading glasses in most people.

Ultimately, cataracts cause light to scatter within the eye. When this occurs, light never becomes properly focused, and clear visual images cannot be formed. Some of these light rays will still reach the retina, but they will be disorganized. They do not reach a focal point in the center of the retina; therefore, they do not contribute in any way to useful vision.

The following illustrations demonstrate the changes that occur in the eye as a cataract forms, as well as the changes in the way light propagates within the eye as a result of a cataract. One can see from these illustrations how a cataract can directly lead to blurry vision.

Illustration of normal eye anatomy, including a clear crystalline lens.

Illustration showing a cataract in place of a clear crystalline lens.

Illustration showing how light is focused on the retina in a normal, emmetropic eye.

Illustration showing how light is scattered by a cataract.

©Vision Information Services, LLC, Mooresville, NC 2012