Over half of Americans over 80 years old have cataracts or had them removed, according to the National Eye Institute. Cataracts form when the lens in the eye becomes cloudy, usually as a result of the eye’s normal aging process. Cataracts do not spread from one eye to the other but can cause vision loss in one or both eyes. Luckily, cataracts can often be treated with minimally invasive surgery.

An eye works like a camera. The lens of an eye focuses light and then sends it to the retina., which records images in the same way film does. A healthy lens is transparent, and when it becomes cloudy, the retina will receive and record blurry images. To gain some perspective on the effect of cataracts, imagine the pictures taken by a camera with a dirty lens. The photographs may still be visible, but they will likely appear less sharp. Cataracts are essentially smudged lenses in your eyes.

Most cataracts are caused by aging, but other types of cataracts may develop from different causes. Secondary cataracts are linked to an underlying health condition, such as diabetes or steroids. They can also develop after eye surgery. Traumatic cataracts are caused by an eye injury. Congenital cataracts occur at birth or during childhood. Radiation cataracts are caused by radiation exposure.

The eye lens is primarily composed of water and protein. As an individual ages, the protein can start to clump together and form cataracts. These minute masses cloud the lens and limit the light that comes through. The cataracts can grow bigger over time, blocking more light and further affecting vision. The eye ages just like the rest of the body, and cataracts may simply form due to many years of use. According to the National Eye Institute, researchers also believe additional factors like diabetes and smoking may contribute to the cataract formation. 

The cardinal sign of cataracts is cloudy or blurry vision. Beyond this telltale sign, each individual with cataracts may experience a different set of symptoms. For some people, colors may appear faded or washed out. Cataracts can also cause double vision and affect night vision. Individuals may start to find sunlight too bright or see a halo around lights. Many people with cataracts frequently need to change prescriptions for their glasses or contact lenses because of increasing cloudiness in the eye.

Cataracts may worsen over time, but surgery is typically effective, even in very advanced stages. Vision tools, such as eyeglasses or magnifying lenses, can help early cataracts. If the cataracts do not interfere with daily life, these surface measures may be adequate treatments. As cataracts advance, surgery will be required to restore vision.

There are two types of cataract surgery. Phacoemulsification, also known as phaco, involves a small incision on the eye, through which the surgeon inserts an ultrasound probe. This tiny device emits waves that disintegrate the lens, which is then suctioned out of the eye. Phaco accounts for most cataract surgeries done today, according to the National Eye Institute. Extracapsular surgery requires a longer incision, through which most of the lens is removed in one piece. In either surgery, the natural lens is replaced with an artificial lens that permanently prevents cataracts. Unfortunately, the artificial lens may not work for everyone, occasionally due to another eye disease or complications with the surgery. In this case, doctors may recommend strong eyeglasses or contact lenses to overcome the cloudy vision.