A cataract is the clouding of the eye's natural, clear lens that typically occurs with aging. In the United States, about 50% of those between the ages 65 and 74, and 70% of those over age 75, have a cataract. Women are usually affected more frequently than men.

Normal, Clear Vision
Vision Through Cataracts

There are three types of cataracts: nuclear, cortical or subcapsular. Nuclear cataracts develop in the lens nucleus (lens center) and are the type most commonly found in older patients. They can take years to develop and often give the lens center a yellow tint.

Cortical cataracts form in the lens cortex (peripheral area). They eventually extend like spokes on a wheel into the nucleus of the lens.

Subcapsular cataracts develop in the envelope of the lens, and often in the center. The onset of this type is rapid and symptoms can develop over months, rather than years.


Cataracts are painless and often progress slowly, so many years may pass before a patient experiences symptoms. If only one eye develops a cataract, the patient may never experience symptoms, as long as sight in the other eye remains stable.

Common symptoms of cataracts include blurry vision, poor night vision, halos around lights and sensitivity to bright sunlight or glare at night.



Cataract surgery is one of the most commonly performed and effective surgical procedures in the United States. Approximately 90% of patients who undergo cataract removal experience improved vision afterward. Two procedures can be used to remove a cataract: phacoemulsification and extracapsular surgery.

Phacoemulsification is the most commonly used procedure. A small incision is made on the side of the cornea and a tiny probe is inserted into the eye. This probe emits an ultrasound wave that softens and breaks up the cataract. The debris is then removed by suction.

Extracapsular surgery requires a longer incision in the cornea. The hard center of the lens is removed in one piece and the rest of the lens is suctioned out. The natural lens is then replaced with an intraocular lens (IOL), a clear, artificial lens that becomes a permanent part of the eye. The IOL is made of silicone, a plastic called PMMA, or acrylic. Light is then able to pass to the retina, improving vision. The artificial lens does not require additional care and the eye looks and feels normal.

Cataracts cannot be prevented mostly because they are age related. However, there are some things you can do to prevent them or slow down its progression including avoiding prolonged exposure to sunlight, avoid smoking and heavy alcoholic consumption, increase your diet of fruits and vegetables and take vitamin supplements.