Cataracts

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Medical Author:

David A. Paine, MD

Medical Author:

J. Bradley Randleman, MD

J. Bradley Randleman, MD

Dr. Randleman received his BA degree from Columbia University in New York City. He earned his MD degree from Texas Tech University in Lubbock, Texas, where he was elected to the Alpha Omega Alpha Medical Honor Society. He completed his residency training at Emory University, serving as Chief Resident in his final year. He then completed a fellowship in Cornea/External disease and refractive surgery at Emory University.

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Medical Editor:

Melissa Conrad Stöppler, MD, Chief Medical Editor

Melissa Conrad Stöppler, MD, Chief Medical Editor

Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

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• Cataract Overview
• Cataract Causes
• Types of Cataracts
• Cataract Symptoms
• When to Seek Medical Care
• Questions to Ask the Doctor
• Exams and Tests
• Cataract Treatment
• Surgery
• What Are the Different Types of Intraocular Lenses Implanted After Cataract Surgery?
• What Should One Expect Prior to and on the Day of Surgery?
• What Should One Expect After the Surgery?
• What Are Potential Complications of Cataract Surgery?
• Prevention
• Outlook
• For More Information
• Web Links
• Multimedia
• Synonyms and Keywords
• Authors and Editors
• Read more on Cataracts from Healthwise
• Viewer Comments: Cataracts - Symptoms

Cataracts are changes in clarity of the natural lens inside the eye that gradually degrade visual quality. The natural lens sits behind the colored part of the eye (iris) in the area of the pupil, and cannot be directly seen with the naked eye unless it becomes extremely cloudy. The lens plays a crucial role in focusing unimpeded light on the retina at the back of the eye. The retina transforms light to a neurologic signal that the brain interprets as vision. Significant cataracts block and distort light passing through the lens, causing visual symptoms and complaints.

The term cataract is derived from the Greek word cataractos, which describes rapidly running water. When water is turbulent, it is transformed from a clear medium to white and cloudy. Keen Greek observers noticed similar-appearing changes in the eye and attributed visual loss from "cataracts" as an accumulation of this turbulent fluid, having no knowledge of the anatomy of the eye or the status or importance of the lens.

Cataract development is usually a very gradual process of normal aging but can occasionally occur rapidly. Many people are in fact unaware that they have cataracts because the changes in their vision have been so gradual. Cataracts commonly affect both eyes, but it is not uncommon for cataracts in one eye to advance more rapidly. Cataracts are very common, affecting roughly 60% of people over the age of 60, and over 1.5 million cataract surgeries are performed in the United States each year.

Experts have estimated that visual disability associated with cataracts accounts for over 8 million physician office visits a year in the United States. This number will likely continue to increase as the proportion of people over the age of 60 rises. When people develop cataracts, they begin to have difficulty doing activities they need to do for daily living or for enjoyment. Some of the most common complaints include difficulty driving at night, reading, participating in sports such as golfing, or traveling to unfamiliar areas; these are all activities for which clear vision is essential.

The lens is made mostly of water and protein. Specific proteins within the lens are responsible for maintaining its clarity. Over many years, the structures of these lens proteins are altered, ultimately leading to a gradual clouding of the lens. Rarely, cataracts can present at birth or in early childhood as a result of hereditary enzyme defects, and severe trauma to the eye, eye surgery, or intraocular inflammation can also cause cataracts to occur earlier in life. Other factors that may lead to development of cataracts at an earlier age include excessive ultraviolet-light exposure, diabetes, smoking, or the use of certain medications, such as oral, topical, or inhaled steroids. Other medications that are more weakly associated with cataracts include the long-term use of statins and phenothiazines.

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