Cataracts

Learning to see better in life and baseball

With a little practice on a computer or iPad—25 minutes a day, 4 days a week, for 2 months—our brains can learn to see better, according to a study of University of California, Riverside baseball players reported in the ...

Feb 17, 2014
popularity 0 comments 0

Spotting eye problems in pets

Pets don't have to read an eye chart to keep a driver's license or don prescription glasses to see the tiny text on a smartphone. But they still need eye care. In fact, animals experience many of the same ...

Oct 13, 2014
popularity 0 comments 0

A cataract is a clouding that develops in the crystalline lens of the eye or in its envelope (lens capsule), varying in degree from slight to complete opacity and obstructing the passage of light. Early in the development of age-related cataract, the power of the lens may be increased, causing near-sightedness (myopia), and the gradual yellowing and opacification of the lens may reduce the perception of blue colors. Cataracts typically progress slowly to cause vision loss, and are potentially blinding if untreated. The condition usually affects both eyes, but almost always one eye is affected earlier than the other.

A senile cataract, occurring in the elderly, is characterized by an initial opacity in the lens, subsequent swelling of the lens and final shrinkage with complete loss of transparency. Moreover, with time the cataract cortex liquefies to form a milky white fluid in a Morgagnian cataract, which can cause severe inflammation if the lens capsule ruptures and leaks. Untreated, the cataract can cause phacomorphic glaucoma. Very advanced cataracts with weak zonules are liable to dislocation anteriorly or posteriorly. Such spontaneous posterior dislocations (akin to the historical surgical procedure of couching) in ancient times were regarded as a blessing from the heavens, because some perception of light was restored in the cataractous patients.

Some children develop cataracts, called congenital cataracts, before or just after birth; these are usually dealt with in a different way to cataracts in adults.

Cataract derives from the Latin cataracta meaning "waterfall" and that from the Greek καταράκτης (kataraktēs) or καταρράκτης (katarrhaktēs), "down-rushing", from καταράσσω (katarassō) meaning "to dash down" (from kata-, "down"; arassein, "to strike, dash"). As rapidly running water turns white, the term may later have been used metaphorically to describe the similar appearance of mature ocular opacities. In Latin, cataracta had the alternate meaning "portcullis" and it is possible that the name passed through French to form the English meaning "eye disease" (early 15c.), on the notion of "obstruction". Early Persian physicians called the term nazul-i-ah, or "descent of the water"—vulgarised into waterfall disease or cataract—believing such blindness to be caused by an outpouring of corrupt humour into the eye.

This text uses material from Wikipedia licensed under CC BY-SA

Latest Spotlight News

Mathematical model seeks functional cure for HIV

(Medical Xpress)—Individuals with the natural ability to control HIV infection in the absence of treatment are referred to as elite controllers (ECs). Such individuals maintain undetectable viral loads ...

Finding the body clock's molecular reset button

An international team of scientists has discovered what amounts to a molecular reset button for our internal body clock. Their findings reveal a potential target to treat a range of disorders, from sleep ...

Neurons constantly rewrite their DNA

Johns Hopkins scientists have discovered that neurons are risk takers: They use minor "DNA surgeries" to toggle their activity levels all day, every day. Since these activity levels are important in learning, ...

Researchers bring order to big data of human biology

A multi-year study led by researchers from the Simons Center for Data Analysis (SCDA) and major universities and medical schools has broken substantial new ground, establishing how genes work together within ...

New breast cancer gene identified

A new breast cancer gene has been identified in a study led by Women's College Hospital (WCH) researcher Dr. Mohammad Akbari, who is also an assistant professor with the Dalla Lana School of Public Health ...

Hate to diet? It's how we are wired

If you're finding it difficult to stick to a weight-loss diet, scientists at the Howard Hughes Medical Institute's Janelia Research Campus say you can likely blame hunger-sensitive cells in your brain known ...