100%(2)2 out of 2 people found this document helpful
This preview shows page 9 - 10 out of 10 pages.
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 zonulesare 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.Cataractderives from the Latincataractameaning "waterfall" and the Greekkataraktesand katarrhaktes, from katarasseinmeaning "to dash down" (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, cataractahad the alternate meaning "portcullis",so it is also possible that the name came about through the sense 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.In dialect English a cataract is called a pearl, as in "pearl eye" and "pearl-eyed".