Which morphological type of cataract is most visually handicapping: March 2011
Ans. C: Posterior subcapsular Posterior subcapsular cataract results in loss of ability to see objects in bright sunlight and blinded by light of oncoming headlights when driving at night as constriction of pupil cuts off peripheral vision from non-cataractous area Posterior subcapsular cataract An opacity in the lens positioned just anterior to the posterior lens capsule and characterized by the posterior migration of lens epithelial cells from the lens bow. Etiology The lens is composed largely of crystallins which aggregate in cataract formation. There are many associations with posterior subcapsular cataracts including chronic vitreal inflammation, ionizing radiation, trauma and prolonged use of coicosteroids. Clinical Findings Younger individuals may be affected and the symptoms include complaints of glare at night with bright headlights or poor vision with accommodation. Near vision may often be more affected than distance vision. Usually the earliest sign is a focal dot-like area on the posterior capsule or a reflective sheen. With progression, translucent opacities appear (the swollen Wedl cells) on the posterior capsule that have been likened to a "cloth of gold" or "fish eggs". Posterior capsular cataract is associated with coical degeneration and nuclear sclerosis. Gross An opacity that is central and irregular is the most frequent finding Treatment Surgical removal of the cataract generally restores vision.
Coical
Nuclear
Posterior subcapsular
Zonular