" Polychromatic luster" is a feature of

Ans. d (Complicated cataract) (Ref. Basak's ophthalmology 2nd ed., 181)COMPLICATED CATARACTS# It is a complication of any protracted intraocular inflammation, especially heterochromia, chronic iridocyclitis, retinal vasculitis, and retinitis pigmentosa.# Complicated cataract results from a disturbance of the lens metabolism due to inflammatory or degenerative diseases.# The result is a "pumice-like posterior subcapsular cataract" that progresses axially toward the nucleus.# Vision is much impaired even in early stage, due to position of the opacity near nodal point of eye.# The opacity usually commences in posterior cortex in the axial plane (posterior cortical cataract).# The opacity appears grayish with "bread-crumb" appearance in oblique illumination.# This form of cataract produces extreme light scattering.# On slit lamp, the opacity shows a characteristic rainbow display of colors, the polychromatic luster.# Rx: Operative and visual prognosis in complicated cataract is usually poor.Note: Riders ("spoke wheel") are seen in lamellar cataract, which is the most common type of congenital cataract.