Contributor: Gordon K. Klintworth
The nuclear cataract is a type of cataract that affects the lens nucleus. In the nuclear sclerotic cataract [cataract - nuclear sclerotic] the hardened central lens nucleus appears yellowish or brown. The color results from an accumulation of urochrome. The colored lens absorbs blue light distorting color vision [color vision defect]. An increase in the index of refraction of the causes lenticular myopia [myopia - lenticular]. Nuclear sclerosis is characterized microscopically by an increased eosinophilia and homogeneity of the lens nucleus, which lacks the artifactitious clefts observed in normal lens cortex. Nuclear cataracts sometimes contain oval birefringent crystals of calcium oxalate. Nuclear cataracts are a feature of Nance-Horan syndrome.