Cataracta brunescens result due to deposition of

Nuclear senile cataract: The usual degenerative changes are intensification of the age- related nuclear sclerosis associated with dehydration and compaction of the nucleus resulting in a hard cataract. It is accompanied by a significant increase in water insoluble proteins. However, the total protein content and distribution of cations remain normal. There may or may not be associated deposition of pigment urochrome and/or melanin derived from the amino acids in the lens. The nucleus may become diffusely cloudy (greyish) or tinted (yellow to black) due to deposition of pigments. In practice, the commonly observed pigmented nuclear cataracts are either amber, brown (cataracta brunescens) or black (cataracta nigra) and rarely reddish (cataracta rubra) in colour. Ref:- A K Khurana; pg num:- 176,178