Light entering the eye is received by the lens which focuses the light onto the retina. In some people, especially the elderly, the lens starts clouding — nobody really knows why — and starts losing its transparency. Finally it becomes so dense that no light can pass through it and the person cannot see at all with that eye. This disorder is called cataract. Formerly, the treatment consisted in removing the lens surgically and providing the person with thick glass spectacles which functioned as an artificial lens. Now there is a better method of treatment. The diseased lens is removed and an artificial lens is fitted in its place. This operation is called ‘Intraocular lens implantation’. It has done away with the need for thick spectacles after surgery. The white appearance of the diseased lens may make it look like a pearl in the eye. Because of this, cataract is called ‘motiyabind,’ pearly spot, in Hindi.