A partial or complete opacification, or clouding over, of the lens. A term used to describe any color perception deficiency. Few people lack total color recognition, and the most common deficiency is the inability to distinguish between red and green. Light-sensitive cells densely congregated in the central portion of the retina. They account for precise seeing and function at higher levels of illumination than the other light receptors, the rods.
Color vision is a function of the cones.
An inflammation of the conjunctiva. It covers the iris and lens and is continuous with the white sclera. It provides most of the eye's refracting power, focusing light as it passes onto the retina. A term used by eye doctors for eye drops used for diagnostic purposes during an eye examination. When light enters the eye, they cast moving shadows on the retina.