Retina

The light-sensitive membrane that lines the back inner surface of the eye, and on which images are cast by the cornea and lens. The retina contains specialized nerve cells (rods and cones) that convert light energy into nerve impulses. The impulses travel from the rods and cones through other cells in the retina and along the optic nerve to the brain. The rods respond to very dim light and cones are responsible for colour vision. The retina can be affected by congenital and genetic disorders, such as colour vision deficiency and Tay–Sachs disease. It can also be infected, injured (see retinal detachment; retinal tear), or affected by tumours such as retinoblastoma. Other disorders affecting the retina include diabetes mellitus and retinal vein occlusion.