Privileged Immunity for The Human Eye

The visual system in humans is unique and privileged in many ways. The reflected light from the object passes through the transparent cornea and lens gets converted into electrical signals by the retina, which is richly supplied with blood, passing through the optic nerve to the brain where these signals are processed and form the image. Because the eye must maintain transparency, there are ocular blood barriers present at different levels. And since there is no supply of the blood, the immune system must be unique. Another feature for the eye to see the objects, it remains always in touch to environment it requires extra protection to infections therefore the eye is provided a unique immune system designated as “immune privilege (IP)”-- the term coined by Sir Peter Medawar, in the 1948.