MD. SHAKIL SARKER

        Eye Human eye, in humans, specialized sense organ capable of receiving visual images, which are then carried to the brain. Physiological Significance of Eye  Create mental image of external world  Perception of : location, size , shape, color and texture of objects  If object moving: speed and direction  An image is formed on the retina by the refractive surfaces of the eye.  The light energy is transduced into electrical signal by the rods and the cones ( Photoreceptors).  The information needed to create the mental image is encoded by the neurons within the retina. Human eyeball  is roughly spherical, being a little flat from above downwards. The optic nerve enters the eyeball, a little inside the posterior pole, through the optic disc.  Tunics   From outside inward, the wall has three coats:  Fibrous coat Vascular coat Nervous coat. Fibrous coat : It has two parts:   Posterior (5/6ths) i...