Cornea is the eye’s clear, protective outer layer and provides most of the eye’s optical power. Cornea plays a major role in focusing vision. Its curvy shape helps in refracting light from an object in a way that it falls at the perfect spot on the retina thereby enabling sharpness of vision.
Lens is a transparent convex structure that can change shape, helping the eye to focus light accurately onto the retina. Ciliary muscles surround the lens, relaxing to flatten it to image distant objects and contracting to thicken the lens to image close-up objects. Thanks to this adjustment in the lens, known as accommodation, the eye can see sharply both near and far.
Retina is a thin layer of tissue lining the back of the eye. Contains light sensitive cells and nerve fibres. Light falling on the retina produces chemical changes in the cells which then send signals along the nerve fibres via the optic nerve to the brain.
Macula is the “yellow spot” in the small (approximately 1.5 mm in diameter) central area of the retina. Contains a very high concentration of photoreceptor cells that detect light and send signals to the brain, which interprets them as images. Macula processes sharp, clear, straight-ahead vision whereas the rest of the retina provides peripheral vision.