Anatomy of the eye

Every eye is surrounded by six muscles that are positioned around the eyeball and allow it to move.

The eyeball is surrounded by a white fibrous membrane known as the sclera, with the transparent cornea in front, and supported by connective tissue (conjunctiva). Adjacent to the sclera is the choroid, a layer rich in blood vessels which leads to the ring-shaped iris at the edge of the cornea. Inside the vascular tissue lies the retina with sensory and nerve cells.

It is possible to see through the iris thanks to the pupil, which dilates or contracts according to the prevailing light conditions, thereby avoiding excess exposure to light. Behind the iris is the lens, which is held in place by an elastic ligament connected to the ciliary muscle. This muscle is used to make the lens flatter or more thicker. The interior of the eye consists of gelatinous vitreous humour, which gives the eye its characteristic spherical shape.