What are the main parts of the eyes?
Cornea: “the window of the eye” which provides focusing power when light enters. It forms a protective dome over the internal eye and is comprised of 5 layers of tissue with the outer layer, called the epithelium, providing most of the protection. This is what is covered by a contact lens, when worn. Pupil: the “black circle” seen in the centre of the iris. The pupil controls the amount of light entering the eye-ie. In a bright environment, the pupil becomes smaller to allow less light through and in a dark environment, the pupils expands to allow more light to reach the back of the eye. Iris: the coloured part of the eye (ie. Blue/brown/green/hazel). The primary function is to control the size of the pupil, achieved through contraction or expansion of the muscles of the iris. The muscles in the iris become artificially and temporarily relaxed when dilating drops are used for testing. Lens: the clear structure hidden behind the pupil, is another focusing device used to provide fine-tun
