Eye Physiology and Anatomy

Eye is the organ of sight situated in the orbital cavity. It is almost spherical in shape and is about 2.5 cm in diameter. The volume of an eyeball is approximately 7cc. The space between the eye and the orbital cavity is occupied by fatty tissue. The bony wall of the orbit and the fat helps to protect the eye from injury.

Structurally the two eyes are separate but they function as a pair. It is possible to see with only one eye, but three- dimensional vision is impaired when only one eye is used specially in relation to the judgment of distance.

Structure of the Eye:

The eyeball has three layers namely:

• The outer fibrous layer - Sclera and cornea
• The middle vascular layer – Iris, ciliary body & choroids
• The inner nervous tissue layer – Retina

Interior of the Eyeball:

The structures inside the eyeball are:

• Aqueous humor
• Lens
• Vitreous

Accessory Structures of the Eye:

• Eyebrows
• Eyelids & eyelashes
• Lacrimal apparatus
• Extraocular muscles of the eye