ANATOMY OF THE NORMAL EYE

ANATOMY OF THE NORMAL EYE

 

Let's take a look at the human eye and explore the parts

and functions.

 

The eye consists of three layers referred to as 'TUNICS.'

 

 

1.  The FIBROUS TUNIC--This is the outside, tough protective layer.

This is made up of the (a.) Anterior --1/6 of the CORNEA--the cornea is clear and

                                       is avascular 

 

 

                                 (b.) Posterior --5/6 SCLERA--the sclera is opaque and

                                        vascular

 

2. The VASCULAR TUNIC--This is the middle layer which contains blood vessels.

This is made up of (a.) CHOROID--This is the brownish tissue that supplies blood  to the outer layer of the retina--this is held in place by the Vitreous Humour

 

 

                            (b.)  CILIARY BODY--black tissue that connects the choroid

                                    with the iris--this produces Aqueous Humour.

 

                            (c.)  IRIS--Circular structure of various colours --controls

                                   diameter of the pupil

 

3. The NERVOUS TUNIC--This is on the inside of the eye and is composed of receptor cells.

 

 

The CORNEA is transparent and covers the iris, pupil and anterior chamber.  Most of the eye's power comes from the cornea which has five layers.

 

The LENS or CRYSTALLINE LENS is the natural lens in the eye which is transparent and biconvex.  The lens is responsible for focusing light rays on the retina.  The lens is suspended by ligaments called zonules attached between the ciliary body.

 

AQUEOUS HUMOR--This is the clear, watery fluid that fills the space between the back surface of the cornea and the front surface of the Vitreous.  This liquid is produced by the ciliary process and nourishes the cornea, iris and lens.

 

VITREOUS HUMOR--This is the transparent, colourless jelly-like mass that fills the back two-thirds of the eyeball, between the lens and the retina.