THE EYE

BACK TO HOME PAGE

PHOTORECEPTORS

RODS

CONES

RHODOPSIN

MECHANISM

VITAMIN A

DEFECTS OF THE EYE

REFERENCES

The below diagram shows the basic anatomy of the human eye:

Cornea: the transparent part at the front of the eye that refracts light entering the eye onto the lens.

Lens: a transparent structure behind the pupil that refracts incoming light and focuses it onto the retina. The lens is able to change shape in order to improve the focus.

Iris: This is the coloured part of the eye that controls the amount of light that enters the eye, it is able to contact and dilate in order to control the size of the pupil depending on the light intensity.

Sclera: the outer white part of the eye that protects the inner structures.

Retina: this is the light sensitive layer inside the eye that contains light sensitive photoreceptive cells called rods and cones. These cells change light into sight by converting light into electrical impulses. These electrical messages are sent from the retina to the brain and interpreted as images.

Optic nerve: this leaves the eye at the optic disk and transfers all the visual information to the brain.

Conjunctiva: a transparent vascular membrane that lines the inside of the eyelids and extends over the front of the white part of the eye (the sclera).

Aqueous humor: this fluid circulates the front part of the eye, it provides nourishment and helps maintain the eye pressure.

Vitreous humor: the clear gel in the centre of the eye that helps the eye to maintain its spherical shape.