STRUCTURE OF THE
HUMAN EYE
AND ITS FUNCTIONS

THE HUMAN EYE
 The human eye is an organ which reacts to light and pressure. As a sense organ,
the mammalian eye allows vision.

PARTS OF THE HUMAN EYE
 The front part of the eye includes:
 Iris, the coloured part
 Cornea, a clear dome over the iris
 Pupil, the black circular opening in the iris that lets light in
 Sclera, the white of the eye

EYE ANATOMY

IRIS
 Coloured part of the eye
 Controls the amount of light entering the eye

CORNEA
 Transparent covering of the front of the eye
 Allows for the passage of light into the eye and functions as a fixed lens
 Focuses light entering the eye

PUPIL
 Black hole in iris
 Light enters through the pupil
 Pupil size is controlled by iris muscles

THE REFRACTIVE STRUCTURES
 These structures bend the light so that a clear image is produced
 They are,
 Tears
 Cornea
 Lens

LIDS AND LASHES
 Main function is the protection of the eye
 They also help to distribute tears which wash and lubricate the eyes

THANK YOU

SCLERA
 A tough white skin (made of tissue) that covers all of the eyeball except the cornea
 Supports eyeball and provides attachment for muscles

RETINA
 Internal membrane
 Contains light receptive cells (rods and cones)
 Converts light waves into electrical signals

OPTIC NERVE
 Transmits electrical impulses from retina to the brain
 Creates blind spot
 Brain takes inverted image and flips it so we can see

BLIND SPOT
 Sit about a foot away from your screen
 Close your left eye
 Stare at the circle
 Move closer to the screen, then farther
away
 Keep doing this until the plus sign
disappears
 When it disappears, you found your right
eye’s blindspot

THANK YOU THANK YOU