This document summarizes the structure and functions of the eye. It discusses that the eye has three layers - outer, middle and inner. The outer layer includes the sclera and cornea. The middle layer contains the choroid, iris and pupil. The inner layer is the retina, which contains photoreceptor cells called rods and cones that detect light and convert it into electrical signals sent to the brain via the optic nerve. The document also describes additional parts of the eye like the lens and fluids that help focus light onto the retina to create vision.

1. AAFIA ASLAM
University of Central
Punjab

2. INTRODUCTION
TO PSYCHOLOGY
STRUCTURE AND
FUNTIONS OF EYE

3. THREE LAYERS OF EYES
MIDDLE
LAYER
OUTER
LAYER
INNER
LAYER
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4. PARTS OF EYES
ORBIT
SCLERA
CONJUNCTIVA
CORNEA
PUPIL
IRIS
LENS
RETINA
OPTIC NERVE
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5. 1. OUTER LAYER
• SCLERA(greek word means ’hard’)
• CORNEA
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6. Sclera: It is outermost layer of eyeball consist
of relatively tough, white layer.
Tough because pressure inside eye is double that
of atmosphere.
Conjunctiva: It is the thin transparent
membrane over sclera in the front of eye.
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7. CORNEA
The clear, curved layer in front of eye as
outermost coat appears as small bulge called
cornea.
Light enters through cornea
Serve as protective covering
Helps light to focus on retina
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8. MIDDLE LAYER
CHOROIDS
IRIS
PUPIL
Lens

9. Cont…
CHOROIDS: It is brown heavily pigmented
spongy structure.
Facilitates absorption of light.
PUPIL: Round black region in the middle of
eye is called pupil.
From cornea light enters through pupil.
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10. Cont…
IRIS: It is the circular, coloured, ciliary area of
eye that surrounds the pupil.
Colours are brown, blue, green and grey.
It controls the amount of light by changing
the size of pupil with intensity of light.
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11. Cont…
Lens:
It lies right behind the iris.
Diameter: 9mm
Thickness: 4mm
Helps focus on the things as
close up or far away
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lens

12. Inner layer
Retina
Rods
Cones
Photoreceptors

14. RETINA
It is the innermost layer of eye contains
cells called photoreceptors that sense
light.
Each photoreceptors linked to nerve fiber
which join together to form the optic
nerve.
Retina convert the image to electrical
signal towards brain.
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15. There are two types of
photoreceptors:
RODS
CONES
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16. RODS
Responsible for night and peripheral
vision.
They are sensitive to light.
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17. CONES
Responsible for the sharp
detailed , central and colour
vision.
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18. TWO FLUIDS
Aqueous humor:
From cornea to front of lens
Vitreous humor:
From back of lens to retina
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USE BIG IMAGE
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CORNEA
PUPIL
LENS
RETINA
CONES
RODS
OPTIC
NERVES
BRAIN

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