This is a well explained PPT on topic 'eye'

2. POSITION AND SIZE OF EYE
STRUCTURE OF EYE
DEFINITION OF EYE
ACCOMDATION POWER
DEFECTS AND CORRECTION

3.  The human eye is a sensory organ, part of
the sensory nervous system, that reacts to
visible light and allows humans to use visual
information which is then taken to brain and
is analysed there.
 जीवधारिय ों का वह अोंग है ज प्रकाश क
े प्रति
सोंवेदनशील है।

5.  Humans have two eyes, situated on the left
and the right of the face. The eyes sit in
bony cavities called the orbits, in the skull.
 The size of the eye differs among adults by
only one or 2 millimetres.

6. ORBIT

7.  The eye is made up of three coats, or layers,
enclosing various anatomical structures.
 The outermost layer, known as the fibrous
tunic, is composed of the cornea and sclera,
which provide shape to the eye and support
the deeper structures.
 The middle layer, consists of the choroid,
ciliary body, pigmented epithelium and iris.
 The innermost is the retina

9.  Iris: A dark muscular tissue and ring-like structure
behind the cornea is known as the iris. The iris also
helps regulate or adjust exposure by adjusting the
iris.
 Pupil: A small opening in the iris is known as a pupil.
Its size is controlled with the help of iris.
 Lens: Behind the pupil, there is a transparent
structure called a lens. By the action of cilliary
muscles, it changes its shape to focus light on the
retina.
 Retina: It is a light-sensitive layer that consists of
numerous nerve cells. It converts images formed by
the lens into electrical impulses.
 Optic nerves: Optic nerves are of two types. These
include cones and rods.

11. Some of the common defects
of vision are:
(i) Myopia or near-sightedness
(ii) Hypermetropia or far-
sightedness
(iii) Presbyopia

12.  Myopia is commonly known as near-
sightedness. In this condition, the person can
see the objects nearby but cannot see
distant objects clearly.
 Correction : When a concave lens of suitable
power is used, it assists in focusing the image
onto the retina.

14.  Hypermetropia is commonly known as far-
sightedness. In this condition, the person can
see objects at a distance but cannot see
nearby objects clearly.
 Correction : Using spectacles with a
converging lens imparts additional focusing
power and thus helps form the image on the
retina.

16.  PresbyopiaWe know that along with age, the
power of the accommodation factor to adjust
the focal length also decreases.
 Correction : This condition can be corrected
by using proper eyeglasses or contact lenses.