The human eye is a sensory organ that reacts to visible light and allows humans to see. It has three coats that enclose optically clear fluids and a vitreous body. The outer coat includes the cornea and sclera, the middle coat contains blood vessels and the iris, and the inner coat lines the inside of the eye. The eye contains structures like the iris, lens, retina, and optic nerves that help focus light and transmit visual signals to the brain. Common eye defects include myopia where distant objects are blurry, hypermetropia where near objects are blurry, and presbyopia where the ability to focus on close objects is gradually lost with age.

1. Structure Of Eyes And Its Defects
Physics Holiday Homework

2. Human Eye
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 for various purposes
including seeing things, keeping balance, and maintaining
circadian rhythm.
The eyeball is not a simple sphere but can be viewed as the
result of fusing a small portion of a small, strongly curved
sphere with a large portion of a large, not so strongly curved
sphere. The small piece, occupying about one-sixth of the
whole, has a radius of 8 mm (0.3 inch); it is transparent and is
called the cornea; the remainder, the scleral segment, is
opaque and has a radius of 12 mm (0.5 inch). The ring where
the two areas. Thus, on looking directly into the eye from in
front one sees the white sclera surrounding the cornea;
because the latter is transparent one sees, instead of the
cornea, a ring of tissue lying within the eye, the iris. The iris
is the structure that determines the colour of the eye. The
centre of this ring is called the pupil.
The eye is made up of three coats, which enclose the optically
clear aqueous humour, and vitreous body. The outermost coat
consists of the cornea and the sclera; the middle coat contains
the main blood supply to the eye and consists, from the back
forward, of the choroid, the ciliary body, and the iris.

3. .
Parts Of Eye
Sclera: It is the outer covering, a
protective tough white layer called
the sclera (white part of the eye).
Cornea: The front transparent part of
the sclera is called the cornea. Light
enters the eye through the cornea.
Iris: A dark muscular tissue and ring-
like structure behind the cornea is
known as the iris. The colour of the
iris actually indicates the colour of the
eye. The iris also helps regulate or
adjust exposure by adjusting the iris.

4. .
Lens: Behind the pupil, there is a
transparent structure called a lens. By the
action of ciliary muscles, it changes its
shape to focus light on the retina. It
becomes thinner to focus on distant
objects and becomes thicker to focus on
the nearby objects.
Retina: It is a light-sensitive layer that
consists of numerous nerve cells. It
converts images formed by the lens into
electrical impulses. These electrical
impulses are then transmitted to the brain
through optic nerves.
Optic nerves: Optic nerves are of two
types. These include cones and rods.

5. Defects Of Human Eye
Myopia
 Nearsightedness (myopia) is a common vision
condition in which near objects appear clear,
but objects farther away look blurry. It occurs
when the shape of the eye or the shape of
certain parts of the eye causes light rays to
bend (refract) inaccurately.

6. Hypermetropia
Hypermetropia
 Hypermetropia is also referred to as
hyperopia or long-sightedness or far-
sightedness. Hypermetropia is the condition
of the eyes where the image of a nearby
object is formed behind the retina. Here, the
light is focused behind the retina instead of
focusing on the retina.

7. Presbyopia
Presbyopia
 Presbyopia is the gradual loss of your eyes'
ability to focus on nearby objects. It's a
natural, often annoying part of aging.
Presbyopia usually becomes noticeable in
your early to mid-40s and continues to
worsen until around age 65

8. Thank You
Name: Hemanshi Verma
Class: 10th-B
Roll No: 24