1. EYE ANATOMY
Conjunctiva:
The conjunctiva is a thin, mucous membrane that
lines the eyelids and sclera, but not the cornea.The
conjunctiva offers some protection to the eye, but
its primary function is to lubricate the outer layer
of the eye.
Cornea:
The cornea is sometimes referred to as the
“window of the eye.” It provides most of the
focusing power when light enters your eye. The
cornea is composed of 6 layers of tissue. The outer
layer (the epithelium) is the eye’s protective layer.
This layer is made up of highly regenerative cells
that have the ability to grow back within 3 days,
and therefore, allow for fast healing of superficial
injuries. Most of the inner layers provide strength
to the eye. The laser vision correction procedure is
performed on this part of the eye.
Sclera:
This is the ‘white part’ that we see in people’s
eyes. The sclera’s purpose is to provide structure,
strength and protection to the eye. Extraocular
muscles are attached to sclera which help in the
movement of eyeball.
Pupil:
The pupil is the ‘black circle’ that you see in
people’s eyes. The primary function of the pupil is
to control the amount of light entering the eye.
When you are in a bright environment, the pupil
becomes smaller to allow less light through. When
it is dark, the pupil expands to allow more light to
reach the back of the eye.
Iris:
This is the colored part you see in people’s eyes
(i.e. blue/green/brown/hazel). The primary
function of the iris is to control the size of the
pupil. This is achieved through contraction or
expansion of the muscles of the iris.
Ciliary Body:
Ciliary body lies in between iris and lens. It secrets
aqueous humour which helps in maintaining
intraocular pressure.
Choroid:
Choroid is a vascular membrane which supplies
90% of blood supply to eye.
Lens:
The lens is the clear structure located behind the
pupil. Its primary function is to provide fine-tuning
for focusing and reading. The lens performs this
function by altering its shape to become thinner or
thicker as necessary. Between the ages of 40 and
50, the lens becomes less flexible and presbyopia
sets in. As people reach their 60’s or 70’s, the lens
sometimes becomes cloudy and hard (cataract
formation), preventing light from entering the eye.
Vitreous Body:
This is the clear ‘gel like’ substance located inside
the eye’s cavity. Its purpose is to provide a
spherical shape to the eye. The vitreous may
develop small clumps known as ‘floaters,’ which
are more common in nearsighted people than in
the rest of the population.
Retina:
The retina consists of fine nerve tissue which lines
the inside wall of the eyes and acts like the film in
a camera. Its primary function is to transmit
images to the brain.
Optic Nerve:
The optic nerve carries images from the retina to
the brain.
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