STUDY OF EYE DISEASES
Project Report in
BIOLOGY
2020-2021
Submitted in partial fulfillment
Of the requirement of Class XII (C.B.S.E)
[Reg No: ]
Under the guidance of
Mrs. G.PRIYA
(PGT BIOLOGY)
Mahatma Montessori School (C.B.S.E)
Madurai
CERTIFICATE
This is to certify that the project entitled “Study of Eye
diseases” is done by J
of Class XII of Mahatma Montessori School (C.B.S.E), Madurai
has completed the project as a part of the paper of Biology
under my supervision. He has taken proper care and showed at
most sincerity in the completion of this project.
I certify that this project is up to my expectation as per the
guidelines issued by C.B.S.E.
PRINCIPAL
Submitted for the viva-voce conducted on, at Mahatma
Montessori School (C.B.S.E), Madurai.
INTERNAL EXAMINER EXTERNAL EXAMINER
ACKNOWLEDGEMENT
In the accomplishment of this project successfully, I utilize
this opportunity to thank all the people who have bestowed
upon me their blessings and their heart pledged support.
Primarily I would thank God for helping me to complete
the project with success. Next I would like to thank my Principal
Mrs. Subha for her valuable guidance throughout the project.
Then I would like to thank my Biology Teacher Mrs. Priya
(PGT Biology), whose valuable guidance and co-operation
throughout the project have helped me to patch this project
and make it full proof success. Her suggestions and instructions
in all the stages of my work have served as the major
contribution towards the completion of this project.
Then I would like to thank my who has helped me with
useful suggestions in various phases of the project and
complete it with great success.
CONTENT
● INTRODUCTION
● EYE – THE Human Camera
● Structure of eye
● 1.External structure
● 2. Internal structure
● Eye diseases and treatment
⮚ Myopia
⮚ Hypermetropia
⮚ Presbyopia
⮚ Cataract
● BIBLIOGRAPHY
INTRODUCTION:
Introduction to the eye
The eye is a spherical organ located inside the skull
(within a bone structure called the “orbit”), which
connects to our brain through the optic nerve
(ON).
We are born with two eyes that allow us to see
the world where we live, by decoding a sensorial
input (information that enters the eye in form of
light) and by “translating” it into electrical
information that can travel through the ON to the
neurons of our brain.
The brain then processes and integrates this data,
using it for different purposes, such as helping us
see where we are walking, recognize someone’s
face, see colours, etc…
Structure of the Eye:
The human eyes are the most complicated sense organs in the
human body. From the muscles and tissues to nerves and blood
vessels, every part of the human eye is responsible for a
certain action. Furthermore, contrary to popular belief, the
eye is not perfectly spherical; instead, it is two separate
segments fused together. It is made up of several muscles
and tissues that come together to form a roughly spherical
structure. From an anatomical perspective, the humaneye can
be broadly classified into the external structure and internal
structure.
The External Structure of an Eye
The parts of the eye that are visible externally include
the following:-
Sclera: It is a white visible portion. It is made up of
dense connective tissue and protects the inner parts.
Conjunctiva: It lines the sclera and is made up of
stratified squamous epithelium. It keeps our eyes moist
and clear and provides lubrication by secreting mucus
and tears.
Cornea: It is the transparent, anterior or front part of
our eye, which covers the pupil and the iris. The main
function is to refract the light along with the lens.
Iris: It is the pigmented, coloured portion of the eye,
visible externally. The main function of the iris is to
control the diameter of the pupil according to the light
source.
Pupil: It is the small aperture located in the centre of
the Iris. It allows light to enter and focus on the
retina.
The Internal Structure of an Eye:
The internal components of an eye are:
Lens: It is a transparent, biconvex, lens of an eye. The lens is
attached to the ciliary body by ligaments. The lens along with
cornea refracts light so that it focuses on the retina.
Retina: It is the innermost layer of the eye. It is light
sensitive and acts as a film of a camera. Three layers of
neural cells are present in them, they are ganglion, bipolar and
photoreceptor cells. It converts the image into electrical
nerve impulses for the visual perception by the brain.
Optic nerve: It is located at the posterior portion of the
eyes. The optic nerves carry all the nerve impulses from the
retina to the human brain for perception.
Aqueous Humour: It is a watery fluid present between the
cornea and the lens. It nourishes the eye and keeps it
inflated.
Vitreous Humour: it is a transparent, jelly-like substance
present between the lens and the retina. It contains water
(99%), collage, proteins, etc. The main function of vitreous
humour is to protect eyes and maintain its spherical shape.
EYE DISEASES:
1.MYOPIA(NEAR SIGHTEDNESS)
Is it hard to see distant objects, like highway signs,
until you’re a few feet away, but easy to read a book up
close? Chances are you’re myopic, also known
as nearsighted. It’s a pretty common condition that
your eye doctor usually can fix with eyeglasses,
contacts, or eye surgery.
What Causes Myopia?
The cornea is the clear, dome-shaped front
surface of your eye.
The lens is a clear structure about the size and
shape of an M&M's candy.
In a normally shaped eye, each of these focusing
elements has a perfectly smooth curvature, like the
surface of a marble. A cornea and lens with such
curvature bend (refract) all incoming light to make a
sharply focused image directly on the retina, at the
back of your eye.
Symptoms
Chances are the only symptom is that more distant
objects are blurred. You may also notice:
Headaches
Squinting
Eye strain
Eye fatigue when you try to see objects more than
a few feet away
Children with myopia often have trouble reading
the blackboard at school.
Diagnosis and Treatment
An eye exam can show you if you’re myopic. Glasses,
contacts, or refractive surgery can usually correct the
problem.
When you have myopia, your prescription for glasses
or contact lenses will be a negative number. The more
negative the number, the stronger your lenses will be.
For example, -3.00 is stronger than -2.50.
2.Hypermetropia(Far sightedness)
Hypermetropia (long-sightedness) is a common eye
condition where nearby objects appear blurred, but
your vision is clearer when looking at things further
away.
If you feel your eyes are often tired and you have
problems focusing on objects close to your eyes, you
may have hypermetropia
Causes:
One cause may be that your eyeballs are shorter
than usual. This means that the retina is closer to
the pupil, causing light to travel past the retina. A
normal eye is usually around 23mm in length, so an
eye that is hypermetropic will be shorter than
23mm.
Alternatively you can also have hypermetropia if
your cornea is flat. The cornea should be curved to
direct light onto the retina.
Both of these factors cause long-sightedness, as they
cause light to travel past the retina. This results in
blurry vision, and can affect your daily life.
Corrections:
Hypermetropia is corrected using a convex lens of
appropriate power. The convex lens converges the
light rays so that the final image from human eye lens
is formed on the retina.
3.PRESBYOPIA:
Presbyopia is caused by changes in the lens inside the
eye. As people age, the lens becomes harder and less
elastic, making it more difficult for the eye to focus on
close objects. Presbyopia is a vision defect that
happens due to the weakening of the ciliary muscles of
the eye lens. Presbyopia is typically present in
individuals aged 40 years and above. Some of the
common visual symptoms are:
Having difficulty reading small print
Requiring brighter light when reading
Having eye strain or headache when reading
or doing work close up
Difficulty focusing on objects that are nearer
Corrections:
Presbyopia can be managed with glasses, contact
lenses, or surgery. This defect is usually corrected by
using glasses with bifocal power of suitable focal
lengths. The upper part of the lens is a concave lens
corrects myopia to see the distant objects clearly
while the lower part of the lens has a convex lens
corrects the hypermetropia to see the nearby objects
clearly.
CATARACT:
A cataract is a dense, cloudy area that forms in the
lens of the eye. A cataract begins when proteins in the
eye form clumps that prevent the lens from sending
clear images to the retina. The retina works by
converting the light that comes through the lens into
signals. It sends the signals to the optic nerve, which
carries them to the brain.
It develops slowly and eventually interferes with your
vision. You might end up with cataracts in both eyes,
but they usually don’t form at the same time. Cataracts
are common in older people.
Treatment of Cataract:
Surgery
Surgery is recommended when cataracts prevent you
from going about your daily activities, such as reading
or driving. It’s also performed when cataracts
interfere with the treatment of other eye problems.
One surgical method, known as phacoemulsification,
involves the use of ultrasound waves to break the lens
apart and remove the pieces.
Extracapsular surgery involves removing the cloudy
part of the lens through a long incision in the cornea.
After surgery, an artificial intraocular lens is placed
where the natural lens was.
Surgery to remove a cataract is generally very safe
and has a high success rate. Most people can go home
the same day as their surgery.
BIBLIOGRAPHY:
1. myeye.gov
2. myeyemywealth.org
3. www.wikipedia.com
4. www.basicallybiology.com
5. www.1000sciencefairprojects.com
6. www.sciencedirect.com
