2. 23-2
EYES AND EYE DISEASES
Eyes to See
All would agree that eyes are very important for us in our day-to-day living. The blind also adapt
themselves very well to understand the world around them. Yet, we know that if we had no eyes,
we would not be able to enjoy the trees, the birds and the butterflies in the beautiful different
colours that nature has made them in.
Light gets into our eyes
How do we see?
Our eyes take in the light that bounces off different things
around us. Once the information (light) reaches the inside of
the membranes of the eye, it creates small electric currents that
then travel through the nerves to the brain.
Different parts of the brain ‘read ‘ and make sense of the infor-
mation that has reached it as electric currents. This is how we
“see” things.
From eye, message is taken
to brain where it is “read”
Structure of the eye Parts of the eye
cornea Eyelids : The eyelids cover most part of the eye in
front and automatically close if a threat is faced from
(allows light in) front. The hair of the eyelashes can filter out dust
that can be damaging for the eye.
sclera
(protects)
Eye Balls: The eye is shaped like a ball. There is a
lens nerve behind this ball which takes information to
(to focus) the brain. The pair of eyes is located inside the hol-
low of the skull and gets protected by the skull bones
except from the front. A white membrane called the
sclera (skle-raa) covers the eyeball.
nerve
(to Cornea: The sclera ends in the front of the eye at the
cornea (kawr-niya) which is the transparent part of
brain)
the eye. It allows light to travel inside the eye.
pupil
(hole between iris) If the cornea is damaged leading to blindness, an eye sur-
eyelid geon can replace it by a cornea taken from a dead person
with eyelashes within a few hours of death. You can pledge your eyes to
the eyebank after your death and help the blind to see.
(protects eyes)
tear ducts
Tears Glands : Tear glands lie
Conjucntiva : Outside both the above the eyeball. Tears help to
sclera and the cornea, lies the a provide nourishment to the cor-
tear tube nea and the outer layers of the eye.
transparent (can see through) mem-
to nose
brane called conjunctiva (kun-junc- Why do we blink?
tie-va). This conjunctive gets red at Open eyes keep getting dry and blinking helps
times – like when we do not get to spread the tears to all parts of the outer eye
enough sleep or in times of infec- and is important for the health of the eye. Sleep-
tions called conjunctivitis(kun- ing helps the eyes keep healthy. Tears drain from
junc-ti-vye-tis). It protects the eye- the eyes into the nose – that is why we sniffle
ball from dust and germs. when we weep or when we cut
3. 23-3
Iris : Just behind the transparent cornea, lies the iris (eye-ris). This is like a round curtain with a hole in the
centre. Small smooth muscles in the curtain automatically increases or decreases the size of the hole de-
pending on how strong the light is. If there is less light, the hole – called pupil (pyoo-pil) becomes larger to
allow the little light reach the eyeball. If the light is very bright, the pupil automatically becomes smaller.
Take a torch and shine it in the eye of your neighbour. You will see the hole becoming smaller.
Lens in the eyes and its work
Lens : Inside the eyes just behind the pupil hole in the iris Vitamin A is needed
is the lens. It helps to focus the light information coming These rod and cones have
through the pupil onto a very special place on the retina proteins along with Vita-
(re-tye-nah or re-ti-nah). min A inside them. They
fail to work properly
The retina is the innermost layer of the eye, special like film when we have less Vita-
of a camera. It has special cells called rods and cones that min A. This is why chil-
convert the light information to weak electric signals. While dren who do not eat
rods are good at working even in weak, black and white enough green leafy veg-
signals, the cones are good at sending out different signals etables, pumpkin, car-
for each small variation in colours. While rods are found all rots, other yellow/red
around the retina, most cones are clumped together at one fruits and vegetables get
point and this is where the lens tries to focus all the light. Vitamin A deficiency and
are unable to see well
If the eyeballs are flat , the image by the lens may fall be- once it is dark. This is
hind the retina. On the other hand, if the eyeball is oblong, called night blindness.
the image falls in front of the retina. Glasses or “contact Vitamin A deficiency
lens” help in focussing the lens to fall at the corect place on may also dry up the cor-
the retina. Such patients should see a eye technician to get nea so that light cannot
correct glasses. pass through it properly.
Muscles of the eye
Muscles attached to the eyeball on the outside help to turn it up, down, sideways or in a combina-
tion of these. If the light is not enough to see properly, or if the lens cannot throw the image of
things on to the retina properly – if the eyeballs are too long or too flat - the eye muscles may have
to strain to help see properly. Constantly straining the muscles may lead to headaches. Diffuse
and enough light helps to avoid headaches. Glasses for those with a long or flat eyeball may also
help.
Eyes can warn of danger to body
1. If you shine a light into one eye of a person, the size of the pupil in both the eyes of a normal
person will decrease. However, if one of the eyes is heavily infected, the curtain-like iris will
fail to move with light and will show no response.
2. If the brain or the nerve to the eye has been injured in a head injury, the automatic response
to the light does not take place. Bleeding inside the brain may lead to a very small pupil
usually. A large big pupil only in one eye that does not move with light means that the eye has
been damaged to blindness by an injury, or that there is too much pressure inside the skull that
can damage the brain and lead to death. RUSH TO A DOCTOR.
3. Very small pupils seen on either side, or large big pupils on both sides can be due to different
drugs or medicines that the person has taken. Ask about it. Large pupils that do not move when
light is shone in the eyes can mean severe brain damage. One of ways to certify a person dead –
along with an absence of heartbeat and of breathing – is to check for ‘fixed wide pupils.’
5. 23-5
DISEASES OF
THE EYE
The eyes being so important to us, we must know how to deal with
common problems. Some of the common problems that we may face as
health workers are:
Page Number
1. Boils/stye of the eyelids. 23-6
2. Squint 23-6
3. Difficulty in seeing clearly 23-6
4. Red Painful Eyes
a) Foreign body in eye 23-7
b) Harmful splash in eye 23-7
c) Conjunctivitis 23-7
d) Trachoma 23-7
e) Iritis 23-8
f) Wound on cornea 23-8
g) Glaucoma 23-8
5. Cataract 23-8
6. Injuries to the eye 23-9
7. Night blindness/dry cornea 23-9
8. Double vision 23-9
6. 23-6
DISEASES OF THE EYE
1. Stye /Boils on eyelid
A red swollen boil on the eyelid, usually near the edge is called a stye.
Treating Styes
Apply a warm, moist cloth repeatedly with a little salt in the water. Splash
clean the eyes with clean water. Give CIPROFLOXACIN/ GENTAMICIN styes cause
eye drops 3- 4 times a day. Stop at least three days after the swelling has swelling in eyelid
decreased to prevent them from reappearing.
2. Squint(cross eyes)
If the movement of one eye does not match the other, we call it a squint. It may not only prevent
the person from seeing properly, a person with a squint receives many taunts and loses confi-
dence.
What to do in a squint?
If a child below six months of age is
seen to have a squint, keep the good
eye covered with a patch so that the
other eye gets a chance to look straight.
This may take not more than one or
two weeks.
If children below six years have a weak
eyesight, they tend to develop a squint
in order to see properly. Insist on a child
wearing glasses if a doctor has pre-
scribed them. A child’s eyesight should be checked for each eye separately before she enters school
and then every two years or so. Often children are reported to be dull and unintelligent when the
problem is actually with their eyesight !
3. Difficulty in seeing clearly
Eyes of children should be examined if they have trouble seeing
clearly or get headache and eye pain when they read or engage
in close-distance work that involves eye-strain like weaving car-
pets, doing embroidery.
Glasses of different types can be prescribed for children who
have trouble seeing clearly from afar. Exercises learnt from eye-
specialists that involve the eye muscles may also help in im-
proving eyesight. These days, some operations are also possi-
ble for those wish to avoid glasses.
Older persons beyond 40 years find it difficult to read or see
things clearly at close distance. They may be given reading
glasses and if this does not help, they should see an eye doctor.
7. 23-7
4. Red Painful Eyes
Removing a bit of dirt from the eye
a) Foreign body in eye
Usually a small speck of dirt or dust may
get into the eye and trouble the person.
The common place where it lodges is the
small groove in the edge of the upper eye-
lid. To remove it, upturn the upper eye-
lid and wipe the edge with a clean soft
cloth.Splashing clean water also helps.
Turn the eyelid with the help of small stick and
then clean the dirt out with a moist cloth
If the sensation of foreign body still persists, put some CIPROFLOXACIN /
GENTAMICIN drops, cover with a clean bandage and send to a doctor.
b) Harmful splash in eye
Petrol, diesel, battery acid, etc. may get into the eye and
cause severe pain and redness. Immediately splash clean
cool water and continue for about 30 minutes or until it
stops hurting. If the problem continues, show a doctor.
c) Conjunctivitis
Conjunctivitis
This happens when an infection leads to redness, pus and mild ‘burn-
ing’ in one or both eyes. There is severe watering of the eyes and the
lids stick together after sleeping.
Clean the pus with a clean cloth dipped in previously boiled
water. Eye drops of CIPROFLOXACIN/GENTAMICIN 3-
4 times a day may be of help sometimes.
Prevent Conjunctivitis from Spreading
redness, pus,
To prevent it from spreading –which it does easily – do not let a child
burning, watering
with this disease to play or sleep with others. Do not use one person’s towel or
of eyes & eyes stick
kerchief for another. Washing hands after touching the eyes is a good practice. It
together.
may be good for such patient not to meet others until the watering of eyes has stopped.
d) Trachoma
Trachoma is very common in India. It is a slow form of conjunctivi-
tis and may affect the eyelids, eyelashes and cornea if not treated
early. It spreads by touch, flies and dust.
What happens in Trachoma?
Repeated itching of eyes, watering and redness indicates trachoma. After a month
pinkish lumps inside or two, many small, pinkish lumps may be seen inside the eyelids. A grayish layer
eyelids; later it leaves white may be seen at the edge of the cornea because of new blood tubes getting in. Scar-
scars inside eyelids ring of the eyelids may thicken the eyelids and pull the eyelashes that may rub
against the cornea to cause blindness.
To treat Trachoma, it is important to give DOXYCYCLINE /COTRIMOXAZOLE by
mouth for at least 10 days with CIPROFLOXACIN/GENTAMICIN eyedrops for about
three weeks.
8. 23-8
e) Iritis (Inflammation of Iris) Inflammation of Iris
It usually happens only in one eye. Pain, usually suddenly along
with redness around the iris of the eye is common. The eye waters a
lot and it is painful to see in bright light. There is no pus as in con-
junctivitis. Vision is not clear. There may be a small and irregularly
round pupil.
Rush for help. Antibiotics do not help.
pain, redness in iris,
eye waters, painful to
see light
f) Wound on cornea
Seen in good light, a scrape or wound on the cornea can be seen as a small gray spot
or scar. Put antibiotic eyedrops like CIPROFLOXACIN/GENTAMICIN four times a
day is important if there is pain. An old scar may not pain and should be operated
only if the person is blind.
g) Glaucoma (Glaw-kow-ma)
This can cause blindness and is due to a high pressure in the eyes usually after the age of forty.
There are two forms of Glaucoma:
Acute Glaucoma:
This starts with sudden headache or severe pain in the eyes. The eye
gets red and vision is blurred. The person may even vomit
due to pain. The pupil of the painful eye is big and the
eye feels hard to touch. The person may see ‘coloured rings normal glaucoma
around a bulb or light.’ If not treated by operation early
enough, it may turn the person blind. Rush to a doctor.
Chronic or slow Glaucoma:
There is no pain. The pressure in the eye rises slowly and the person loses vision from the sides
slowly. The person cannot see an object at the sides of his eyes as much in front as
normal people. Feeling the closed eye with fingertips gives a hard feeling.
Refer to a doctor. Continual drops in the eyes will be required to be given for life.
Operation may also be needed.
5. Cataract
The lens of the eye behind the cornea may turn white or cloudy Cataract
with old age. This does not allow light to pass through the lens to
the retina. The pupil may look gray or white when light is shone
into it. This is cataract and may cause blindness.
If the person can tell light from dark or make out any movement,
an operation that removes the lens may help in seeing with thick pupil looks gray or white
glasses. Such operations are performed free of cost by District Blind- and person cannot see
ness Societies in every district. These days, a cheap plastic lens can clearly
be inserted in the eye after removing the white lens to allow the
person to see without glasses.
9. 23-9
6. Injuries to the eye
Injuries to the eye may be caused by:
¨ Fireworks ¨ Sparks during welding
¨ Balls ¨ Blunt injuries with a fist
¨ Stones ¨ Petrol/chemical splashes
Treating Eye Injuries
All injuries to the eyes may be dangerous.
Any cuts on the cornea may get infected and cause blindness – put repeated
antibiotic eye drops like CIPROFLOXACIN/GENTAMICIN.
If a wound is deep, it is dangerous. If a blunt injury fills the eyeball with blood,
this is also dangerous as it may cause blindness.
If the suddenly the pain increases after a few days of the injury, rush to an eye
doctor.
Always check the eyesight in the injured eye while the good eye is covered. If there is no
problem is seeing, put antibiotic drops and cover with a thick, soft bandage. If no im-
provement, show a doctor.
If there is problem in seeing with the injured eye, or if there is blood behind the cornea,
cover the eye with a clean piece of cloth or bandage and rush to a doctor.
7. Night blindness/dry cornea
Usually this happens due to Vitamin A deficiency, although
rarely it may be present since birth. Occurring in those who do Vitamin A rich foods
not eat enough green leafy vegetables, pumpkins, yellow or red should be eaten
fruits and vegetables, whole milk, eggs, liver or kidneys, Vita-
min A deficiency is common between the age of 1 and five years.
Initially the child may complain of being unable to see well
after dark. Later she may get dry eyes, and bubbles may de-
velop in the white of the eyes. Later the cornea may get soft and
bulge. This often begins in children with a bout of severe diar-
rhoea, measles or prolonged cough.
Prevention : If a child is unlikely to get such food, give Vitamin A every six months. 2,00,000
(two lakh) units every six months for children above one year of age. Above six months and less
than one year age, give only 1,00,000 units every 6 months. Do not give to less than 6 months
old child.
Treatment: If night blindness or dry cornea is already seen, 2,00,00 units on two consecutive days
must be given followed by 2,00,000 units after two weeks. For children above six months but less
than one year, give 1,00,000 units instead for the three doses.
8. Double vision
Double vision that occurs only from time to time, it is a sign
of weakness or malnutrition. Improve the diet of the person
to get better.
Those who get double vision suddenly or it is present for
along time – even getting worse – is a serious sign. Show a
doctor.
10. 23-10
Know the Answers
The Eye & Eye Diseases
a. Please mark if “right” or “wrong”:
1. Cornea is the white part of the eye.
2. Redness of the eye can be due a disease of the conjunctiva, of the cornea and of the iris.
3. The lens can be replaced from a dead person’s eye.
4. The pupil becomes large when a light is shone in the eye.
5. Glasses can help focus an eye’s light correctly on the retina.
6. Squint should be treated only after the age of eight years.
7. For cataract, GENTAMICIN / CIPROFLOXACIN
8. Vitamin A necessary for the eyes is found in guavas and citrus fruit like lemons, oranges etc.
9. CIPROFLOXACIN, GENTAMICIN eye drops should be given four times daily for all infec-
tions of the eye.
10. Eyesight of the injured eye can be checked by covering the injured eye and asking the person
to look from the good eye.
b. Please fill in the blanks:
1. Difficulty in seeing that slowly leads to blindness is normally seen in people after forty years
of age in:
a. _________________________________
b. _________________________________
2. A painful red eye maybe found in:
a. _________________________________ b._________________________________
c. ________________________________ d. ________________________________
e. _________________________________ f. ________________________________
g. _________________________________
3. Trachoma can be diagnosed by the following signals :
a. ________________________________ b. ________________________________
c. ________________________________
4. The lens help to focus light on to the ___________________________ and can become white
in ________________________.
5. Vitamin A, good for the eyes can be found in foods like ______________, _____________
and _____________________.
