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Tamil Nadu State Blindness Control Society


What is a cataract? 
A cataract is a cloudy area in the lens of the eye. The lens helps focus light on the retina at the back of the eye. It is located behind the iris (the colored part of the eye). As a cataract grows larger over time, the cloudiness worsens and causes vision problems.

How does it occur? 
Most cataracts occur naturally as people get older. What causes cataracts is not known, but many factors may contribute to their formation, such as:

  • eye injury 

  • diabetes or other diseases 

  • exposure to radiation, especially x-rays 
  • long-term use of steroids
  • exposure to toxic substances 
  • prolonged exposure to sunlight. 

Cataracts don't spread from one eye to the other, but many people have cataracts in both eyes.

What are the symptoms? 
The symptoms of a cataract include: 

  • blurred vision 

  • a need for frequent changes in your eyeglasses or contacts 

  • trouble driving at night 
  • sensitivity to bright light 
  • change in color vision (yellow, orange, and red appear brighter and WHITE appears dull).

How is it diagnosed? 
The symptoms of a cataract develop slowly and are painless. The condition may go unnoticed and undiagnosed for a long time. It is often first diagnosed during a routine eye exam.

How is it treated? 
If a cataract is not interfering with your lifestyle or work, your doctor may suggest changing your glasses or using brighter lights to help you read.

If the cataract is seriously affecting your vision and cannot be helped with glasses or contact lenses, a surgeon may need to remove the lens. This type of surgery is called cataract extraction surgery. After the lens is removed your surgeon may put a new plastic lens in your eye (intraocular lens implantation). If you do not have a new lens put in, you will need to wear contact lenses or cataract glasses.

How long will the effects last? 
Decreased vision from cataracts is reversible and will last until it is corrected with glasses, contact lenses, or surgery. Surgery to remove cataracts is highly successful in restoring vision.

What can be done to help prevent cataracts? 
You may reduce the risk of damaging your eyes and in turn reduce the risk of developing cataracts by wearing goggles or safety glasses at work or during recreation where your eyes could be injured. Wearing glasses with a UV coating that protects your eyes from sunlight might prevent or delay some types of cataracts, but this is not proven.

If you are a woman and plan to have a baby, make sure you have had a German measles (rubella) shot at least 3 months before you become pregnant. If you have German measles while you are pregnant, your baby's eyes should be checked by an eye care professional soon after birth. A baby can develop cataracts if you had German measles while you were pregnant.

Viral or Bacterial Conjunctivitis 

What is conjunctivitis? 
Conjunctivitis is inflammation of the conjunctiva. The conjunctiva is the clear membrane that lines the eyelids and covers the white of the eye.

How does it occur? 
Conjunctivitis can be caused by many things, including infection by viruses or bacteria. Viruses that cause colds may lead to conjunctivitis. Some bacteria that cause conjunctivitis are chlamydia, staphylococci, and streptococci. Severe conjunctivitis, such as that caused by gonococci, can cause blindness.

  • Viral forms of conjunctivitis can be spread easily from person to person. They can be spread by coughing or sneezing. Bacteria or viruses can get in your eyes through contact with contaminated objects.

What are the symptoms? 
Symptoms may include: 

  • itchy or scratchy eyes 

  • Redness 

  • Sensitivity to light 
  • Swelling of eyelids 
  • Watery discharge 
  • Discharge of pus. 

How is it diagnosed? 
Your doctor will ask about your medical history and if you have been near someone who has conjunctivitis. He will examine your eyes. He or she will also check for enlarged lymph nodes near your ear and jaw. If the conjunctivitis appears to be caused by bacteria, he may get lab tests of a sample of the pus to see what type of bacteria are present.

How is it treated? 
Like a cold, viral conjunctivitis will usually go away on its own, even without treatment. However, your doctor may prescribe eyedrops to help control your symptoms. Antihistamine pills may also relieve the itching and redness.

If you have bacterial conjunctivitis, your health care provider will prescribe antibiotic eye drops. You can also help your eyes get better by washing them gently to remove any pus or crusts. Then dry them gently with a clean towel.

If you wear contact lenses, you will need to stop wearing them until your eyes are healed. The combination of contacts and conjunctivitis may damage your cornea (the clear outer layer on the front of your eye) and cause severe vision problems.

How long will the effects last? 
Viral conjunctivitis usually gets worse 5 to 7 days after the first symptoms. It can improve in 10 days to 1 month. If only one eye is affected at first, it may take up to 2 weeks for the other eye to be affected. Usually, if both eyes are affected, the first eye has worse conjunctivitis than the second.

Bacterial conjunctivitis should improve within 2 days after you begin using antibiotics. If your eyes are not better after 3 days of antibiotics, call your health care provider.

How can I prevent conjunctivitis? 
To keep from getting conjunctivitis from someone who has it, or to keep from spreading it to others, follow these guidelines:

  • Wash your hands frequently. Do not touch or rub your eyes. 

  • Never share eye makeup or cosmetics with anyone. Also, if lab results show that you have conjunctivitis, throw out eye makeup you have been using.

  • Never use eye medicine that has been prescribed for someone else. 
  • Do not share towels, washcloths, or sheets with anyone. If one of your eyes is affected but not the other, use a separate towel for each eye.
  • Avoid swimming in swimming pools if you have conjunctivitis. 

When should I consult a doctor? 
Consult if: 

  • You have any severe eye pain. 

  • Your symptoms do not improve after you have used your medicine for 3 days. 

  • Your eyes become very sensitive to light, even up to a few weeks after the redness is gone.

Diabetic Retinopathy 

What is diabetic retinopathy? 
Diabetic retinopathy is an eye problem caused by diabetes mellitus. It affects the retina, which is light-sensitive tissue at the back of the eye. Retinopathy occurs when diabetes damages the tiny blood vessels in the retina. This damage can lead to problems with your vision, including blindness. However, you may be able to prevent severe vision problems if:

  • You keep your diabetes under control. 

  • You have regular eye exams. 

  • You get early treatment for retinopathy. 

How does it occur? 
High blood sugar levels damage small blood vessels. The weakened blood vessels may break and leak fluid and blood. Also, new abnormal blood vessels may grow. These new blood vessels can bleed, cause cloudy vision, and destroy the retina.

The longer you have had diabetes, the more likely you are to have retinopathy. 

What are the symptoms? 
Diabetic retinopathy begins before you have any symptoms. As the problem gets worse, you may have:

  • Blurred vision 

  • Floaters, which are black spots or cobweb like shapes 

  • Temporary or permanent blindness. 

How is it diagnosed? 
The doctor will look at your eyes with a special light. He or she will be able to see inside your eyes and look for signs of retinopathy. Your doctor may refer you to an eye specialist (an ophthalmologist or optometrist).

How is it treated? 
Early treatment before the retina has been badly damaged is the most successful in reducing vision loss from this disease.

Your eye surgeon may use a laser to seal leaking blood vessels. The surgeon may also use a laser to destroy abnormal blood vessels.

If you have had bleeding into the clear gel (vitreous) that fills the inside of the eye, the eye surgeon may remove the gel. The gel will be replaced with a clear fluid. This procedure is called a vitrectomy.

How long will the effects last? 
As long as you have diabetes, there is a chance you will have retinopathy. However, careful control of your blood sugar levels will help delay and possibly prevent vision loss.

You may need to be treated more than once for retinopathy. Have your eyes checked regularly to make sure you get treatment when you need it.

Retinopathy can cause the retina to become detached. This means the retina is pulled away from the back of the eye. If this happens, you need to see your doctor for urgent treatment to reduce the chance of permanent vision loss. Consult your doctor right away if you start seeing dark spots, floaters, or light flashes or your vision is blocked, blurred, or distorted.

How can I take care of myself? 
Follow your doctor's recommendations and these guidelines: 

  • Make sure you have eye exams regularly. Ask your doctor how often your eyes should be checked.

  • Immediately tell your doctor if you have any change in your vision. 

What can be done to help prevent diabetic retinopathy? 
To help prevent diabetic retinopathy, follow these guidelines: 

  • Control your blood sugar. 

  • Control your blood pressure. 

  • Stop smoking. (Smoking may speed up the development of retinopathy.) 

Follow your diet and health care plan for your diabetes so you have fewer complications. 

Eye Medicines: Eyedrops and Ointments 
If you need to use eyedrops or ointments in your eyes, you will get the most benefit from your medicine if you use it properly.

Some general guidelines are: 

  • Always use the amount of medicine your health care provider has prescribed. Do not use it more often than prescribed.

  • Do not use this medicine for other eye conditions unless your health care provider approves.

  • Never share eye medicines with others. 
  • Before you start, wash your hands thoroughly. 
  • Read the label on the medicine to make sure you have the right one. 

If you develop any new redness or irritation while you are using your medicine, contact your health care provider.

How are eyedrops used? 

  • Shake the bottle thoroughly. 

  • Tilt your head back and pull your lower eyelid down to form a pouch. 

  • Hold the bottle directly above your eye. Look up, and squeeze a drop of the medicine into the pouch. To avoid contaminating the medicine, do not let the tip of the bottle touch your eye or any other surface.
  • Close your eye for a minute or two, and with a fingertip press gently on the inside corner of your eye to keep the medicine from draining out. Do not rub your eye.
  • Put the cap on tightly, and store the medicine away from heat and bright light. Do not use eyedrops that are old or discolored.

If you have trouble using eyedrops, ask someone to help. 

How are eye ointments used? 

  • Hold the tube of ointment in your hand for a few moments. This will warm the medicine so it will flow easily from the tube. Do not use ointment that has dried out.

  • Tilt your head back, and pull your lower eyelid down to form a pouch. 

  • Look up, and squeeze a 1/4-inch-long ribbon of ointment into the pouch. To avoid contaminating the medicine, do not let the tip of the tube touch your eye or any other surface.
  • Blink a few times to help spread the ointment over your eye. Do not rub your eye. 
  • Put the cap on tightly, and store the medicine away from heat and bright light. 

Your vision may be blurry for some time after using your ointment. Avoid driving and other activities that require good vision until you can see clearly.

Can I wear contact lenses while I am using eye medicines? 
Do not wear your contacts when you are putting eye medicines in your eyes. Sometimes you can put your contacts in about 10 minutes after you have used your medicine. However, some eye medicines will stain your contacts. Ask your health care provider about wearing contacts while you are using your eye medicine.

If you have any questions about using your eye medicines properly, ask your health care provider.

Chemical in Eye 


Acids and alkalis splashed into the eye can severely damage the cornea (clear part of the eye). However, most chemicals just cause temporary stinging and superficial irritation (for example, alcohol or hydrocarbons). All should be treated as emergencies and preferably by an eye doctor.


Immediate and thorough irrigation of the eye with tap water is essential to prevent damage to the cornea. (Do not use antidotes such as vinegar.) This irrigation should be performed at home and as quickly as possible. Either hold your child's face up under a gently running water tap or have your child lie down and continuously pour lukewarm water into the eye from a glass. It is very important to hold the eyelids open during this process. For most chemicals, the eye should be irrigated for 5 minutes. However, it should be irrigated for 10 minutes for acids and 20 minutes for alkalis. Immediately consult an eye doctor for further advise.

Eye Trauma 


This guideline covers injuries to the eye, eyelid, and area around the eye. The main concern is possible damage to your child's vision. Older children can tell us if their vision is blurred or out of focus. Test your child's vision at home by covering each eye in turn and having your child look at a distant object. Children less than 3 years old usually need to be examined by a physician to answer this question.


Superficial cuts or scrapes 
First wash your hands. Protect the eye with a clean cloth, then wash the wound vigorously with liquid soap and water for 5 minutes. Rinse the wound well. Then apply pressure for 10 minutes with a sterile gauze to stop bleeding. Leave the area exposed to the air. Antiseptic ointments are usually unnecessary.

Swelling or bruises with intact skin 
Swelling usually follows injury to the soft tissues or bone around the eye. Apply ice for 20 minutes. A subconjunctival hemorrhage (bruise of the white of the eyeball) also shouldn't cause undue concern. These unsightly bruises are harmless. They do not spread to inside the eye and clear up in about 2 weeks.

Prevention of eye trauma 
o Objects that penetrate the eyeball often result in loss of vision. Don't buy your child an air-powered gun (BB gun).


  • There is any injury to the eye itself. 

  • The skin is split open and may need stitches. 

  • Vision is blurred in either eye. 

Foreign Body in Eye 


An eyelash, sawdust, sand, or dirt can get into the eyes. The main symptom is irritation or pain.


With your child bending forward, try to get flakes of glass off the skin by blowing on the closed eyelids. Pour water over the eyelids and face to get off any remaining glass. Cover the eyes with a wet washcloth and consult an eye doctor. The eye should not be rubbed.


  • Treatment for numerous particles 

If there are numerous particles in the eye (such as dirt or sand), clean around the eye with a wet washcloth first. Then have your child try to open and close the eye repeatedly while submerging that side of the face in a pan of water. If your child is too young to cooperate with this, hold him face up under a gently running warm water tap. The eyelids must be held open during the irrigation.

  • Treatment for particle in a corner of the eye 

 If the particle is in the corner of the eye, try to get it out with the corner of a clean handkerchief or a moistened cotton swab.

  • Treatment for particle under the lower lid 

If the particle is under the lower eyelid, pull the lower lid out by depressing the cheek and touch the particle with a moistened cotton swab. If that doesn't work, try pouring water on the speck while holding the lid out.

  • Treatment for particle under the upper lid 

If the particle can't be seen, it's probably under the upper lid (the most common hiding place). Try having your child open and close the eye several times while his face is submerged in a cake pan or pie pan of water. If this fails, pull the upper lid out and draw it over the lower lid. This will sometimes dislodge the particle.


  • The object hit the eye at high speed (as from striking metal on metal or metal on stone).

  • The foreign object is sharp. 

  • Irrigation does not remove all the foreign material from the eye (that is, you can see it or the sensation of "grittiness" or pain persists).

    (While your child is waiting to be seen by the physician, cover his eye with a wet washcloth or bandage it shut to relieve discomfort.)

  • Your child's vision does not return to normal after the eye has been irrigated. 

  • The foreign object has been removed, but tearing and blinking persist. 


What is glaucoma? 
Glaucoma is an eye disease in which the optic nerve is damaged. Usually, high pressure inside the eye causes the damage. The damage can lead to a loss of vision. However, early treatment can prevent blindness.

How does it occur? 
A clear, watery fluid called the aqueous humor normally circulates in your eye. When the flow of this fluid out of the eye becomes blocked, the pressure increases inside the eye. The increased pressure can damage the optic nerve.

There are two main types of glaucoma, depending on how the flow of fluid is blocked: 

  • Open-angle glaucoma is caused by a gradual blockage in the area that drains fluid from the eyes into the drainage channels. It usually affects both eyes.

  • Closed-angle glaucoma is a blockage caused by a change in the position of the iris (the colored part of the eye). The change in position causes the iris to block the drainage channels. This type of glaucoma usually happens in one eye at a time. If you get glaucoma in one eye, you are at risk for having the same problem in the other eye. When this type of glaucoma happens suddenly, it is called acute closed-angle glaucoma and is a medical emergency.

  • Glaucoma tends to run in families. It occurs most often after age 40, but sometimes children have it.

What are the symptoms? 
Open-angle and other chronic forms of glaucoma often have no symptoms in the early stages. In later stages, you will begin to notice a loss of vision. Side vision is affected first.

Symptoms of acute closed-angle glaucoma include: 

  • Severe eye pain 

  • Seeing halos around lights 

  • Nausea and vomiting 
  • Headache 
  • Loss of vision. 

How is it diagnosed? 
Your health care provider may screen you for vision problems during your routine checkups. If you have vision problems, your provider will refer you to an eye doctor.

The eye doctor may use the following tests to diagnose glaucoma: 

  • Tonometry, a painless procedure used to measure the pressure in your eyes 

  • Ophthalmoscopy, in which the doctor uses an instrument to look at the optic nerve inside your eye

  • Visual field testing, which can show early changes in your side vision caused by damage to the optic nerve
  • Gonioscopy, which is a method of examining the drainage channels. 

How is it treated? 
The goal in the treatment of glaucoma is to reduce the pressure in your eyes. This may be done with eye drops, oral medication, laser surgery, or other types of surgery. Some eye drops reduce the amount of fluid made by your eye. Others increase the amount of fluid that flows out. Surgery relieves pressure inside the eye by opening up the drainage channel or by making another opening through which the fluid can drain.

How long will the effects last? 
Loss of vision caused by glaucoma is permanent. This is why glaucoma needs to be diagnosed and treated early to stop further damage to the optic nerve.

If your eye doctor prescribes medication to control the pressure, you may need to take it for the rest of your life.

How can I take care of myself? 

  • Take your medication as prescribed. 

  • Carefully follow your doctor's advice for follow-up visits and pressure measurements.

 How can I help prevent glaucoma? 
Glaucoma cannot be prevented. However, blindness can be prevented if glaucoma is treated before pressure in the eye has damaged the optic nerve too much.

You may be able to help prevent glaucoma from becoming severe if you: 

  • Have a regular eye exam. How often you need to see the eye doctor will depend on how severely your optic nerve was damaged.

  • At your eye exam, make sure the pressure in your eye is measured and that your optic nerve is examined.

  • Learn about your family history. Chronic open-angle glaucoma often runs in families. 
  • See your health care provider at once if you see halos around lights or notice any changes in your vision.

Headaches and Eye Problems 

Do eye problems cause headaches? 
Headaches are a very common health problem. They can have many different causes. Sometimes, but not usually, eye problems are a cause.

What causes headaches? 
Tension, anxiety, strain, stress, fatigue, and depression may all bring about sudden or gradual muscle contraction and pain.

Migraine headaches are another common type of headache. Migraines are usually much more severe than muscle contraction headaches. They are caused by changes in the blood vessels and blood flow in the head.

Headaches can also be caused by many diseases and disorders affecting other parts of the body. For example, ear problems, jaw problems, sinus problems, arthritis, high blood pressure, nerve diseases, and even tumors can cause headaches.

Rarely, eye problems cause headaches. For example, if you need reading glasses and read for a long time without glasses, or with glasses that are too weak, you may develop eye strain and a headache. Also, you may have a headache from reading or doing close work if your eyes are misaligned. That is, certain eye muscles may be too weak to focus up close. This weakness is one of the few eye problems that can often be successfully treated with eye muscle exercises.

How are headaches treated? 
Treatment for headaches varies, depending on the cause. Proper diagnosis is important, so tell your health care provider if you have severe, frequent, or ongoing headaches. He or she will try to determine the cause and proper treatment.

If it appears that your headaches are caused by eye problems, you may be referred to an eye doctor. A new glasses prescription may be the treatment you need. If your eyes are misaligned, eye muscle exercises are often helpful.

How can I help prevent headaches caused by eye problems? 
Make sure you have regular checkups with your eye doctor


What is presbyopia? 
Presbyopia is the loss of clear close-up vision that occurs naturally as people get older. 

How does it occur? 
Around the age of 40, the lenses of your eyes begin to lose elasticity and flexibility. You may find that you are unable to focus sharply on close objects. You may need to hold things farther away from your eyes to see them clearly.

What are the symptoms? 
Presbyopia develops gradually. At first you may have blurred vision when you read or do close-up tasks such as threading a needle. Later you may not be able to read normal newsprint or book print without reading glasses or a magnifying glass and good lighting.

How is it diagnosed? 
Presbyopia does not require diagnosis if you have no other symptoms. Your eye doctor can verify your condition during a regular visit or glaucoma check.

How is it treated? 
There is no treatment that can make your lenses flexible again. However, reading glasses, bifocals, trifocals, progressive lenses (no lines), and possibly contact lenses can help you see close-up objects. Discuss these options with your eye doctor.

How long will the effects last? 
Presbyopia is a permanent change that tends to worsen very gradually over time.