What is Cataract:

Cataract is a condition of the eye wherein the eye lens turns opaque. The opacity may be complete or partial depending on the age or maturity of the cataract. Normally the eye lens is clear and transparent and serves the function of directing the rays of light from an object  to converge exactly on the retina of the eye, which is  situated on the posterior wall of the eye ball.

When the eye lens develops cataract, the rays of light from an object entering the eye lens are not properly refracted and do not converge to meet on the retina  due to the opacity developed in the cataract lens. The object is therefore not viewed clearly or not viewed at all depending on the maturity of the cataract.

Image showing refraction of light through  normal and cataract lens and vision changes in cataract.

Causes of Cataract Eye and Types of Cataract.

1. Advancing Age Cataract is the most common type of Cataract.
2. Secondary Cataract which develops
   • Due to an Eye Surgery after Glaucoma.
   • Due to  Diabetes.
   • Due to prolonged use of  medications like steroids, major tranquilizers and diuretics  also fall in this category.
   • Due to excessive exposure to ultra violet rays which are present in sunlight. Use of sun glasses or a broad rimmed hat helps to prevent cataract.
   • Due to heavy consumption of Alcohol.
   • Due to excessive Smoking.
3. Cataracts due to trauma to the eye can occur even after a few years.
4. Radiation Cataract occurs due to exposure to cosmic radiation. For this same reason, pilots and astronauts are at greater risk to develop cataract.
5. Congenital cataract is seen in newborns babies. It develops due to hereditary enzyme defects. Vision may or may not be affected. Surgery is advised if vision is impaired.
6. Iodine Deficiency can also cause Cataract.

Why Cataract Develops.

The lens of the eye is made of water and specific proteins, which give the lens its transparency and clarity.  With advancing age and due to causes mentioned above, the structure of these specific proteins of the eye lens change, and the lens loses its transparency, leading to gradual clouding of the lens. This , in short, is the patho physiology of cataract.

Symptoms of Cataract:

• Blurring of vision. It can be compared to vision through  dirty and soiled glass.
• Night vision is impaired.
• Colors seem to lose their brightness.
• There is frequent need to change prescription of eye glasses.
• Sunlight, incoming car headlights, etc appear too bright.
• Please note that Cataract does not cause any pain or swelling of the eyes. Any such symptoms are due to some other eye pathology and should be referred to an ophthalmologist.

How Cataract can be Prevented.

Study the causes of Cataract and you will know how to prevent cataract.

• Use sunglasses and a broad rimmed hat when you are out in the sun.
• If you are Diabetic, keep your blood sugar under control.
• Do not use medicines without advice from your physician. They could be predisposing to cataract formation.
• Avoid alcohol and smoking.

Next: Cataract – Treatment and Surgery Complications.

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