Glaucoma cannot be prevented, it can certainly be controlled, says Dr Mahipal Singh Sachdev, Chairman, Centre for Sight group of eye hospitals.

On being asked how Glaucoma affects the vision, Dr Sachdev said it occurs due to the rise in intraocular pressure which damages the optic nerve and thereby affects vision. Aqueous, the fluid that nourishes the front part of the eye, is also responsible for the regulation of its drainage that is helpful in maintaining the ocular pressure. This increased pressure damages the optic nerve, which is the conduit of visual messages to the brain.

Factors such as increasing age, trauma to the eye, or any other ailment, are responsible for blocking the fluid to raise the pressure inside the eye. He said Glaucoma is often described as the silent thief of sight because there may not be any symptoms of this condition in the early stages. This condition threatens vision and is known to gradually steal sight without warning. By the time Glaucoma is detected, the patient has already suffered extensive peripheral vision damage which can no longer be restored.

Glaucoma is the leading cause of blindness in the United States and a study presented at the World Ophthalmological Congress in 2008 has predicted spread of Glaucoma at a rapid rate in India. Almost 68 per cent Indians run the risk of developing the disease and nearly 1.2 lakh Indians go blind every year due to this disease. 'You are at risk, if you are 45 years of age or above, you have a family history of Glaucoma and have health problems such as diabetes, hypertension or thyroid disorder, myopia or nearsightedness and ocular trauma or have had intra ocular surgery in the past.'

There are two major types of Glaucoma - Chronic or Primary Open- Angle Glaucoma (POAG) and Closed or Acute Angle-Closure Glaucoma. The chronic open angle form of Glaucoma is the most common form. Damage to vision is gradual and generally painless. In the Closed or Acute form, the intra ocular pressure increases very rapidly due to a sudden and severe block of fluid drainage within the eye. Significant symptoms indicating the presence of acute glaucoma appear immediately. This condition has to be treated quickly by an ophthalmologist otherwise blindness may occur.

Possible symptoms of Glaucaoma are inability to adjust the eyes to darkened rooms such as theaters, poor night vision, frequent changes in eyeglass prescription, gradual loss of peripheral vision, blurred vision, feeling of a blind area in the eye, seeing rainbow colored halos around lights, severe eye pain, facial pain, nausea and vomiting and Red eye.

Glaucoma cannot be cured but it can be controlled so that further damage to the optic nerve can be slowed down or halted. This can only be done through disciplined and regular treatment from an ophthalmologist. The treatment of Glaucoma is life-long.

Glaucoma treatment may include medical management, surgical management or management by lasers. Medical management is done with eye drops. Surgical management includes a procedure where an opening is made to create a new drainage pathway for the fluid to leave the eye easily.