Glaucoma: The silent thief of sight that affects millions

KOCHI: Glaucoma is a group of eye diseases that cause damage to the optic nerve, which is the nerve that carries visual information from the eye to the brain. The damage is usually the result of increased pressure within the eye, which can be caused by a build-up of fluid that flows through the eye. It can cause irreversible vision loss and blindness if left untreated.

In India, the burden of glaucoma is 11.9 million, and the prevalence of blindness is 8.9 million. Glaucoma contributes to 12.8 per cent of blindness in India. Epidemiological studies on glaucoma involving adults aged 40 years and above have shown that glaucoma prevalence is between 2.7 and 4.3 per cent among Indians.

Risk

  • Above 40 years of age

  • Certain medical conditions such as hypertension and diabetes

  • Extreme myopia or hyperopia

  • Family history

  • Genetics

  • High intraocular pressure

  • Long-term corticosteroid use

  • Previous eye injury or surgery

  • Thinner corneas

Eye

Types of Glaucoma

There are many types of glaucoma. Each type of glaucoma develops differently, but all of them place your vision at risk.

  • Open-angle glaucoma

    Open-angle glaucoma, or primary open-angle glaucoma, is the most common form. Intraocular pressure rises because the fluid in your eye cannot drain properly. Eye pressure rises because of this fluid build-up, causing damage to the optic nerve. With time, this disease can lead to irreversible vision loss. Often it is detected late as the visual field loss is experienced in the later stage of the disease.

  • Angle-closure glaucoma

    Angle-closure glaucoma is less common. It occurs when the drainage canals are completely or partially blocked. It can progress rapidly or gradually. A completely blocked-off drainage angle is called acute angle-closure glaucoma. This form of the disease is a medical emergency and can cause rapid vision loss. It has several early signs of development such as hazy or blurred vision, severe pain around the eyes and head, redness in the eye, coloured halos around lights, and nausea or vomiting alongside eye pain.

  • Normal-tension glaucoma

    Normal-tension glaucoma causes optic nerve damage without raising your eye pressure. Abnormalities in blood flow to the optic nerve and structural weakness in the optic nerve tissue are potential causes of this problem.

  • Secondary glaucoma

    Secondary glaucoma is a term for any form of glaucoma with an identifiable cause for increased eye pressure. Someone may develop secondary glaucoma due to an eye injury, inflammation, or advanced cases of cataracts or diabetes. Some types of secondary glaucoma include exfoliative glaucoma, neovascular glaucoma, pigmentary glaucoma and traumatic glaucoma.

  • Congenital glaucoma

    Congenital glaucoma is found in babies less than 3 years of age. It is a rare condition but could result in a permanent loss of vision. Symptoms and signs include watery eyes, photophobia (discomfort in bright light) blepharospasm (involuntary movements of the eyelids), enlargement of the eyes (Buphthalmos), hazy cornea and redness of the eye.

Its causes can be varied and they can be a build-up of aqueous humor inside the eye, genetic reasons, birth defects in the ocular angle and underdeveloped cells and tissues.

Diagnosis

  • Medical history

  • Comprehensive eye examination, including:

  • Measuring intraocular pressure (tonometry).

  • Testing for optic nerve damage with a dilated eye examination and imaging tests.

  • Checking for areas of vision loss, also known as a visual field test.

  • Measuring corneal thickness (pachymetry)

  • Inspecting the drainage angle (gonioscopy)

Treatment

The damage caused by glaucoma can’t be reversed. However, treatment and regular checkups can help slow or prevent vision loss, especially if you catch the disease in its early stages.

Glaucoma is treated by lowering intraocular pressure. Treatment options include prescription eye drops, oral medicines, laser treatment, surgery or a combination of approaches. The goal of treatment is to reduce the pressure within the eye and prevent further damage to the optic nerve.

Mind and body

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