Coping with glaucoma4 min read . Updated: 10 Mar 2014, 06:06 PM IST
World Glaucoma Week ends on 15 March. Understand how this condition works and take precautions to prevent it from robbing you of the power to see
When a Delhi-based, 38-year-old country manager with a consumer goods company felt his vision blurring before an important sales meeting in September, he panicked. On closing his right eye, he could see the numbers, but when he closed the left eye everything was dark. After several attempts, he realized that he could not see out of his right eye. He visited an eye specialist and was diagnosed with severe glaucoma in the right eye, with slight damage in the left eye.
Awareness about glaucoma, usually an inherited condition, is scarce. The condition sneaks up suddenly, leading to irreversible eyesight loss if not treated in time. Perhaps one reason it is not treated in time is because its symptoms are rather vague (see “Symptoms" below). “In fact, population-based studies report that more than 90% of glaucoma in India is undiagnosed," says Devindra Sood, director and head, glaucoma services, Eye-Q Super Speciality Eye Hospitals, Gurgaon. In India, it is estimated that glaucoma affects 12 million people, accounting for 12.8% of the country’s blindness, and by 2020, the number is expected to reach 16 million, says the Glaucoma Society of India. “Also, it is a myth that it is an old man’s disease. Glaucoma can affect any age group, including newborns, infants, children and elderly," says Dr Sood.
How it happens
“In glaucoma, the optic nerve (the nerve of sight) slowly gets damaged, most often due to raised pressure in the eye, leading to slow and progressive loss of field of vision," explains Girija Suresh, senior consultant, ophthalmology, Fortis Hospital, Mulund, Mumbai.
Glaucoma generally results from the failure of the eye to maintain an appropriate balance between the amount of internal (intraocular) fluid produced and the amount that drains away. “Just as a basketball or football requires air pressure to maintain its shape, the eyeball needs internal fluid pressure to retain its globe-like shape and ability to see. But unlike a ball or balloon, the eye can’t relieve pressure by springing a leak and ‘deflating’ when pressure is too high. As the pressure rises, the blood supply to the optic nerve is reduced and eventually nerve fibres are permanently damaged and vision is lost," says Shashank Rai Gupta, senior consultant, vitreo-retina, uveitis and diabetic eye care, Vasan Eye Care Hospital, Delhi.
Catch it in time
As blindness from glaucoma is irreversible, early detection is the key to preserving vision. “The biggest concern in diagnosing glaucoma is that it usually has no symptoms in the early stages. Also, when symptoms develop, they mimic other conditions. For example, blurred vision can happen with cataract too. While the vision loss from cataract can be restored by surgical removal of the opaque lens, in the case of glaucoma it cannot be reversed (only halted)," says Dr Sood.
To detect glaucoma, the TOP-G test is conducted (tonometry to assess the eye pressure; ophthalmoscopy to look at the optic nerve at the back of the eye; perimetry, a computerized test to assess the field of vision; gonioscopy involves a special contact lens being placed over the eye to look at the fluid outflow facility. “OCT (ocular coherence tomography) and measurement of central corneal thickness (pachymetry) are the tests that detect the level of glaucomatous damage," adds Dr Suresh.
“Glaucoma in the family, diabetes, thyroid disease or hypertension, taking medication for sleep/anxiety/depression/asthma/Parkinsonism, injury to the eye, high myopia or arbitrary and overuse of steroid eye drops may up the risk for the disease," warns Dr Sood.
People with high risk factors should consult an ophthalmologist every year after the age of 35 and even if there are no risk factors or overt symptoms, follow this schedule for eye examinations: Every two-four years before age 40, every one-two years from age 40-60 and every six-12 months from age 60 onwards.
“A majority of the patients can be treated simply with eye drops, which need to be continued lifelong. And if that doesn’t lower the eye pressure to the desired level, glaucoma surgery might be required. Laser treatment is done in some cases, and sometimes traditional surgery to help the eye drain fluid might also be conducted," says Dr Suresh.
“In the case of the 38-year-old country manager, a non-invasive laser procedure was done and he was advised regular eye drops (to continue lifelong). Although eyesight in the right eye could not be reverted, progression of damage to the left eye was halted completely and he could resume work," says Dr Sood.
“With an expected increase in population and longevity, glaucoma is likely to become a major cause of ocular morbidity (blindness) in the coming years. Only awareness and regular checks-ups can help rein in the numbers," says Dr Sood.
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The presence of these signs may not mean that you have glaucoma but they do warrant a comprehensive eye examination:
u Decreased side vision
u Sudden hazy or blurred vision
u Haloes or rainbows around light
u Pain in the eye and headache
u Frequent change in glass power
u Vomiting with headache and eye pain.
—Shashank Rai Gupta, senior consultant, vitreo-retina, uveitis and diabetic eye care, Vasan Eye Care Hospital, Delhi.