India can easily be the world’s capital of glaucoma, a group of eye disorders that leads to irreversible blindness, with the disease affecting 12 million people, and remaining undiagnosed in over 90% of the cases.
Increasing population of senior citizens, diabetics and people with refractive errors, the known potential risk factors, are set to make glaucoma a rapidly emerging non-communicable ocular disease in the country, which already houses 20% of the world’s blind and in this article let us know how to prevent severe eye condition.
Unfortunately, there are no known measures to prevent glaucoma. The only way to prevent blindness from glaucoma, which shows no symptoms in the early stage, is early diagnosis and treatment that could halt the progression of this silent thief of sight.
Nearly 40 million people in India, including 1.6 million children, are blind or visually impaired. Next to cataracts, and untreated refractive errors, glaucoma is the third leading cause of blindness in India. However, glaucoma is more complex and dangerous as the sight loss caused by it is progressive and, unlike cataract, is irreversible. Glaucoma is both under-diagnosed and under treated. It occurs when the pressure inside the eye (intraocular pressure) increases. The pressure is normal so long as the rate of production of aqueous humor, the clear liquid inside the front part of eyes, matches the rate of its drainage. However, when the channels carrying this fluid get blocked, the pressure inside the eye increases.
This increased pressure damages the optic nerve, which passes the visual messages to the brain.
There are two major types of glaucoma: open angle glaucoma, and close angle glaucoma. Open angle glaucoma is the most common form of glaucoma. It accounts for at least 90% of all glaucoma cases It progresses very slowly and the patient may not feel any loss of vision until it affects the central vision. This results in permanent damage if the patient does not get an eye check-up.
Glaucoma can strike one at any age - it is reported that people have about 2.3% lifetime risk of glaucoma. However, those who are over 40 years, and who have a family history of glaucoma, and diabetics, and people with refractive errors and those who take steroid medications, eye drops, pills, inhalers, and skin creams are considered at risk populations. They should screen for glaucoma, every year.
When diagnosed early, glaucoma can be treated effectively to avoid or minimize vision loss. Diagnosis is divided into two categories: clinical examination and diagnostic testing.
Clinical examination involves the assessment of the eye with specialised equipment such as slit lamp biomicroscopy, tonometer, and gonioscopy. Diagnostic tests include perimetry, pachymetry, photography of the optic nerve head, optical coherence tomography, scanning laser polarimetry and confocal laser scanning ophtalmoscope.
Since intraocular pressure is the only modifiable factor in glaucoma, treatment modalities revolve around normalisation of this pressure. Types of treatment can be medical (eye drops, tablets ) laser therapy (aimed at opening of blocked channels) and surgical (aimed at the creation of new channels for draining the fluids inside the eye).
Surgical correction also includes a variety of devices that can be placed to help with the drainage from the eye.
The main objective of World Glaucoma Week is to eliminate glaucoma blindness by motivating people to have regular eye check up, including optic nerve examination. The 2021 theme is “The world is bright, save your sight!”
It reflects the hope that with regular testing, people continue to see the world around us: full of beauty, charm, and adventure.
Dr. R Kaladevi, MBBS, MS is the Regional Medical Director, Dr Agarwals Eye Hospital, Chennai