Glaucoma is the leading cause of irreversible visual impairment and blindness across the world. Asia alone accounts for almost 60% of the world’s total glaucoma cases and is home to approximately 4 billion plus people with glaucoma. By 2040, there will be an estimated 53.9% rise in glaucoma cases in Asia. In India as well, 1 in 8 persons above the age of 40 years is either suffering from glaucoma or is at risk of the disease, making this yet another public health challenge.

In view of the disproportionate burden of glaucoma and the rising ageing trends in Asia, there is a need to address this condition without delay. This means ensuring adequate screening measures are put in place and there is easy access to therapeutic options.

Most patients with glaucoma either have open angle or angle closure glaucoma. In both cases, the optic nerve that carries images from the eye to the brain is damaged, usually because of increasing eye pressure, which results in a gradual loss of sight without any warning or recognizable symptoms. Here are 6 important facts to know about the disease:

FACT #1: Glaucoma can affect people at any age, but it usually manifests during middle and old age

Increasing age is an important risk factor for developing glaucoma. Most cases of glaucoma are seen after people cross the age of 40 years. This is when regular eye checks to detect glaucoma must begin. Those greater than 70 years have approximately 3 times the risk as compared to those who are aged 40 years. But it is important to note that glaucoma can affect all age groups: newborns and children (congenital glaucoma) and even young adults.

FACT #2: One type of glaucoma is more prevalent

Globally, primary open angle glaucoma is the more prevalent type of glaucoma and accounts for three quarters of all cases. However, another type of glaucoma known as primary angle closure glaucoma is also prevalent in South East Asia, India, China and Mongolia. The unfortunate reality is that angle closure glaucoma causes blindness in a greater proportion of patients than open angle glaucoma.

FACT #3: There are few or no symptoms of glaucoma in the early stages

For the most part, glaucoma is an asymptomatic disease. The majority of people have open angle glaucoma in which eye pressure increases slowly over time, without any symptoms until there is significant damage to the optic nerve. Angle closure glaucoma is seen in a small proportion of those affected. In those patients, the eye pressure rises abruptly causing symptoms such as headache, vomiting, blurred vision, redness and eye pain which require emergency care. Left untreated, both types lead to peripheral visual field loss which progresses to a ‘tubular field’ in which there is no vision on the sides, finally culminating in total irreversible blindness.

FACT #4: Not all patients with glaucoma have high eye pressure

In the past, eye pressure or intraocular pressure was used as a criterion to diagnose glaucoma. However, today, high eye pressure is considered a major and modifiable risk factor because some patients with glaucoma have normal eye pressure.

FACT #5: Apart from age, other factors also increase the risk of glaucoma

The risk also increases if a person has a family history of glaucoma. Those who have a first degree relative with glaucoma are at a ten times higher risk of the disease.

The risk of glaucoma is also higher in individuals with diabetes mellitus, hypertension and cardiac disease. Other risk factors also include severe near sightedness, being on steroid therapy and a history of physical injuries to the eye.

FACT #6: Regular eye checks are a must to detect glaucoma early

A comprehensive eye examination which includes eye pressure checks, dilated retinal evaluation to assess the optic nerve damage and visual field assessment with specialized equipment is mandatory to diagnose glaucoma. Once diagnosed, vision that is already lost because of glaucoma cannot be recovered but with the appropriate treatment, further deterioration of vision can be prevented. Early diagnosis and regular treatment can slow down glaucoma progression, and those over the age of 65 years should go for an eye check at least once every 1 to 2 years.