Glaucoma is the second most common cause for blindness globally, accounting for almost 8% of blindness cases. It is rightly labelled as the “silent thief of sight”, as in this condition the person experiences complete visual impairment with no apparent symptoms, often causing them to go undiagnosed until irreversible vision loss.
There are various treatments to delay the loss of vision but there is no complete cure for this disease, making it one of the leading causes for blindness globally. In India, over 11.2 million people are diagnosed with glaucoma, yet only 10% of the population is aware of this dreaded disease.
In glaucoma, the optic nerve is damaged at the point where it leaves the eye. This optic nerve carries information from the light-sensitive layer in your eye, the retina, to the brain where it is perceived as a picture. There are often no early symptoms, which is why 50% of people with glaucoma are unaware of their condition. The symptoms progress gradually, so one may not notice a change in vision until the condition is at an advanced stage.
Vision loss due to glaucoma cannot be reversed, hence, it is important to have regular eye exams that include measurements of eye pressure, so a diagnosis can be made in its early stages and treated appropriately.
There are various risk factors that can trigger this disease such as being over 60 years, family history of glaucoma, having high internal eye pressure or intraocular pressure, certain medical conditions such as diabetes, heart disease, high blood pressure and sickle cell anaemia, prior eye injury, less central corneal thickness, taking corticosteroid medications, especially eyedrops, for a long time etc.
Today, glaucoma is the second leading cause of blindness for people over 60 years of age after cataract. However, the disease is known to occur at any age but largely found in older adults.
There are two types of glaucoma: narrow-angle glaucoma and open-angle glaucoma. The latter is the most common form, which results in increased eye pressure. In this, the patient doesn’t experience obvious symptoms, but the eye’s drainage canals get clogged over a period of time, causing an increase in internal eye pressure and subsequently causing damage to the optic nerve.
Narrow-angle glaucoma occurs suddenly when the coloured portion of the eye is pushed or pulled forward. This causes blockage in the internal eye structures leading to internal pressure, and resulting in extensive damage on the optic nerve.
In open-angle glaucoma, symptoms vary depending on the stage of the disease but these are few of the signs to watch out for, such as patchy blind spots in peripheral or central vision and tunnel vision. In narrow-angle glaucoma, symptoms include severe headaches, nausea and vomiting, eye pain and redness, blurred vision etc.
It is important to be sensitive to these potential symptoms so that we can identify the condition at the earliest stage. Unfortunately, if glaucoma is left untreated, it will eventually cause blindness. Even with treatment, about 15% of patients with glaucoma become blind in at least one eye within 20 years.
Acting early
These self-care steps can help one detect glaucoma in its early stages, which is important in preventing vision loss or slowing its progress.
• Get regular dilated eye examinations: Regular comprehensive eye exams can help detect glaucoma in its early stages before significant damage occurs. As a general rule, the American Academy of Ophthalmology recommends having a comprehensive eye exam every 5 to 10 years, if you’re under 40 years old; every 2 to 4 years if you’re between 40 and 54 years old; every 1 to 3 years if you’re between 55 to 64 years old; and every 1 to 2 years if you’re older than 65.
• Know your family’s eye health history: Glaucoma tends to run in families. If you’re at risk of glaucoma, you will need more frequent screening.
• Working your eye: Regular and moderate eye exercise may help prevent glaucoma by reducing eye pressure.
• Take prescribed eyedrops regularly: Glaucoma eyedrops can significantly reduce the risk of high eye pressure progressing to glaucoma. To be effective, eyedrops prescribed by your doctor needs to be used regularly even if you have no symptoms. Discontinuing the medication on your own, not following the doctor’s advice and irregular checkups are the commons mistakes patients make. Once diagnosed, glaucoma needs lifelong treatment.
(The writer is Consultant Ophthalmologist, BGS Gleneagles Global Hospitals)
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