Glaucoma is the second leading cause of blindness in the world, according to the World Health Organization [WHO]. It is a group of eye diseases that steals eyesight without warning. Moreover, no symptoms show up in the early stages of the disease. Glaucoma damages the optic nerve. In many cases, this damage is associated with a rise in pressure within the eye, which could lead to blindness. A clear fluid called aqueous humor produced inside the eye has to flow out of the eye through the angle. When the outflow of aqueous humor gets blocked, pressure inside the eye increases. The sustained increase in the pressure causes glaucoma. Yet many people with normal pressure can also lose sight to this disease.
Everyone is at risk for glaucoma from babies to senior citizens. Yes, older people are at a higher risk for glaucoma but babies can be born with glaucoma [approximately one out of every 10,000 babies born in the United States have glaucoma]. Young adults can get glaucoma, too. Repeated studies in developed nations have shown that nearly half of those suffering from glaucoma do not know they have the disease. More shocking are the news printed in two American publications which state that 65-75 per cent of people suffering from glaucoma are undiagnosed.
Some groups are at a higher risk than others. A well-designed research shows that siblings of persons diagnosed with glaucoma have nearly a 10-fold chance of having glaucoma when compared to siblings of persons without glaucoma. Siblings of glaucoma sufferers can benefit from regular eye examinations and careful screening for glaucoma.
Research indicates 20 per cent of people over 75 years of age are at risk. Clearly they need regular eye checkups for glaucoma. Other high-risk groups include: people over 60, family members of those already diagnosed, diabetics, and people who are severely nearsighted.
Glaucoma is not curable, and vision lost cannot be regained. With medication and/or surgery, it is possible to halt further loss of vision. Since glaucoma is a chronic condition, it must be monitored for life. Diagnosis is the first step to preserving your vision.
Regular eye examinations are the best form of prevention. In general, get your eyes checked for glaucoma:
- before age 40, every 2-4 years
- from age 40-54 years, every 1-3 years
- from age 55-64 years, every 1-2 years
- after age 65, every 6-12 months.
Anyone at high risk should be tested every year or two after age 35. While there are no known prevention methods, blindness or significant loss of vision from glaucoma can be prevented if detected in the early stages.
In its most prevalent form—primary open angle glaucoma—vision loss is silent, slow, and progressive. It affects the peripheral vision [side vision] first and progresses until central vision is lost. Glaucoma medications slow the progress of the disease by reducing the elevated intraocular pressure [IOP] to prevent damage to the optic nerve. Surgical treatments are also available.
Types of glaucoma
There are two main types of glaucoma, primary open angle glaucoma [POAG], and angle closure glaucoma [ACG]. Both are marked by an increase of pressure inside of the eye causing damage to the optic nerve. Optic nerve damage due to normal eye pressure is called normal tension glaucoma. Secondary glaucoma refers to any case where another disease or ailment causes increased eye pressure, resulting in optic nerve damage.
Search for a cure
There is no cure for glaucoma, but proper treatment which includes medication or surgery can slow the progress of the disease. Understanding what causes glaucoma is the first step in finding a cure. Non-profit organisations like the [GRF] Glaucoma Research Foundation continuously provide funding for research on glaucoma. Some key research studies by the GRF include the Collaborative Normal Tension Glaucoma Study, which was the first controlled clinical trial to establish that lowering eye pressure preserves vision. The Catalyst For a Cure, is a consortium of specialists in genetics, nerve regeneration, and neurodevelopment working in real-time to understand neuronal loss in glaucoma and identify targets for intervention. National Eye Institute and industry also fund important research to unlock the mysteries of glaucoma and find better treatments.
- Early diagnosis and treatment is key in preventing vision loss from glaucoma.
- If any family member has glaucoma, then you are at a greater risk. Talking to family members about glaucoma helps in knowing about dealing with it.
- If you have diabetes or high blood pressure, you are at risk of developing glaucoma.
Keeping a check: How to go about your eye check-up
What does a routine eye examination involve?
Routine eye examination involves checking the vision for both near and distance, looking for refractive errors that can be corrected with glasses, testing the muscle balance, detailed physical inspection of the front of the eye using magnification, checking eye pressure [intraocular pressure], and examining the retina using tools such as ophthalmoscope.
How frequently should you have a routine examination?
You are in good health if you need examination only once a year or two. There are certain diseases that are detectable only on examination and the person suffering from the same may not have any symptoms related to the disease.
Who should go for a closer periodic follow up?
Diabetes affects the retina. So diabetics need periodic follow up even if they are not symptomatic. Those belonging to families in which hereditable eye diseases are present too should go for routine evaluation. As also, patients who are highly myopic.
Are there regular medications that keep the eyes healthy?
You don’t need medications unless you have a disease to be controlled or treated. No special vitamins or drugs are required as long as you have a balanced diet. Vitamin supplements may be prescribed in certain diseases like Age Related Macular Degeneration but an otherwise normal person does not need supplements.
By Dr LS Varadharajan, faculty and researcher at Elite School of Optometry, a unit of Medical Research Foundation, Sankara Nethralaya.
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