Glaucoma is the second leading cause of blindness in the world and the most common cause of irreversible blindness globally. (Most common cause of blindness is Cataract which is reversible). It is estimated that 4.5 million person globally are blind due to glaucoma, and that will rise to 11.2 million by 2020.
It silently robs your eye sight even before you feel it. It happens due to progressive damage of the Optic Nerve which is irreversible. However early detection and treatment of Glaucoma can halt or slowdown any further vision loss. Therefore early detection is the key to prevent progression of disease towards severe visual handicap or blindness. The earlier the diagnosis optic nerve damage is less and visual impairment can be minimized or prevented.
To fight against something devastating, we should know what it is.
Glaucoma is a group of eye disease that cause progressive damage of the optic nerve in the eye which carries visual information to the brain. Your eye has a circulation which maintain the eye pressure to keep the eye in shape and function properly. Main reason for the damage of optic nerve is raised eye pressure. Eye pressure is maintained by a watery fluid called Aqueous. Aqueous is produced by a structure called ‘ciliary body’ in posterior chamber (posterior part) of the eye. The fluid passes through the pupil (hole in the centre of Iris) to the anterior part of the eye where it leaves the eye by draining through a sieve like structure in the angle of the eye between cornea and iris to the blood stream.
Normally there’s a balance between the aqueous production and drainage. But, if it is produced too much or the draining pathway is blocked, eye pressure will rise. When the optic nerve is under too much pressure persistently, it damages gradually. A significantly acuterise of eye pressure can damage optic nerve immediately. Eye pressure is independent of blood pressure. On the other hand aqueous fluid which is responsible for eye pressure has nothing to do with tears. Those are the misconceptions among the public.
You can get your eyes checked by a specialized eye unit. Specialized eye unit available in all Tertiary care hospitals, all General hospitals and some Base hospitals. In private sector also private hospitals and some consultation centres have facilities to check eyes. Doctor will check your eye pressure and Ophthalmoscopic examination of the fundus to check the optic nerve. Then your doctor might order some tests to confirm the diagnosis and the extent of the disease.
Visual Field Tests are the most common widely using basic test for Glaucoma, Humphrey Visual Field (HVF) test is the most common variety being used. A Visual Field maps out what your area of vision looks like to you. This detects the invisible areas to the patient which has gone unnoticed by the patient until the damage is severe.
This test is helpful in diagnosing and to detect the disease progression with time. With the advent of the new technology a non-invasive computer based 2D and 3D imaging tests are introduced, which are called Optical Coherence Tomography (OCT). It uses light waves to take cross sectional pictures of your Retina enabling a detailed view. This is more advanced and sensitive method. Unfortunately this is not widely available in government hospitals, although it is available in some Tertiary Care Hospitals including National Eye Hospital, Colombo and Teaching Hospital, Kandy.
Once the diagnosis of Glaucoma has been made, mainstay of treatment is controlling the eye pressure. Reducing 1mmHg (unit) even has a greater impact on protecting the Optic Nerve and thereby protecting visual loss. Once Glaucoma is diagnosed the treatment should be lifelong. Your doctor will prescribe you one or two eye drops, rarely may be a pill added. According to the extent of the disease you will be asked to get your eye pressure checked in regular interval. You should go for the follow up in recommended interval by your doctor. If the desired level of reduction of eye pressure not achieved by drugs, laser treatment or a surgery might needed in later stage. If you are diagnosed to have Glaucoma you should tell your close family members also to get the eyes checked for Glaucoma.
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