Glaucoma, otherwise known as "Kala Motia" is an eye disease in which there is an increase in pressure inside the eye. Just as some people have high blood pressure, in the same way a glaucoma patient has high eye pressure.
If the eye pressure remains high for a long time it damages the optic nerve which carries the light sense from the eye to the brain. This damage to the nerve is irreversible and leads to permanent and incurable blindness. That is why glaucoma is a dangerous disease of the eye and has been labeled as "lurking thief of vision". Glaucoma is the second leading cause of blindness in the world with 70 to 105 million people affected worldwide (WHO).
Damage due to glaucoma is preventable, not curable. It is therefore necessary that the disease should be detected and treated at its earliest stage to prevent blindness.
Glaucoma is usually asymptomatic or is associated with very mild symptoms which the patient often tends to ignore. Some of the early symptoms include:
Although glaucoma is most common above the age of 40 years, it may affect any age group. A special type of glaucoma called Congenital Glaucoma may affect even a newborn or a child. Any eye that appears bigger than normal in a child should be shown to an eye specialist.
There are three main varieties of glaucoma in adults which concern us:-
Let us explain with the simple example of a kitchen sink at your home. There is a tap through which water comes and there is a drain through which water, after cleaning utensils, is drained off. If the drain is blocked, water accumulates in the sink. Similarly, in your eye there is an area which produces a clear fluid which circulates inside the eye and provides oxygen and nourishment to the vital parts. Likewise, there is a small drainage channel through which all the waste products from inside the eye are drained. In glaucoma this passage or the drainage channel is blocked, either at its entrance or beyond. When the block is at the entrance it is called Closed Angle Glaucoma. When the blockage is not at the entrance, but beyond, somewhere inside, we call it Open Angle Glaucoma. The blockage results in more fluid accumulating inside the eye than can be drained out. This leads to a buildup of high pressure inside the eye.
Since glaucoma more often affects the side vision, the central vision may be retained till a very advanced stage. It is important to remember that a good central (straight ahead)vision test may mislead a glaucoma patient about theseverity of glaucoma and the extent of damage to the optic nerve.
This is done by tonometry (non-contact/applanation). This helps your doctor to determine how high your pressure is and how well the medicine is controlling it.
By ophthalmoscopy and optic nerve photography.
A special magnifying contact lens is used on your eye to help your doctor determine why the fluid is not draining properly. This examination is called gonioscopy
This test detects defects in your central and peripheral field of vision.
These special tests measure the thickness of the nerve fibre layer and helps your doctor detect glaucoma at a very early stage.
As damage to nerve caused by glaucoma cannot be reversed, the aim of the treatment is to prevent or reduce further damage to the optic nerve. The first step to do that is to lower the eye pressure. The three modalities of treatment are:-
Your doctor will prescribe you certain medication (Eye drops and tablets) so as to lower your eye pressure. " You must use the medicines regularly as directed by your ophthalmologist. You should not stop medicines even if you do not have symptoms. A regular follow up, as advised by your doctor, is mandatory.
If glaucoma is not controlled with the help of medicines, if the side effects of the medicines are not well tolerated and the patient is non compliant, or cannot afford the cost of the medicines, the second option is LASER TREATMENT. There are various types of lasers that are used in the treatment of glaucoma.
A small opening is made in the iris so that the stagnant fluid finds a way to the anterior chamber, the front portion of the eye, and subsequently drained off. This is an OPD procedure, done under local anesthetic drops and takes only a few minutes to be completed. After the laser, you can wash your eye with water and can lead a normal life.
This is a new type of laser, which does not cause any thermal burn in the eye and may be called "COLD LASER". It stimulates the autoimmune system of the eye to clear the block in the drainage area without damaging the surrounding delicate tissues. SLT is a painless OPD procedure, which takes a few minutes to be completed. One can resume normal activities immediately after the laser. If necessary it can be safely repeated without damaging the eye.
When applied at the drainage area, the laser causes small burns, which contract to open up the block.
In this the laser is applied on the area, which produces fluid in the eye. It can be used if the IOP is too high and is intractable.
Your treating doctor will decide which laser is suitable for you.
Operation for glaucoma is the only option left for patients in whom the eye pressure is not controlled with medication or laser. It is also the treatment of choice in non-compliant patients, and in infants and children with glaucoma. Filtering microsurgery involves creating a drainage hole with the use of a small surgical tool, to bypass the blockage in the eye's trabecular meshwork (the eye's drainage system). This opening helps increase the flow of fluid out of the eye and thereby reduce the eye pressure.