Glaucoma is buildup of fluid pressure in the eye. The fluid called aqueous humor normally flows out of the eye through a mesh-like channel. When the channel is blocked, the fluid is accumulated in the eye building up pressure leading to damage to the optic nerve and vision loss.
Glaucoma is the prominent and leading cause for total blindness.
Glaucoma is classified into two types. They are open-angle glaucoma and closed – angle glaucoma. When the angle between the iris and cornea is too narrow preventing flow of fluid it is called closed angle glaucoma.
Open angle glaucoma is slow exit of the fluid aqueous humor through the mesh. Closed angle glaucoma is total blockade of the fluid by the iris.
Sudden buildup of pressure due to closed angle glaucoma leads to farsightedness and cataract.
Mostly people are affected only by open angle glaucoma where the vision loss is very gradual taking many years. There may not be any noticeable sight problems to indicate that a person is affected. It is found out only after the problem has reached an advanced stage.
The pressure developing in the eyes is called intraocular pressure and such pressure continuing over a period of time can damage the optic nerve which transmits messages to the brain. When the optic nerve remains damaged for a longer time total vision loss may occur.
Normally glaucoma develops gradually over a period of time, say many years. But there are possibilities of sudden glaucoma also due to injury to the eye, severe infection of the eye or chronic inflammation of the eye.
Glaucoma normally affects a person after middle age and in most cases the cause is only hereditary. But the fact is that Glaucoma can affect people of all ages including infants and children more particularly when there is a family history of glaucoma. Whether a person is affected by glaucoma can be found out only at the advanced age even though there is family history of the disease. People who are diabetic and on steroids and people who are affected by other eye diseases are vulnerable to glaucoma.
Generally there are no early symptoms that indicate a person is affected by glaucoma. It can be found out by only periodical medical tests. But when the disease has developed many symptoms may surface based on the type.
In the case of open angle glaucoma, symptoms that appear are:
- Blind spots with patches in the peripheral and side vision
- In the advanced stages tunnel vision is experienced.
In the case of closed angle glaucoma, the symptoms are, pain in the eyes, blurred vision, chronic headache, vomiting sensation and nausea.
Glaucoma is diagnosed by a doctor by conducting various laboratory tests. They are:
- Dilating the pupil
- Check the optic nerve for any damage
- Tonometry test or intra ocular test to check the eye pressure which indicates the level of fluid accumulation
- Conduct a visual field test to find our loss of central or peripheral vision
- Pachymetry to measure corneal thickness
- Gonioscopy to check the angle i.e. passage of fluid
Treatment of glaucoma
Once diagnosed, the treatment given is based on the type of glaucoma and the extent of seriousness as revealed by various tests conducted.
Treatment involves several steps like:
- Increasing the flow of fluid through the angle
- Decreasing the production of the fluid itself
- Reduce the eye pressure
- Contain the damage to the optic nerve further
- Regular checkups to monitor the progress of recovery and slowing down the damage process
- In the initial stages eye drops are used and then medicines for oral consumption
- If the disease is still not restricted then surgical procedures can be adopted.
Surgery as a treatment
Some of the surgical procedures generally undertaken are:
- Trabeculoplasty: Drainage canals are unblocked by using high energy laser beam to facilitate free flow of fluid outside and to reduce the inner pressure of the eye. This is not a onetime surgery but the process may have to be repeated periodically depending upon the abatement of the issues.
- Filtering surgery: If the trabeculoplasty surgery is not working another surgical procedure called trabeculectomy is performed. Here the surgeon makes a small opening in the white of the eye to remove some mesh in order to facilitate free flow of fluid.
- For children or those with secondary glaucoma, a small silicon tube is inserted into the eye to drain the fluid. This process is called aqueous shunt implant or drainage implant.
If a person is affected by glaucoma even if in only one eye, both the eyes are tested and diagnosed and then treated because glaucoma is known to affect both eyes invariably.
Glaucoma is irreversible and there is no total cure. All treatments are towards preventing escalation of the disease and slow down the process of damage.
Prevention of glaucoma is not possible but early checkup and treatment can defer damage and preserve the eye sight for a longer time. While getting glaucoma may be inevitable, early diagnosis and treatment can protect the eyes from further damage.