Glaucoma is an eye disease that causes damage to the optic nerve. In this disease, eye pressure causes damage to the optic nerve fibres that leads to gradual loss of peripheral visual field, finally leading to blindness. Glaucoma is the second leading cause of blindness throughout the world. Vision loss caused by glaucoma is irreversible. It is estimated that half of the population affected by glaucoma may not know that they have the disease.
Although, high pressure within the eye also known as intra-ocular pressure (IOP) is one of the most important risk factor for development of glaucoma, but other risk factors must also be involved because even people with normal IOP can have the disease. It is well known now that glaucoma has to do something with the mechanical compression of the optic nerve or reduced blood flow to the nerve.
Glaucoma is also called as ‘Sneak Thief of Sight’ since there are no warning signs of the disease. Vision loss routinely begins in the periphery. You may compensate for this unconsciously by turning your head on the side of vision loss and may not notice anything until significant central vision is lost. Sometimes patients may experience mild to severe headache, eye pain, and fuzzy vision and may see rainbow colours around light. These symptoms may indicate increase IOP. People who have frequent changes in glass power should also get checked themselves for glaucoma.
There are various risk factors for development of glaucoma which include increasing age, family history of glaucoma, myopia, use of steroids, injury to the eye and uncontrolled diabetes and high blood pressure.
Early detection of the disease through regular and complete eye check-ups is the key to protect you vision from glaucoma. Various eye tests which are done to diagnose glaucoma include following:
- Tonometry to check the pressure within the eye. Applanation tonometer is the most reliable instrument for glaucoma patients.
- Perimetry to check the visual fields
- Gonioscopy to test if the angle inside the eye is open or closed
- Dilated fundus evaluation to see the characteristic glaucomatous changes in the optic nerve head. Sterioscopic fundus photographs can also be done to monitor the changes in optic nerve over years
- Higher imaging modalaties like OCT, GDx, HRT which help in the diagnosis of preperimetric glaucoma
- Pachymetry to measure central thickness of the cornea
Once diagnosed as glaucoma patient, you require lifelong treatment. If detected early, the disease can be successfully controlled, thereby preventing any vision loss. Treatment modalities for glaucoma include eyedrops, lasers and surgeries. Even when medications have successfully controlled the IOP, it is important to monitor the condition by periodical checkups and visual field testings. If despite the medical treatment, glaucoma is not coming under control, surgery can be done to control the pressure, where a new channel is formed in the eye through which the fluid from inside the eye is drained out. Use of antimetabolites during surgery and glaucoma drainage devices (Ahmed glaucoma valve, Express shunt) are the newer advances, which increase the success rate of glaucoma surgery.