What is Glaucoma ?
Glaucoma refers to a group of related eye disorders that all cause damage to the optic nerve that carries information from the eye to the brain. Glaucoma usually has few or no initial symptoms.
In most cases, glaucoma is associated with higher-than-normal pressure inside the eye, but it also can occur when intraocular pressure (IOP) is normal. If untreated or uncontrolled, glaucoma first causes peripheral vision loss and eventually can lead to blindness.
Glaucoma is the second-leading cause of blindness worldwide (behind cataracts).
Types of Glaucoma
The two major categories of glaucoma are open-angle glaucoma (OAG) and narrow angle glaucoma. The “angle” in both cases refers to the drainage angle inside the eye that controls the outflow of the watery fluid (aqueous) that is continually being produced inside the eye.
If the aqueous can access the drainage angle, the glaucoma is known as open angle glaucoma. If the drainage angle is blocked and the aqueous cannot reach it, the glaucoma is known as narrow angle glaucoma.
Primary open-angle glaucoma.(POAG) This common type of glaucoma gradually reduces your peripheral vision without other symptoms. By the time you notice it, permanent damage already has occurred.
If your IOP remains high, the destruction caused by POAG can progress until tunnel vision develops, and you will be able to see only objects that are straight ahead. Ultimately, all vision can be lost, causing blindness.
Acute angle-closure glaucoma. Also called narrow-angle glaucoma, acute angle-closure glaucoma produces sudden symptoms such as eye pain, headaches, halos around lights, dilated pupils, vision loss, red eyes, nausea and vomiting.
The other types include Normal-tension glaucoma, Pigmentary glaucoma and lens induced glaucoma
Who Is at Risk?
People > 35 years of age with family history of glaucoma are at maximum risk of developing glaucoma. People with Diabetes, hypertension, Smokers are also at risk of developing Glaucoma
Glaucoma often is called the “silent thief of sight,” because most types typically cause no pain and produce no symptoms until noticeable vision loss occurs.
For this reason, glaucoma often progresses undetected until the optic nerve already has been irreversibly damaged, with varying degrees of permanent vision loss.
But with acute angle-closure glaucoma, symptoms that occur suddenly can include blurry vision, halos around lights, intense eye pain, nausea and vomiting. If you have these symptoms, make sure you see an eye care practitioner or visit the emergency room immediately so steps can be taken to prevent permanent vision loss.
How can one diagnose glaucoma ?
During routine eye exams, a tonometer is used to measure your intraocular pressure, or IOP. This is followed by examination of Optic Disc, gonioscopy to look at the angles of the eye. Visual field testing is done to assess the loss of peripheral vision (if any). Now a days OCT is being used to quantify the thickness of the retinal nerve fibres that carry vision to the brain.
Treatment can involve glaucoma surgery, lasers or medication, depending on the severity. Eye drops with medication aimed at lowering IOP usually are tried first to control glaucoma.
Because of painless nature of the disease, people may become careless about strict use of eye drops that can control eye pressure and help prevent permanent eye damage.
Non-compliance with a program of prescribed glaucoma medication is a major reason for blindness caused by glaucoma.
One should never discontinue them without first consulting your eye doctor about a possible alternative therapy.