Glaucoma WHAT IS GLAUCOMA? Glaucoma results from damage to the optic nerve. Usually the damage is from increased pressure in the eye. The damage to the eye is irreversible and glaucoma can lead to blindness. The most common form, open-angle glaucoma, generally appears in middle age and seems to have a genetic component. In this type of glaucoma, vision loss occurs very gradually. One eye is often worse than the other. Other types of glaucoma are closed-angle glaucoma (a medical emergency) and congenital glaucoma (present at birth). Secondary glaucoma is usually associated with another eye disease or disorder, such as a very mature cataract, uveitis, bleeding, eye tumor, or an eye injury. 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. Variations of OAG include: primary open angle glaucoma (POAG), normal-tension glaucoma (NTG), pigmentary glaucoma, pseudoexfoliation glaucoma, secondary glaucoma and congenital glaucoma. Variations of narrow angle glaucoma include include acute angle closure glaucoma, chronic angle closure glaucoma, and neovascular glaucoma. But as we age, some of the protein may clump together and start to cloud a small area of the lens. This is a cataract. Over time, the cataract may grow larger and cloud more of the lens, making it harder to see. HOW IS GLAUOCMA DIAGNOSED? Since the treatment methods for open angle and angle closure glaucoma are different, it is important to identify the mechanism involved. The diagnosis (or exclusion) of glaucoma requires a detailed and comprehensive eye examination. At our centre doctor will do the following examinations: To detect glaucoma your doctor will do the following examinations: a routine vision test that requires reading letters from a chart, Slit lamp (microscope) examination: This special microscope is the ophthalmologist's stethoscope and all patients, not just those suspected of having glaucoma, must undergo a slit lamp examination. The pressure inside the eye is measured with an 'applanation tonometer' attached to the slit lamp. A hand held version of the instrument is also effective. It may be necessary to obtain multiple readings of the pressure during the course of the day and at night. The older method of resting an instrument on the cornea while the patient lies down is not accurate. The newer non-contact air soft (computerized) instrument may be good for screening but cannot be used for diagnosis or treatment of glaucoma. An examination of the angle of the eye is done with the help of a gonioscope. This is a contact lens placed on the eye to examine the angle of the eye. Its use is mandatory in determining the type of glaucoma - open angle or angle closure. SPECIAL TEST FOR GLAUCOMA? 1. Gonioscopy : With this test the doctor comes to know about the type of glaucoma that the patient is suffering from. A special 'contact lens' called the 'gonioscope' is placed on the eye and the inner structures are visualised using a special microscope called the 'slit-lamp bio-microscope'. This test is not painful and takes a few minutes only. Field Test (Perimetry),Refraction, Although glaucoma cannot be cured it can usually be controlled with proper treatment and regular Eye Check-Ups. When glaucoma is not being adequately controlled with medicines, surgery is necessary, 2. Glaucoma Surgery Surgery involves either laser treatment or making a cut in the eye to reduce the intraocular pressure. The type of surgery your doctor recommends will depend on the type and severity of your glaucoma and the general health of your eye. Surgery can help lower pressure when medication is not sufficient.
