Glaucoma is a general name for a group of eye diseases that damage the optic nerve of the eye.
Glaucoma is often called “the thief of sight” because glaucoma symptoms either go undetected or develop slowly over time. Glaucoma usually starts by attacking the outside of your vision. Left untreated, glaucoma can lead to complete blindness in one or both eyes.
The most common eye problem linked to glaucoma is an increase in internal eye pressure. An increase in internal eye pressure doesn’t automatically mean you “have” glaucoma; only that you have a condition that could lead to it—that’s why a regular exam is so important.
Glaucoma typically affects your peripheral vision first. This is why it is such a sneaky disease: You can lose a great deal of your vision from glaucoma before you are aware anything is happening. If uncontrolled or left untreated, glaucoma can eventually lead to blindness.
Detection of Glaucoma
During routine eye exams, a tonometer is used to measure your intraocular pressure (IOP). Your eye typically is numbed with eye drops, and a small probe gently rests against your eye’s surface. Other tonometers direct a puff of air onto your eye’s surface to indirectly measure IOP.
An abnormally high IOP reading indicates a problem with the amount of fluid inside the eye. Either the eye is producing too much fluid, or it’s not draining properly.
Another method for detecting or monitoring glaucoma is the use of instruments to create images of the eye’s optic nerve and then repeating this imaging over time to see if changes to the optic nerve are taking place, which might indicate progressive glaucoma damage. Instruments used for this purpose include scanning laser polarimetry (SLP), optical coherence tomography (OCT), and confocal scanning laser ophthalmoscopy.
Visual field testing is another way to monitor whether blind spots are developing in your field of vision from glaucoma damage to the optic nerve. Visual field testing involves staring straight ahead into a machine and clicking a button when you notice a blinking light in your peripheral vision. The visual field test may be repeated at regular intervals so your eye doctor can determine if there is progressive vision loss.
Instruments such as an ophthalmoscope also may be used to help your eye doctor view internal eye structures, to make sure nothing unusual interferes with the outflow and drainage of eye fluids. Ultrasound biomicroscopy also may be used to evaluate how well fluids flow through the eye’s internal structures. Gonioscopy is the use of special lenses that allow your eye doctor to visually inspect internal eye structures that control fluid drainage.
Depending on the severity of the disease, treatment for glaucoma can involve the use of medications, conventional (bladed) surgery, laser surgery or a combination of these treatments. Medicated eye drops aimed at lowering IOP usually are tried first to control glaucoma.
If you find that the eye drops you are using for glaucoma are uncomfortable or inconvenient, never discontinue them without first consulting your eye doctor about a possible alternative therapy.
All glaucoma surgery procedures (whether laser or non-laser) are designed to accomplish one of two basic results: decrease the production of intraocular fluid or increase the outflow (drainage) of this same fluid. Occasionally, a procedure will accomplish both.
Currently the goal of glaucoma surgery and other glaucoma therapy is to reduce or stabilize intraocular pressure (IOP). When this goal is accomplished, damage to ocular structures – especially the optic nerve – may be prevented.