HOW DOES GLAUCOMA DAMAGE YOUR VISION?
When you have glaucoma, pressure will build up in your eye and do irreversible damage to the delicate fibers of your optic nerve. When too much damage is done, the optic nerve will no longer be able to transmit signals from the retina to the brain.
SCREENING FOR GLAUCOMA
During a routine eye exam, your ophthalmologist will perform a series of tests to screen for glaucoma. These tests alone cannot prevent glaucoma from developing, but they allow for early detection and treatment. Typically, during a full glaucoma screening, your eye doctor will perform five tests: tonometry, ophthalmoscopy, perimetry, gonioscopy, and pachymetry.
A tonometer measures the pressure in your eye with either a puff of air or a small device pressed to the eye. The process is not painful, as your eye doctor will give you numbing drops before applying any pressure with the tonometer. If your pressure is within normal range, you most likely do not have glaucoma, but your eye doctor will continue with tests, as early stages of glaucoma can still read at normal pressure levels.
During ophthalmoscopy, your eye doctor will dilate your pupils and shine a light into your eyes to visually examine them. The ophthalmoscope not only lights the eye, but it also magnifies the optic nerve for better examination. If everything appears normal at this point, your eye doctor will not perform any other glaucoma tests.
However, if you are experiencing blind spots or anything appears abnormal during ophthalmoscopy, your doctor will continue on to perimetry, gonioscopy, and/or pachymetry.
PERIMETRY AND GONIOSCOPY
To determine whether you have lost vision due to glaucoma, your eye doctor will perform a perimetry test, passing a light across your peripheral vision. This allows your doctor to map your field of vision.
After your perimetry test, your doctor will perform a gonioscopy test, placing a special contact lens over your iris to study the angle where your iris meets your cornea to determine whether you have open-angle or angle-closure glaucoma. This will determine which treatment is best for your case.
Finally, your eye doctor may perform a pachymetry test to check the thickness of your cornea. Corneal thickness can affect eye pressure test readings. This information will help your doctor get a better idea of the severity of your glaucoma and determine the proper treatment plan for you.
Damage incurred due to glaucoma is permanent, and open-angle glaucoma is almost always painless, gradual, and unnoticeable until it’s too late. You can see, then, why eye doctors are so thorough in their glaucoma screenings.