Glaucoma Testing - What To Expect During Your Eye Exam

Glaucoma is an eye disease that results in damage to the optic nerve. This nerve transmits images from the eye to the brain and constant damage can lead to eventual blindness. In general, eye pressure causes the damage to the nerve fibers. There are many risk factors that can lead to glaucoma like old eye injuries, family history, increased age, high blood pressure, and corticosteroid use. If you have one of these risk factors, then you should ask your ophthalmologist for a glaucoma assessment. This is also true if you notice blind spots, ghost images, increased sensitivity to light, wavy vision, difficulties focusing, and double vision. Once you make an appointment with your eye doctor, you will be asked to go through a variety of glaucoma tests. These exams may include the following. 

Corneal Thickness Test

One of the glaucoma tests you are likely to undergo involves the evaluation of the cornea. The cornea is the thin and clear membrane that covers the exterior of the eye. The test is called a pachymetry exam and a small and thin probe is set gently against the surface of the eye. The probe provides the eye doctor with a reading that indicates how thick the tissue is. This test is necessary to complete in conjunction with some of the other eye pressure tests, because cornea thickness can affect the outcome of the exams. Thankfully, the probe test is quick and painless.

Pressure Test

One of the most valuable tests completed during your glaucoma evaluation involves the tonometry or eye pressure exam. During the initial test, a warm puff of air will likely be used to place slight pressure against each of the eyes. Your ophthalmologist will look through a machine that shines a light on the cornea as the air is transmitted, and the eye doctor will look to see how the light changes or reflects as the puff hits the cornea. This change helps to determine pressure in the eye.

If an initial tonometry test has already been completed that indicates elevated eye pressure, then a more pinpointed tonometry test will be done. Your ophthalmologist will likely use drops to numb the eyes and a dye will be applied to the cornea. An orange tinted material will likely be used and your eye doctor will set the tonometry machine just against the surface of the eye. A lamp is used to shine light inside and pressure is evaluated. In some cases, a probe will be used in much the same way as it is with the pachymetry test and an automatic reading will be provided with the device.

Nerve Evaluation

If pressure tests indicate that there is elevated pressure within the eye and if you are already experiencing glaucoma symptoms, then an opthalmoscopy exam will be completed. The test allows your eye doctor to inspect the optic nerve for damage. Your pupils will need to be dilated for the test, so it may take longer to complete than some of the other tests. You also may need a ride home since your eyes may be too sensitive to drive afterwards. 

Once the pupils are dilated, a light will be shone in the eye either with a handheld magnification device or with a light seated on the ophthalmologist's head. The device or a separate handheld lens will be secured very close to the eye and the doctor will look through it to examine the back area where the optic nerve sits. The nerve tissues and the blood vessels are examined as you are asked to move your eyes around. If optic never damage is noted, then you may need a perimetry exam. This helps to map out your visual field so blind spots can be located.

Once all of the tests are completed, your ophthalmologist can inform you of the severity of your glaucoma issue and a treatment plan will be formed for you. Medications, eye drops, diet changes, and surgery are all things that may be included in the plan. For more information, look at sites like