Glaucoma Evaluations at NorthShore

Early detection of glaucoma can be done through regular vision exams. There are five tests that can be done to diagnose glaucoma: tonometry, ophthalmoscopy, perimetry, gonioscopy, and pachymetry.

Tonometry measures the pressure in your eyes. Eye drops are used to numb your eyes during this test, then a provider measures the inner pressure of your eye. Pressure is applied to your eye using a small puff of air. The normal range for pressure in your eye is 12-22 mm Hg, and those with a higher eye pressure than 22 mm Hg might be diagnosed with glaucoma.

Ophthalmoscopy allows your provider to examine the optic nerve. During this exam, eye drops are used to dilate your pupil so that your provider can see the optic nerve. Your provider can see into your eye with a small light. If the provider sees that the nerve looks suspicious, they may order either a perimetry or gonioscopy test.

Perimetry is a test that allows the provider to see your complete field of vision. During the exam, you will be asked to look ahead and let your provider know when you see a light pass your peripheral vision.

Gonioscopy helps determine if the angle where your cornea and iris meet is wide and open or narrow and closed. Eye drops are used during the exam to numb your eye, and then a contact lens with a mirror is put over your eye. The provider can use the lens to see the angle and make a diagnosis.

Pachymetry is an exam done to measure how thick your cornea is. With this test, your provider can determine the pressure in your eyes. This test takes only a few minutes to complete for both eyes.