When diagnosing glaucoma, a healthcare provider will typically do a comprehensive eye exam that includes a visual acuity test, visual field test, and dilated eye exam. Although many people are familiar with the common "air puff" test conducted at regular eye exams, most are not aware that this test alone cannot detect glaucoma.
Many people may know of the "air puff" test or other tests used to measure eye pressure during an eye examination. However, this test alone cannot detect glaucoma; while elevated eye pressure means that you are at risk for developing glaucoma, it does not necessarily mean that you have it (see Glaucoma and Eye Pressure). A person has glaucoma only if the optic nerve is damaged. If you have increased eye pressure but no damage to the optic nerve, you do not have glaucoma.
Most often, in order to diagnose glaucoma, your doctor will ask you a number of questions (medical history) and perform a comprehensive eye exam.
A glaucoma diagnosis is made through a comprehensive eye exam that includes:
- Visual acuity test. This eye chart test measures how well you see at various distances.
- Visual field test. A visual field test measures your side (peripheral) vision. It helps your eye care professional tell if you have lost side vision, a sign of glaucoma.
- Dilated eye exam. For this eye exam, drops are placed in your eyes to widen, or dilate, the pupils. Your eye care professional uses a special magnifying lens to examine your retina and optic nerve for signs of damage and other eye problems. After the exam, your close-up vision may remain blurred for several hours.
- Tonometry. A tonometry is an instrument that measures the pressure inside the eye. Numbing drops may be applied to your eye for this test.
- Pachymetry. For a pachymetry, a numbing drop is applied to your eye. Your eye care professional uses an ultrasonic wave instrument to measure the thickness of your cornea.