Making a glaucoma diagnosis as early as possible is important so that it can be treated before irreversible blindness occurs. There are various diagnostic tests available, and many doctors use several in one appointment to ensure that if glaucoma is present, it is detected. A glaucoma diagnosis can be made using various tests that use different tools to examine the eye, such as tonometry, dilated eye examination, and pachymetry. A visual field test and an acuity test can also be performed, during which both the ability to see from a distance and the capacity to see clearly at all can be examined. Once a glaucoma diagnosis is made, there are a few tests to determine the type of this condition, such as angle-closure or open-angle glaucoma.
One of the most important tests is tonometry, which examines the pressure in the eye, as high intraocular pressure can be a sign of glaucoma. Typically, either numbing drops are put in the eye and a probe is placed on the eye's surface, or a machine is used to blow air into each eye. A dilated exam tests for optic nerve damage, requiring the doctor to peek through the pupil to the back of the eye using certain tools. This way, he can see any changes to the eye that might result in a glaucoma diagnosis. Additionally, the thickness of the corneas can be checked through a test called pachymetry, during which the eyes are numbed and the corneas are examined closely.
Just like a typical eye examination, a glaucoma diagnosis often requires that a standard vision test be given. The visual field test measures both central and peripheral vision in order to check for vision loss of any kind. Additionally, the visual acuity test may be given, which screens for how far away the patient can see clearly. Many patients are likely familiar with these types of screenings since they are often given during annual eye exams, as well.
Once a glaucoma diagnosis is made, it is time to determine which type it is. One example of a test for this purpose is called gonioscopy. This exam requires the doctor to place a lens on the eye in order to check the angle of the drainage, while tonography allows the doctor to determine how fast fluid drains out of each eye. These screenings can help distinguish between angle-closure glaucoma and the open-angle form, so they are usually only necessary after a basic glaucoma diagnosis has been made.
