Glaucoma Diagnosis

Glaucoma is thought to affect more than two million people in the United States, most of them over the age of 50. The only way to combat glaucoma is through early diagnosis and treatment. Learn more about how glaucoma is diagnosed, including information about the glaucoma test and eye exam.

How Is Glaucoma Detected?

Open-angle glaucoma, the most common form of the disease, is often referred to as the "silent thief of sight" because it presents no physical symptoms until the first signs of vision loss. Only preventive glaucoma diagnosis and treatment can effectively preserve vision. This is why it is important to have annual eye exams that include a glaucoma test to check intraocular pressure. Early detection is the key to protecting your vision from damage caused by glaucoma. The Glaucoma Research Foundation recommends that you eyes should be tested at:

• Ages 35 and 40
• From age 40 to age 60 – every two years
• After age 60 – every year
• Anyone with high risk factors should be tested every year after age 35.

Glaucoma Exam and Test

Individuals at greatest risk for glaucoma should have their eye doctor perform a comprehensive eye exam and diagnostic glaucoma tests. If glaucoma tests identify the disease in its early stages, it can be managed before severe vision loss occurs. Regular glaucoma check-ups include two routine eye tests: tonometry and ophthalmoscopy. If the pressure in the eye is not in the normal range, or if the optic nerve looks unusual, then one or two special glaucoma tests will be done. These two tests are called gonioscopy and perimetry. The glaucoma test and eye exam includes the following:

Family History

The most common type of glaucoma, primary open angle glaucoma, is hereditary. If members of your immediate family have glaucoma, you are at a much higher risk than the rest of the population. Family history increases risk of glaucoma four to nine times.

Visual Acuity Test

Field of vision changes are one of the first symptoms to surface in glaucoma patients. By the time central vision is affected, glaucoma is already too far advanced with almost all peripheral vision permanently lost. A visual acuity test measures a patient’s ability to see far away or up close. For this test, you may be asked to read from an eye chart. The visual acuity test uses an eye chart with letters and images to measure vision ability at various distances.

Intraocular Pressure Check (Tonometry)

The tonometry test measures the eye’s intraocular pressure (IOP). The test is used in the detection and diagnosis of glaucoma. Usually drops are used to numb the eye before the doctor or technician uses a special device to measure the eye’s pressure. The tonometry test takes only minutes to perform and does not cause any eye pain.

Retinal and Optic Nerve Exam (Ophthalmoscopy)

Ophthalmoscopy is used to examine the inside of the eye, focusing on the retina and optic nerve. In a darkened room, the physician will dilate the pupils before magnifying the patient’s eye using an ophthalmoscope (an instrument with a small light on the end). This allows the physician to look at the shape and color of the optic nerve. If this test reveals an optic nerve that looks unusual, additional glaucoma tests (gonioscopy and perimetry) will be done.

Drainage Angle Inspection (Gonioscopy)

Gonioscopy is a painless eye test that determines whether the area where fluid drains out of your eye (the drainage angle) is open or closed. It is often done during a routine eye examination, depending on your age and whether or not you are at high risk for developing glaucoma. Although the causes of glaucoma are not well understood, if the drainage angle becomes damaged, blocked, or clogged, pressure may increase inside the eye.

Evaluation of the Visual Field (Perimetry)

A perimetry glaucoma test measures all areas of your vision, including your peripheral vision. At the end of the test, a printout shows if there are any areas of vision loss. Loss of peripheral vision is often an early sign of glaucoma. Early detection is key in successful glaucoma diagnosis and treatment.

Find a Glaucoma Specialist through DocShop

If you would like more information about glaucoma diagnosis and treatment, DocShop can provide you with a list of eye care professionals in your area that can perform the glaucoma test and answer any additional questions you may have. Find a glaucoma specialist near you.