Glaucoma Tests
Reviewed
Also called: Tonometry, Ophthalmoscopy, Visual Field Test, Perimetry, Gonioscopy, Pachymetry
Glaucoma tests are a group of eye exams that help diagnose glaucoma, a condition that can damage the optic nerve and lead to vision loss. These tests measure eye pressure, examine the optic nerve, check peripheral vision, and assess the eye's drainage system.
Specimen: Not applicable
Urgent safety information
If you have symptoms of acute closed-angle glaucoma, such as sudden severe eye pain, blurry vision, red eyes, colored halos around lights, nausea, vomiting, or headache, seek emergency care immediately. This is a medical emergency that can cause blindness in a few days without prompt treatment.
Why this test may be ordered
- To screen for glaucoma before symptoms appear
- To diagnose glaucoma if you have symptoms or risk factors
- To monitor glaucoma and check if treatment is working
Preparation and collection
If you wear glasses or contact lenses, bring them with you. Bring sunglasses to wear after the exam in case your eyes are sensitive to light. Also, plan to have someone take you home because your vision may be blurry after dilation.
Glaucoma tests are done as part of a comprehensive eye exam. Your eye care specialist may perform several tests: an air-puff test or applanation tonometry to measure eye pressure, a pachymetry test to measure corneal thickness, a dilated eye exam to look at your optic nerve, a visual field test to check side vision, and a gonioscopy to examine the eye's drainage canals. Some specialists may also use optical coherence tomography (OCT) to image the optic nerve.
According to MedlinePlus, there is no risk to having glaucoma testing. Some tests may feel a bit uncomfortable. If your eyes are dilated, you may have blurry vision and light sensitivity for a few hours.
Understanding results
Your eye care specialist will interpret the results of your glaucoma tests. The following are general patterns; your specialist will provide specific information based on your individual results.
- Screen-negative (normal eye pressure): Your eye pressure measured within a normal range during this quick screening test. This suggests a lower likelihood of glaucoma, but it does not rule out the disease. Limitation: The air-puff test is a screening tool and may not be as accurate as other tonometry methods. A normal result does not guarantee you do not have glaucoma, as some types occur with normal eye pressure. Next step: Your eye care specialist will consider your overall risk and may recommend regular screening based on your age and risk factors.
- Screen-positive (high eye pressure): Your eye pressure measured higher than normal during this screening test. This indicates a higher likelihood of glaucoma or risk for developing it. Limitation: The air-puff test is a screening tool and may have false positives. High eye pressure does not always mean you have glaucoma, and some people with glaucoma have normal pressure. Next step: Your eye care specialist will perform more accurate eye-pressure tests (such as applanation tonometry) and other glaucoma tests to confirm the diagnosis.
- No signs of glaucoma: Your eye pressure, optic nerve appearance, and peripheral vision are within normal limits. This suggests a lower likelihood of glaucoma. Limitation: Some early glaucoma may not be detected by these tests. Regular follow-up is important, especially if you have risk factors. Next step: Continue with routine eye exams as recommended by your eye care specialist.
- Signs of glaucoma or high risk: Your tests show elevated eye pressure, optic nerve damage, or visual field loss that may indicate glaucoma or a high risk of developing it. Limitation: These findings do not confirm a diagnosis on their own; your eye care specialist will consider all results together. Some conditions can mimic glaucoma. Next step: Your eye care specialist will discuss treatment options to lower eye pressure and prevent further vision loss. You may be referred to an ophthalmologist for further evaluation and treatment.
- Screening tests like the air-puff test may be less accurate than other methods and can give false-positive or false-negative results.
- Normal test results do not completely rule out glaucoma, especially normal-tension glaucoma.
- Abnormal test results do not always mean you have glaucoma; other eye conditions can cause similar findings.
- After dilation, you may have blurry vision and light sensitivity for a few hours, which can affect daily activities.
What to do next
If your tests suggest glaucoma, your eye care specialist will recommend a treatment plan to lower eye pressure and prevent vision loss. Treatment may include medicated eye drops, laser therapy, or surgery. Regular follow-up tests will be needed to monitor your condition and treatment effectiveness. If an optometrist performed the exam, you may be referred to an ophthalmologist for further care.
- What is my risk for developing glaucoma based on my age, race, and family history?
- How often should I have glaucoma tests?
- What do my specific test results mean for my eye health?
- What are the treatment options if I am diagnosed with glaucoma?
- What symptoms should I watch for that would require immediate medical attention?