Glaucoma Tests: Types, Purposes, Risks, and What to Expect

Explore comprehensive glaucoma testing: understand key test types, their purpose, potential risks, and why early detection is vital.

By Sneha Tete, Integrated MA, Certified Relationship Coach

Created on Sep 25, 2025

Explore comprehensive glaucoma testing: understand key test types, their purpose, potential risks, and why early detection is vital.

Glaucoma Testing: How It’s Done and Why It Matters

Glaucoma is a serious, progressive eye disease that can cause irreversible vision loss if not detected and treated early. Since the early stages of glaucoma often have no warning signs, regular eye exams and specific glaucoma tests are essential for early detection, ongoing monitoring, and prevention of permanent damage.

What Is Glaucoma?

Glaucoma refers to a group of eye conditions that lead to damage of the optic nerve—the critical link between your eyes and your brain. This damage is most frequently (but not always) associated with abnormally high pressure inside the eye, known as intraocular pressure (IOP). If left untreated, glaucoma can result in permanent vision loss, often starting with peripheral (side) vision and progressing to full blindness in severe cases.

Why Is Glaucoma Testing Important?

Many forms of glaucoma—particularly open-angle glaucoma, the most common type—advance silently with no symptoms until significant vision loss has occurred. Because lost vision cannot be restored, early detection through routine testing is critical for slowing or preventing further damage. Regular testing is also key for people who are already diagnosed with glaucoma, as it allows doctors to monitor progression and adjust treatment as necessary.

Early detection increases the chances of preserving sight with appropriate treatment.
People at higher risk (such as those over age 60, with a family history of glaucoma, or of African American descent) require especially vigilant screening.

Types of Glaucoma Tests

Diagnosing and managing glaucoma involves several specialized tests, often performed in combination. Here are the five main glaucoma tests:

1. Dilated Eye Exam (Ophthalmoscopy)

This test allows an ophthalmologist to examine the health of your optic nerve, which is vital for vision. After administering special drops to widen (dilate) your pupils, the doctor uses a magnifying lens with a bright light to get a detailed view of the optic nerve and any changes or damage that may be early signs of glaucoma.

Procedure: Eye drops cause pupil dilation; vision may be temporarily blurry afterward.
Purpose: Identifies optic nerve changes and damage typical of glaucoma.

2. Gonioscopy

Gonioscopy examines the angle where your cornea and iris meet. This angle controls the drainage of fluid from the eye—poor drainage can cause elevated intraocular pressure.

Procedure: Numbing eye drops are used; a special lens is gently placed on the eye to visualize the angle.
Purpose: Detects narrow or closed angles that may indicate angle-closure or open-angle glaucoma.

3. Pachymetry

This test measures the thickness of the cornea with a small device called a pachymeter.

Procedure: Eye is numbed; device briefly touches the cornea to measure thickness.
Purpose: Identifies thin corneas, which can increase glaucoma risk or affect eye pressure readings.

4. Perimetry (Visual Field Test)

Perimetry tests your entire field of vision, including side (peripheral) vision, to determine if glaucoma has affected your ability to see objects outside the direct line of sight.

Procedure: You’ll look straight ahead and respond when you see lights popping up in various parts of your visual field.
Purpose: Maps out vision loss patterns typical of glaucoma; important for ongoing monitoring.

5. Tonometry

Tonometry measures the pressure inside your eye (intraocular pressure or IOP). High IOP is a significant risk factor for glaucoma.

Procedure: Numbing eye drops are applied; a puff of air or gentle probe assesses eye pressure, often using a slit lamp for accuracy.
Purpose: Detects pressure higher than the normal range of 12 to 21 mm Hg, which may suggest glaucoma.

When Are Glaucoma Tests Needed?

Testing is crucial at multiple stages:

Routine screening: Especially important for people over 60, those with a family history, particular ethnic backgrounds (such as African Americans over age 40), or with risk factors like diabetes or high blood pressure.
Diagnosis: To confirm glaucoma in people with suspicious symptoms or risk factors.
Monitoring: For those already diagnosed, to track disease progression and treatment effectiveness.

Test Name	Main Purpose	What It Involves
Dilated Eye Exam	View optic nerve health	Pupil dilation, lens inspection
Gonioscopy	Examine drainage angle	Lens on eye, angle assessment
Pachymetry	Measure corneal thickness	Contact with cornea
Perimetry	Test visual field	Detects blind spots
Tonometry	Measure eye pressure	Puff of air or probe

Who Is at Risk for Glaucoma?

The following factors can increase your risk for developing glaucoma:

Age: Risk increases for people over 60.
Family History: Genetics play a significant role—glaucoma risk is higher if close relatives have it.
Race: African Americans, Hispanics, and Asians are at higher risk for certain types of glaucoma.
Personal Eye Health: Prior eye injuries, inflammation, or certain eye diseases increase risk.
Medical Conditions: Diabetes, hypertension, and some heart diseases can raise the risk.
Chronic Medication Use: Long-term use of corticosteroids and immunosuppressive medications can increase risk.

Are There Risks Involved with Glaucoma Testing?

Glaucoma tests are generally very safe. Most involve only mild, temporary discomfort:

Eye numbness: Temporary following numbing drops.
Pupil dilation: May cause light sensitivity and blurry vision for a few hours. Some people may want to arrange transportation home as a precaution.
No lasting harm: No significant health risks or long-term effects are associated with standard glaucoma testing procedures.

Interpreting Glaucoma Test Results

The outcome of glaucoma testing determines your diagnosis and guides treatment. Some key results and what they mean:

Eye pressure (IOP): A reading between 12–21 mm Hg is considered normal. Pressure above that range may indicate an increased risk of glaucoma, but elevated IOP alone does not confirm the diagnosis.
Visual field defects: Blind spots or reduced peripheral vision may show early or advancing glaucoma damage.
Optic nerve appearance: Changes in the optic nerve’s color or shape—such as cupping or thinning—can be early signs of glaucoma.
Corneal thickness: Thin corneas can mask high pressure and are a risk factor themselves.

Doctors often use results from several of these tests together to make or confirm a diagnosis.

How Often Should You Be Tested?

The frequency of glaucoma testing depends on your age, risk factors, and whether you already have glaucoma. General guidelines:

Adults under 40: Eye exam every 2–4 years
Ages 40–54: Every 1–3 years
Ages 55–64: Every 1–2 years
65 and older, or at high risk: Annually or as recommended by the ophthalmologist

Living with Glaucoma: The Importance of Regular Eye Exams

People with diagnosed glaucoma require ongoing monitoring to manage the condition and prevent vision loss. Routine tests check for changes in eye pressure, optic nerve health, and visual field performance. Losing vision from glaucoma is irreversible, so regular eye exams are the best defense.

Follow your doctor’s recommendations on testing frequency.
Notify your eye care provider of any changes in vision or eye symptoms.
Adhere strictly to prescribed treatment plans, including eye drops or other medications.

Frequently Asked Questions (FAQ)

What tests are used to diagnose glaucoma?

A comprehensive glaucoma diagnosis often involves a combination of tonometry (eye pressure measurement), dilated eye exam, gonioscopy, perimetry (visual field test), and pachymetry (corneal thickness measurement). Some clinicians may also use advanced optic nerve imaging.

Does glaucoma testing hurt?

Most glaucoma tests are painless or cause only short-lived, mild discomfort. Numbing drops help with any procedures involving contact with the eye. You may feel a brief sensation during a puff of air or when the tonometer touches the eye, but it is not usually painful.

How accurate are glaucoma tests?

No single test is perfectly accurate on its own. Doctors use results from several different tests to confirm a glaucoma diagnosis and assess risk. Advanced imaging, such as scanning laser polarimetry, can provide high accuracy in detecting optic nerve damage.

I have a family member with glaucoma—should I get tested?

Yes. A family history of glaucoma significantly increases your risk. Early, regular eye exams are important for early detection and prevention of vision loss.

What should I do if I experience eye pain or sudden vision changes?

Seek prompt medical attention. Acute glaucoma attacks can cause sudden pain, redness, blurred vision, and even nausea. This is a medical emergency and requires immediate treatment to prevent rapid, irreversible vision loss.

Summary and Takeaway

Glaucoma tests are essential tools for early detection, diagnosis, and ongoing management of a sight-threatening disease. The main tests—dilated eye exam, gonioscopy, pachymetry, perimetry, and tonometry—each play a crucial role in assessing your risk and protecting your vision. Early diagnosis through routine eye exams is the most effective strategy for preventing glaucoma-related blindness. If you are at risk, schedule a comprehensive eye examination with an ophthalmologist and follow all recommended care to protect your vision for life.

References

Author

Sneha TeteBeauty & Lifestyle Writer

Sneha is a relationships and lifestyle writer with a strong foundation in applied linguistics and certified training in relationship coaching. She brings over five years of writing experience to thebridalbox, crafting thoughtful, research-driven content that empowers readers to build healthier relationships, boost emotional well-being, and embrace holistic living.

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