Glaucoma Tests

Glaucoma tests are eye examinations used to screen for and diagnose a group of eye diseases that can damage the optic nerve, potentially leading to vision loss and blindness.

Overview

Glaucoma is a group of eye diseases that damage the optic nerve, the nerve that connects your eyes to your brain. While the exact cause of most common types of glaucoma is unknown, high fluid pressure in the eye is a known risk factor. Eyes produce fluid that nourishes internal tissues and drains through a specific system. If this system becomes clogged or blocked, fluid backs up, increasing pressure and potentially damaging the optic nerve.

Types of Glaucoma

• Open-angle glaucoma: The most common type. The drainage canals are open, but clogs develop deeper inside the system, slowing fluid drainage. It typically affects both eyes, often with no symptoms in early stages. Without treatment, peripheral vision is usually lost first.
• Closed-angle glaucoma: An uncommon type where the iris covers the drainage canals.
  • Acute closed-angle glaucoma: A medical emergency where eye pressure increases suddenly, causing pain, blurry vision, and potential blindness within days.
  • Chronic closed-angle glaucoma: Develops slowly over time. Symptoms may include eye discomfort, blurry vision, redness, or headaches, which often improve with sleep.

Why Testing is Necessary

Because glaucoma often lacks early symptoms, testing is vital for protection. Risk factors include:

• Being over age 60 (especially Hispanic/Latino Americans).
• Being an African American over age 40.
• Being an Asian American (higher risk for normal-pressure glaucoma).
• Having a family history of the disease.
• Having medical conditions like diabetes or high blood pressure.

Seek immediate testing if you experience symptoms of acute closed-angle glaucoma, such as severe eye pain, blurry vision, red eyes, colored halos around lights, nausea, or headaches.

What Happens During a Glaucoma Test

Tests are performed by an ophthalmologist or optometrist during a comprehensive eye exam and may include:

• Tonometry tests: Measure eye pressure via an air-puff test or applanation tonometry (using a slit lamp or handheld device).
• Pachymetry test: Measures the thickness of the cornea to provide context for eye-pressure readings.
• Ophthalmoscopy (dilated eye exam): Uses eye drops to widen pupils, allowing the specialist to inspect the optic nerve for damage.
• Visual field test (perimetry): Measures your peripheral vision.
• Gonioscopy: Uses a special contact lens to examine the eye's drainage system.
• Optical coherence tomography (OCT): Creates images of the back of the eye to show optic nerve damage.

Results and Management

If diagnosed, treatment cannot restore lost vision but can prevent further damage. Management may include medicines to lower eye pressure, laser therapy, or surgery to improve fluid drainage. Regular follow-up testing is necessary to monitor the condition and treatment efficacy.