A perimetry test (also known as a visual field test) is an eye examination used to measure the full horizontal and vertical range of what you can see peripherally, while keeping your eyes focused straight ahead. It’s commonly used by eye care professionals to detect blind spots (scotomas) or vision loss in different areas of your visual field.
🔍 Purpose of a Perimetry Test:
- Detect glaucoma (a major use of the test)
- Diagnose or monitor:
- Retinal diseases
- Optic nerve damage
- Brain injuries or tumors
- Stroke-related vision problems
- Neurological disorders like multiple sclerosis
🧪 Types of Perimetry Tests:
- Static Perimetry (Automated Perimetry)
- You sit in front of a dome and press a button when you see lights flash.
- Most common machine: Humphrey Field Analyzer.
- Kinetic Perimetry
- Moving lights are used instead of static ones.
- Often done with a device called a Goldmann perimeter.
- Confrontation Visual Field Test
- A simple manual test done by a doctor, using fingers in different parts of your field of view.
- Less precise, used for quick screening.
🧠 What It Can Reveal:
- Glaucoma: Gradual loss of peripheral vision
- Stroke: Specific areas of field loss
- Pituitary tumors: Tunnel vision or bitemporal hemianopia
- Retinal diseases: Localized scotomas
⏱️ How Long Does It Take?
- Usually 10–30 minutes, depending on the type and extent of the test.
❗ Important Notes:
- It’s non-invasive and painless.
- It requires your attention and concentration.
- Early detection of vision changes can prevent irreversible vision loss, especially in conditions like glaucoma.