# What is a Visual Field Test?

Source page: https://www.kudretgozistanbul.com/en/blog/eye-diseases/what-is-a-visual-field-test

**Author:** Kudret Eye İstanbul | **Medical Approval:** Op. Dr. Mehmet Ali Özdil | **Date:** 2026-09-16

> **Summary:** A visual field test (perimetry) measures peripheral vision: how far you can see above, below and to the sides while looking straight ahead, and how sensitive each part of the field is. It is painless, needs no preparation, and is key to detecting and following glaucoma and other conditions of the eye, optic nerve and brain.

## Quick Facts
- **Other name:** Perimetry
- **Duration:** Generally ten minutes
- **Pain / anaesthesia:** Painless, no anaesthesia, no medication or surgery
- **Preparation:** None needed
- **Side effects:** None during or after the test

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## What Does It Measure?
- How sensitive the eye is in the different parts of the visual field
- How far the eye sees to the right, left, above and below while looking straight ahead

Vision is sharpest at the centre; objects further from the centre are seen less clearly, and far enough to the side they leave the field of vision. The area seen outside the centre is peripheral vision.

## Why It Is Done
It is a routine part of eye examinations and allows earlier detection and follow-up of conditions that damage vision gradually. People with glaucoma may feel their vision is fine while the test reveals gaps in their peripheral vision.

It also shows what is happening in the visual pathway:
- **Retina:** converts light into electrical signals and passes them to the optic nerve.
- **Optic nerves:** carry the signals to the brain.
- **Brain:** processes the signals into an image.

A problem anywhere in this system changes the visual field; result patterns help identify the condition and its degree, and the test is repeated regularly for follow-up.

Conditions detected and followed with the test:
- Scotoma (blind spot)
- Glaucoma
- Macular degeneration
- Graves' disease
- Pituitary gland disorders
- Multiple sclerosis (MS)

## How It Is Done
You focus on a central point and respond to what you see. Simple methods:
- **Confrontation visual field:** the examiner sits about a metre away, stretches the arms out to the sides and moves them; you say when you notice the movement.
- **Amsler grid:** you look at a point at the centre of a square grid and report areas where lines look blurred, broken or distorted. It measures only the central visual field.

## Types of Perimetry
- **Static perimetry:** you look into a bowl-shaped device and press a button when you see a light. Octopus and Humphrey are among the most widely used.
- **Kinetic perimetry:** the examiner moves an object and you say when you see it; the Goldmann test is generally used.

In device tests the head stays still, there is always a central target, and points of light assess sensitivity for the most accurate result.