---
title: What is tonometry?
description: "Tonometry is the measurement of intraocular pressure (IOP), one of the main risk factors for glaucoma. Different instruments and techniques can be used to obtain this value. ## Techniques Goldmann applanation tonometry estimates pressure by flattening a small area of…"
url: "https://bluefinvision.com/knowledge-base/topics/diagnostics-testing/what-is-tonometry/"
updated: "2026-01-03"
category: "Diagnostics & Testing"
---

# What is tonometry?

Tonometry is the measurement of intraocular pressure (IOP), one of the main risk factors for glaucoma. Different instruments and techniques can be used to obtain this value.

## Techniques

Goldmann applanation tonometry estimates pressure by flattening a small area of cornea, while non-contact methods use an air puff. Handheld devices are useful when the standard slit-lamp approach is not feasible.

- Corneal thickness and biomechanics influence measured IOP
- Single readings are less informative than a series over time
- High or fluctuating IOP increases the chance of optic nerve damage
- Tonometry is interpreted alongside nerve appearance and visual fields