---
title: What is epithelial thickness mapping?
description: "Epithelial thickness mapping measures the thickness of the cornea's outer skin layer across the entire surface. ## How epithelial mapping is performed Using advanced scans such as OCT or specialised topography, the device builds a colour map. This shows where…"
url: "https://bluefinvision.com/knowledge-base/topics/diagnostics-testing/what-is-epithelial-thickness-mapping/"
updated: "2025-12-31"
category: "Diagnostics & Testing"
---

# What is epithelial thickness mapping?

Epithelial thickness mapping measures the thickness of the cornea's outer skin layer across the entire surface.

## How epithelial mapping is performed

Using advanced scans such as OCT or specialised topography, the device builds a colour map. This shows where the epithelium is thinner or thicker, often in great detail.

- The scan is painless and takes only a few seconds per eye
- No contact is made with the eye and usually no drops are needed
- You simply look at a target while the machine captures images
- The test can be repeated safely whenever needed

## Why epithelial mapping is useful

Changes in thickness can reveal early keratoconus or other corneal problems. It also guides planning for laser eye surgery and helps monitor healing after procedures.

- Identifies subtle irregularities not visible on standard examination
- Supports decisions about suitability and safety of refractive surgery
- Helps explain unexplained blur or ghosting of images
- Allows precise follow-up of corneal disease progression