---
title: "What is gonioscopy-assisted transluminal trabeculotomy (GATT)?"
description: "Gonioscopy-assisted transluminal trabeculotomy GATT is a minimally invasive glaucoma surgery that opens the eye's drainage canal 360 degrees from inside. ## How GATT is performed Under gonioscopic view, a microcatheter or suture is threaded through Schlemm's canal around the eye.…"
url: "https://bluefinvision.com/knowledge-base/topics/treatments-procedures/what-is-gonioscopy-assisted-transluminal-trabeculotomy-gatt/"
updated: "2025-12-31"
category: "Treatments & Procedures"
---

# What is gonioscopy-assisted transluminal trabeculotomy (GATT)?

Gonioscopy-assisted transluminal trabeculotomy GATT is a minimally invasive glaucoma surgery that opens the eye's drainage canal 360 degrees from inside.

## How GATT is performed

Under gonioscopic view, a microcatheter or suture is threaded through Schlemm's canal around the eye. The thread is then pulled through to cut the trabecular meshwork circumferentially.

- Creates a full-circle trabeculotomy to improve aqueous outflow
- Performed through a small incision without external filtering bleb
- Suitable for various types of open-angle glaucoma
- Can be combined with cataract surgery

## Benefits and considerations

GATT can achieve significant pressure drops while preserving conjunctiva for future procedures. Early postoperative bleeding inside the eye is common but usually settles.

- Recovery is often quicker than traditional trabeculectomy
- Some patients still require medication after surgery
- Not ideal for eyes with heavily scarred angles or neovascularisation
- Long-term results depend on individual anatomy and disease severity