---
title: Cystoid macular oedema (CMO)
description: "[Cystoid macular oedema is a particular pattern of swelling in the central retina](https://bluefinvision.com/blog/what-is-cystoid-macular-oedema/). Fluid collects in small cyst-like spaces, causing blurred and sometimes distorted central vision. ## Why CMO develops CMO can arise after surgery, inflammation, or retinal vein occlusion.…"
url: "https://bluefinvision.com/knowledge-base/topics/conditions-diseases/cystoid-macular-oedema-cmo/"
updated: "2026-01-22"
category: "Conditions & Diseases"
---

# Cystoid macular oedema (CMO)

[Cystoid macular oedema is a particular pattern of swelling in the central retina](https://bluefinvision.com/blog/what-is-cystoid-macular-oedema/). Fluid collects in small cyst-like spaces, causing blurred and sometimes distorted central vision.

## Why CMO develops

CMO can arise after surgery, inflammation, or retinal vein occlusion. Understanding the trigger helps guide tailored treatment.

- It commonly occurs after cataract surgery in susceptible eyes.
- Uveitis and diabetic retinopathy are other frequent causes.
- Patients notice difficulty reading, driving, or recognising faces.
- OCT imaging clearly shows the cystic spaces in the macula.
- Both eyes may be affected, particularly in inflammatory disease.

## Treatment and monitoring

The aim is to reduce fluid and protect long-term macular function. Many cases respond well to modern therapies.

- Anti-inflammatory drops or tablets are often used after surgery-related CMO.
- Steroid or anti-VEGF injections treat more persistent swelling.
- Controlling underlying inflammation is essential in uveitis-related CMO.
- Regular OCT scans track response and guide repeat treatments.
- Low-vision aids may help if some blur remains.