---
title: What Is Cystoid Macular Oedema After Cataract Surgery?
description: "Cystoid macular oedema (CMO) is fluid build-up in the central retina after cataract or lens replacement surgery. Tiny blood vessels around the fovea become leaky, so fluid collects in cyst-like spaces within the retinal layers.¹ Patients may notice blurred or…"
url: "https://bluefinvision.com/knowledge-base/topics/conditions-diseases/what-is-cystoid-macular-oedema-after-cataract-surgery/"
updated: "2026-02-18"
category: "Conditions & Diseases"
---

# What Is Cystoid Macular Oedema After Cataract Surgery?

Cystoid macular oedema (CMO) is fluid build-up in the central retina after cataract or lens replacement surgery. Tiny blood vessels around the fovea become leaky, so fluid collects in cyst-like spaces within the retinal layers.¹

Patients may notice blurred or hazy central vision, reduced contrast or a disappointing "dip" in vision several weeks after an apparently smooth operation. Optical coherence tomography (OCT) shows characteristic pockets of fluid in the outer plexiform and inner nuclear layers.²

Many cases are mild and resolve with treatment, but untreated oedema can delay recovery and occasionally limit best-corrected vision.¹ CMO is usually driven by an inflammatory cascade rather than by "rough" surgical technique.

Understanding this mechanism allows us to design drop regimens and OCT follow-up that reduce the risk of clinically significant oedema and detect changes before they harm vision.

**References**

1. Lobo C. Pseudophakic cystoid macular edema. Ophthalmologica. 2012;227(2):61-67.
2. Gharbiya M, Grandinetti F, Scavella V, et al. Correlation between OCT measurement and fluorescein angiography in CMO. Invest Ophthalmol Vis Sci. 2007;48(9):3763-3770.

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