Cystoid macular edema

What is cystoid macular edema?

The retina is a delicate, light-sensitive tissue that lines the back of your eye. The macula, at its centre, is essential for tasks that require fine detail. When the blood vessels in or near the retina leak fluid, it can accumulate in the macula in a distinctive pattern, forming multiple tiny, fluid-filled cyst-like spaces. This swelling is referred to as cystoid macular oedema.

Cystoid macular oedema is not a disease in itself but rather a reaction to another eye problem or event. It can occur after eye surgery, with certain retinal conditions, or as a result of inflammation or circulation problems in the eye.

Cystoid macular edema symptoms

The symptoms of cystoid macular oedema can vary depending on the severity and underlying cause, but may include:

• Blurred or hazy central vision
• Distortion; straight lines may appear bent or wavy
• Reduced ability to see fine detail
• Faded or washed-out colours
• A dark or empty spot in the centre of vision in more severe cases

Importantly, cystoid macular oedema does not cause pain. Some patients may not notice symptoms in the early stages, especially if only one eye is affected.

Cystoid macular edema causes

Cystoid macular oedema develops when the small blood vessels in the retina leak fluid into the macula. This leakage can be triggered by a range of underlying issues, including:

• Eye surgery: particularly cataract surgery (known as Irvine-Gass syndrome when it occurs after surgery)
• Retinal vein occlusion: a blockage in the veins that drain blood from the retina
• Uveitis: inflammation inside the eye
• Diabetic retinopathy: a complication of diabetes affecting retinal blood vessels
• Eye injury or trauma
• Certain medications, such as some used to treat glaucoma

Cystoid macular edema following cataract surgery

Cystoid macular edema is one of the more common complications after cataract surgery, though it remains relatively rare overall. Known as Irvine-Gass syndrome, this form of cystoid macular edema typically appears a few weeks after the operation, when the normal healing process triggers inflammation that causes fluid to leak into the macula.

Most post-cataract cystoid macular edema cases respond well to treatment, and vision often returns close to the pre-surgery level. Prompt recognition and treatment are important for the best recovery.

How serious is cystoid macular edema?

The seriousness of cystoid macular edema depends on its cause, severity, and how quickly it is treated. Mild cases, especially those detected early, may resolve with treatment and cause little long-term impact. However, if left untreated or if the underlying cause is ongoing, the swelling can damage the macula permanently, leading to lasting central vision loss.

Cystoid macular edema treatment

Treatment for cystoid macular edema aims to reduce swelling, address inflammation, and treat the underlying cause. Common approaches include:

• Anti-inflammatory eye drops such as non-steroidal anti-inflammatory drugs (NSAIDs) or corticosteroids
• Corticosteroid injections, delivered into or around the eye to reduce inflammation
• Anti-VEGF injections, used particularly when CMO is linked to abnormal blood vessel growth, such as after vein occlusion
• Treating the underlying condition, for example, controlling diabetes, reducing intraocular inflammation, or managing vein blockages

The choice of treatment depends on the cause and severity of the oedema. Many cases, particularly those after cataract surgery, respond well to targeted therapy.

Living with cystoid macular edema

While cystoid macular edema is being treated, small changes to your daily routine can help you make the most of your vision. Using brighter, well-positioned lighting for reading or hobbies can reduce eye strain, and holding books or devices at a slightly different distance may make details clearer. Magnifying glasses or smartphone apps can also be useful for reading small print.

It’s important to attend all follow-up appointments so your specialist can monitor the swelling and adjust treatment as needed. Keeping track of any changes in your sight, and letting your doctor know promptly, can make a real difference to your recovery.