Cystoid macular oedema is the name given to a condition in which fluid accumulates within the substance of the macula, the specialised area of retina responsible for high quality vision. It is most commonly observed after cataract surgery when it occurs in about 1 in 200 cases. Although more common after complicated cataract surgery, it is mostly seen after uneventful straightforward surgery. For a few days after surgery, the patient will describe excellent vision, but this then starts to deteriorate, especially for reading. On the Snellen Visual Acuity chart, between 1 and 6 lines may be lost, the average being about 2 lines. Fortunately, the vision usually improves within 2 to 3 months. A combination of drops, such as Pred Forte and Acular, may help speed this up. If no improvmement is seen, injections of steroid either around the eye (sub-Tenons injection) or into the eye (intravitreal injection) may be used. Unfortunately, a few cases prove resistant to all intervention.
What is cystoid macular oedema?
The terms translates as swelling of the retina and on ocular coherence tomography, cystic spaces and retinal thickening can be seen in the retina. Unfortunately, it occurs in that part of retina concerned with reading, wathcing television and recognising faces, namely the macula.
Who gets cystoid macular oedema?
Cystoid macular oedema occurs in 1% patients are cataract surgery. The incidence increases to about 5% when surgery has been complicated by breakage of the posterior capsule supporting the lens. Infrequently, it may occur after other surgery such as vitrectomy.
When does it occur?
Usually it occurs after entirely uneventful cataract surgery. Patients will have good vision immediately after their surgery, but between 3 days and 4 weeks will notice that their central vision has deteriorated. On the visual acuity chart, the vision usually deteriorates by between 1 and 4 lines.
Is it treatable?
98% of the time, the vision improves over a period of between 3 and 12 months, with most patients responding by 3 months. We believe we speed up resolution by using a combination of steroid drops (Pred Forte x 4/day) and non-steroidal anti-inflammatory drops (Acular x 4/day) over a period of up to 3 months. If the vision doesn’t improve in this time, we would suggest a Sub-Tenons injection of long-acting steroid (Triamcinolone) and as a last resort, an intra-vitreal injection of Triamcinolone. The latter is very effective in most patients, but there unfortunately, one or two patients who prove to be resistant to all intervention and permanently lose some degree of vision with this condition.