Postoperative cystoid macular oedema is a complication of uneventful cataract surgery. Whereas improved surgical techniques have decreased the incidence of cystoid macular oedema, it remains a cause of unfavourable visual outcome following surgery. Fundus fluorescein angiography has been the 'gold standard' for diagnosing subclinical cystoid macular oedema; however, non-invasive cross-sectional imaging of the retina with optical coherence tomography may be equally effective at detecting the condition and offers the ability to quantify and repeat results over time.Prospective pre-post case series of patients undergoing routine phaco-emulsification surgery.Eighty consecutive patients (100 eyes) with cataracts and an age range of 40 to 90 years (mean 76.18).Macular thickness of participants was determined using time-domain optical coherence tomography preoperatively and after surgery at 1 day, 1 week, 4 weeks and 6 months. Optical coherence tomography was used to diagnose postoperative cystoid macular oedema.Presence of cysts at the macula, identified by optical coherence tomography, in addition to foveal and macular thickness (µm).Cystoid macular oedema was present in 5% of eyes. Macular thickness increased after surgery and central foveal thickness increased by almost 7% but returned to preoperative levels after 6 months. Findings also indicate that patients who developed postoperative cystoid macular oedema had significantly thicker central foveal thickness of approximately 5% compared with those that did not.Optical coherence tomography is a useful, non-invasive diagnostic tool in determining subclinical cystoid macular oedema in uncomplicated cataract surgery patients and detects the presence of retinal thickening and intra-retinal cysts very soon after surgery, thereby facilitating earlier diagnosis and treatment of postoperative cystoid macular oedema.