Objective: To define the incidence, pattern, duration, and clinical consequences of persistent localized submacular fluid after scleral buckle surgery for retinal detachment (RD). Design: Prospective observational cohort series. Participants: Ninety-eight patients were identified and recruited to the study. Methods: Patients aged >= 18 years undergoing scleral buckle surgery for uncomplicated primary RD over an 18-month period were recruited. All patients underwent clinical examination and optical coherence tomography (OCT) scan of the macula preoperatively and at 6 weeks postoperatively. Those patients who had an abnormality on OCT 6 weeks after surgery underwent follow-up with repeat of the study investigations at 3, 6, 9, 12, and 18 months after surgery until the abnormality resolved. If no abnormality was seen at the 6-week examination, no further investigation was undertaken. Main Outcome Measure: Presence of submacular fluid on OCT 6 weeks after surgery. Other outcome measures were duration of persistent fluid and associations with poor visual outcome, type, or duration of detachment. Results: Of the 98 patients recruited into the study, 54 (55%) had subretinal fluid (SRF) on OCT 6 weeks after surgery. We identified 3 patterns of submacular fluid: confluent fluid, a single discrete bleb of fluid, and multiple blebs of fluid. Fluid was associated with delayed visual recovery. Of those with SRF, 78% had persistent fluid at 6 months; resolution of fluid took a median of 10 months and was associated with an improvement in vision. Conclusions: Optical coherence tomography is a useful noninvasive diagnostic method that can detect SRF not seen on clinical examination. Persistent SRF 6 weeks after scleral buckle surgery of patients, may persist for many months, and can cause delayed visual recovery.