Objective:To define the incidence,duration,and clinical associations of persistent localized submacular fluid after pars plana vitrectomy(PPV) retinal detachment surgery.Design:Observational cohort series.Participants:One hundred patients were identified and recruited into the study.Methods:Patients aged 18 years and older who had undergone PPV and gas as a primary procedure for rhegmatogenous retinal detachment and postoperative follow-up were recruited from February through August 2004.All patients underwent clinical examination,optical coherence tomography(OCT) scan of the macula,and retinal thickness analysis scan of the macula.Those patients in whom an abnormality was seen on OCT at 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.Demographic data,including detachment characteristics,were collected retrospectively from the patient case notes.Main Outcome Measures:The principle outcome measure was the presence of subretinal fluid(SRF) on OCT at 6 weeks after surgery.Other outcome measures included duration of persistent fluid and association with visual outcome and type and duration of detachment.Results:One hundred patients were recruited;15 of these had SRF on OCT performed at 6 weeks after surgery.Subretinal fluid was associated with significantly worse visual acuity(VA) at 6 weeks(P=0.033,Wilcoxon rank-sum) ;those with SRF had a median VA of 0.4,and those with no SRF had a median VA of 0.3.The fluid took a median of 5.5 months to resolve.Seven patients had combined PPV and scleral buckle surgery;none of these had fluid at 6 weeks.Conclusions:Optical coherence tomography is a useful noninvasive diagnostic method that can detect SRF not appreciated on clinical examination.Persistent SRF after PPV and gas surgery occurred in 15% of patients in this study and was still present in 53% of these at 6 months.The presence of SRF at 6 weeks after surgery was associated with a poorer visual outcome at this time point. Objective: To define the incidence, duration, and clinical associations of persistent localized submacular fluid after pars plana vitrectomy (PPV) retinal detachment surgery. Design: Observational cohort series. Participants: One hundred patients were identified and recruited into the study. Methods: Patients aged 18 years and older who had undergone PPV and gas as a primary procedure for rhegmatogenous retinal detachment and postoperative follow-up were recruited from February through August 2004. All patients underwent clinical examination, optical coherence tomography (OCT) scan of the macula, and retinal thickness analysis scan of the macula.Those patients in whom an abnormality was seen on OCT at 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. Demographic data, including detachment characteristics, wer e collected retrospectively from the patient case notes. Main Outcome Measures: The principle outcome measure was the presence of subretinal fluid (SRF) on OCT at 6 weeks after surgery. Orthopedic measures included duration of persistent fluid and association with visual outcome and type and duration of detachment. Results: One hundred patients were recruited; 15 of these had SRF on OCT performed at 6 weeks after surgery. Subretinal fluid was associated with significantly worse visual acuity (VA) at 6 weeks (P = 0.033, Wilcoxon rank-sum ); those with SRF had a median VA of 0.4, and those with no SRF had a median VA of 0.3. The fluid took a median of 5.5 months to resolve. Seven patients had combined PPV and scleral buckle surgery; none of these had fluid at 6 weeks. Conclusions: Optical coherence tomography is a useful noninvasive diagnostic method that can detect SRF not likely on clinical examination. Persistent SRF after PPV and gas surgery occurred in 15% of patients in this study and was stillpresent in 53% of these at 6 months. The presence of SRF at 6 weeks after surgery was associated with a poorer visual outcome at this time point.