MACULAR STRUCTURE AND FUNCTION IN RETINAL DETACHMENT COMPLICATED BY PROLIFERATIVE VITREORETINOPATHY

INTRODUCTION: Macular structural changes after surgery for rhegmatogenous retinal detachment (RRD) complicated by proliferative vitreoretinopathy (PVR) remain poorly characterised. The aim of this study was to evaluate longitudinal macular structural changes on optical coherence tomography (OCT) and their relationship to visual function over 12 months in eyes undergoing pars plana vitrectomy (PPV) with silicone oil tamponade for PVR-related RRD. METHODS: Post-hoc analysis from a phase IIIb, single-centre, participant-masked, prospective, randomised controlled trial of slow-release dexamethasone in PVR-related RRD conducted at Moorfields Eye Hospital. One hundred and thirty-nine (139) eyes of 139 patients undergoing PPV with silicone oil tamponade for RRD with confirmed PVR-C were included. Spectral-domain OCT imaging and best-corrected visual acuity (BCVA, LogMAR) were obtained preoperatively and at 10 days, 6 months, and 12 months postoperatively. Retinal-layer thicknesses were obtained by manual segmentation and 13 qualitative biomarkers were graded. Univariable regression and Firth penalised multivariable logistic regression were used to identify early structural predictors of 12-month BCVA. RESULTS: Central retinal thickness (CRT) increased significantly from 314.9 µm at 10 days to 370.9 µm at 12 months (p < 0.0001). The outer plexiform layer and outer nuclear layer showed dynamic changes over time. The proportion of eyes with epiretinal membrane (ERM) rose from 22.1% at 10 days to 41.2% at 6 months (p=0.001) and 49.6% at 12 months (p=0.011 versus 6 months), and cystoid macular oedema (CMO) increased from 20.7% to 52.2% (p<0.0001) and 62.6% (p = 0.029). Mean BCVA improved from 1.68 LogMAR preoperatively to 1.06 LogMAR at 10 days (p < 0.0001), with no significant further change to 0.92 LogMAR at 12 months. In univariable analysis, retinal pigment epithelium (RPE) thickness, outer retinal layer thickness, gross full-thickness retinal disruption, disrupted ellipsoid and external limiting membrane, absence of a foveal bulge, subretinal PVR and persistent subretinal macular fluid at 10 days were associated with poorer 12-month BCVA (all p < 0.05). In the multivariable model, 10-day BCVA (adjusted odds ratio [aOR] 3.52, 95% CI 1.31-11.2) and gross full-thickness retinal disruption (aOR 10.51, 95% CI 1.16-1391) remained independently associated with moderate visual impairment at 12 months (BCVA worse than 6/38; LogMAR > 0.80), with an area under the receiver operating characteristic curve of 0.71. CONCLUSIONS: Macular structural changes after surgery for PVR-related RRD reflect extensive cellular remodelling with progressive development of ERM and CMO. Early (10-day) postoperative OCT findings are associated with 12-month visual outcome and may help inform prognosis in PVR-related RRD.