Improved Outcomes with Heavy Silicone Oil in Complex Primary Retinal Detachment: A Large Multicenter Matched Cohort Study

PURPOSE:To establish whether Densiron® 68, a heavier-than-water endotamponade agent, is an effective alternative to conventional light silicone oil in primary rhegmatogenous retinal detachment surgery for eyes with inferior breaks in the detached retina and severe proliferative vitreoretinopathy. DESIGN:Cohort study of routinely collected data from the European Society of Retina Specialists (EURETINA) and British and Eire Association of Vitreoretinal Surgeons (BEAVRS) vitreoretinal database between 2015 and 2022. PARTICIPANTS:All consecutive eyes that underwent primary rhegmatogenous retinal detachment surgery using either Densiron® 68 or light silicone oil as an internal tamponade agent. METHODS:To minimize confounding bias, we undertook 2:1 nearest neighbor matching on inferior breaks, large inferior rhegmatogenous retinal detachments, proliferative vitreoretinopathy, and, for visual analyses, baseline visual acuity between treatment groups. We fit regression models including prognostically relevant covariates, treatment-covariate interactions, and matching weights. We used g-computation with cluster-robust methods to estimate marginal effects. For nonlinear models, we calculated confidence intervals using bias-corrected cluster bootstrapping with 9 999 replications. MAIN OUTCOME MEASURES:Presence of a fully attached retina and visual acuity at least two months after oil removal. RESULTS:Of 1061 eyes enrolled, 426 and 239 were included in our matched samples for anatomical and visual outcome analyses, respectively. The primary success rate was higher in the Densiron® 68 group (113 of 142; 80%) compared to the light silicone oil group (180 of 284; 63%), with an adjusted odds ratio of 1.90 (95% CI 1.63 to 2.23, P < 0.001). We also observed a significant improvement favoring Densiron® 68 of -0.26 logMAR in postoperative visual acuity between the two groups (95% CI -0.43 to -0.10, P = 0.002). The anatomical benefit of using Densiron® 68 in eyes with inferior retinal breaks and large detachments was more pronounced among eyes with proliferative vitreoretinopathy Grade C. We found no evidence of visual effect moderation by anatomical outcome or foveal attachment. CONCLUSIONS:Densiron achieved higher anatomical success rates and improved visual outcomes compared to conventional light silicone oil in eyes with inferior retinal pathology and severe proliferative vitreoretinopathy.