Evaluation of Subretinal Fluid Drainage Techniques During Pars Plana Vitrectomy for Primary Rhegmatogenous Retinal Detachment-ELLIPSOID Study

This was a retrospective, consecutive, interventional, comparative clinical study looking at 300 consecutive patients (300 eyes) with primary macula-off rhegmatogenous retinal detachments (RRD). The study compared RRD drainage techniques and their final outcomes. The primary outcomes of this study were the visual acuity and outer retinal integrity following 23g RRD repair with drainage from peripheral retinal breaks (PRB), posterior retinotomy (PR), or perfluorocarbon liquid (PFCL).

There were 100 patients included in each of the three drainage groups. Visual acuity and spectral domain optical coherence tomography (SD-OCT) were performed preoperatively and performed at 3, 6, and 12 months postoperatively. Specifically on OCT, the discontinuity of the external limiting membrane, ellipsoid zone, and interdigitation zone were noted.

Baseline characteristics amongst the three groups were similar in regards to age, gender, time to presentation, lens status, size of detachment, and preoperative vision. There were no differences between gas tamponade used, amount of laser used, or postoperative complications between the groups.

In regards to single surgery success for retinal reattachment, the rates were 86% in the PRB group, 85% in the PR group, and 83% in the PFCL group (P=.9). Mean visual acuity at 1 year was greater with PRB and PR compared with PFCL (P=.002). There were discontinuities in the external limiting membrane in 26% of the PRB group, 24% in the PR group, and 44% in the PFCL group (P=.001). There were discontinuities in the ellipsoid zone in 29% of the PRB group, 31% of the PR group, and 49% of the PFCL group (P<.001). There were discontinuities in the interdigitation zone in 43% of the PRB group, 39% of the PR group, and 56% of the PFCL group (P=.004). There was cystoid macular edema (CME) noted in 28% of the PRB group, 39% of the PR group, and 46% of the PFCL group (P=.003). Epiretinal membrane (ERM) was noted in 64% of the PRB group, 90% of PR group, and 61% of PFCL group (P<.001).

In summary, the different drainage techniques showed different outcomes in regards to visual acuity, outer retinal SD-OCT characteristics, and CME/ERM formation. Drainage with PFCL was associated with worse visual acuity, greater risk of persistent outer retinal discontinuity, and greater risk of CME as compared to drainage with PRB or PR. PR had a greater risk of ERM formation. Drainage through PRB had the best outcomes overall.

There are limitations to the study. This is a retrospective study, and even though baseline characteristics between the groups were similar, bias could have played a part in choosing the surgical approach. There were multiple surgeons involved so some of the variation could be due to surgeon variation. Further prospective clinical trials could help to confirm the findings found in this clinical study.

In summary, this was an excellent study showing that drainage through PRB could have better visual and outer retinal anatomical outcomes at 1 year after primary mac-off RRD repair as compared to PR and PFCL.