Differences in metamorphopsia measurements and optical coherence tomography morphological changes following rhegmatogenous retinal detachment repair: Analysis of a randomized controlled trial comparing pneumatic retinopexy to pars plana vitrectomy

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Authors: Tina Felfeli, Roxane J. Hillier, Carolina Francisconi, Verena Juncal, Michael Y. K. Mak, Louis R. Giavedoni, David T. Wong, Alan R. Berger, Filiberto Altomare, Radha P. Kohly, Rajeev H. Muni
Author Disclosure Block: T. Felfeli: None. R.J. Hillier: None. C. Francisconi: None. V. Juncal: None. M.Y.K. Mak: None. L.R. Giavedoni: None. D.T. Wong: None. A.R. Berger: None. F. Altomare: None. R.P. Kohly: None. R.H. Muni: None.

Abstract Body:

Purpose: To compare metamorphopsia measurements and optical coherence tomography (OCT) morphological changes in patients randomized to primary pneumatic retinopexy (PnR) vs pars plana vitrectomy (PPV) for rhegmatogenous retinal detachment (RRD) repair.

Study Design: Randomized controlled trial

Methods: Patients with 1-year follow-up from The Pneumatic Retinopexy versus Vitrectomy Outcomes Randomized Controlled Trial (PIVOT) conducted between August 2012 to May 2017 were included in the study. The trial included patients with a single retinal break, or group of breaks no larger than 1 clock hour, above the 8 and 4 o’clock meridians. Stratified randomization by macular status was performed. Severity of metamorphopsia at 1 year was quantified using M-Charts, a diagnostic tool for quantification of vertical (MV) and horizontal (MH) metamorphopsia with scores of 0.2-2.0 degrees of visual angle. Foveal morphological changes on OCT at 1 year were assessed by two masked independent graders with disagreement adjudicated by a third masked grader.

Results: A total of 176 eyes (176 patients) were randomly assigned to primary PnR vs PPV. The PnR group had 49% macula off vs 51% in the PPV group (p=0.763). Mean age was 60.7±10.1 and 60.3±7.8 years in the PnR and PPV groups, respectively (p=0.952). 1-year ETDRS was 79.9±11.5 vs 75.0±14.7 in the PnR and PPV groups, respectively (p=0.024). Mean MV scores (n=126) were 0.14±0.29 in the PnR group and 0.28±0.42 in the PPV group (p=0.026). Mean MH scores (n=126) were 0.15±0.33 in the PnR group and 0.24±0.46 in the PPV group (p=0.247). The 1-year ETDRS was significantly associated with MV and MH scores (p=0.002, p<0.001). OCT assessment at 1 year (n=149) revealed that the proportion of patients with interdigitation zone (IDZ) disruption was lower in PnR group compared to PPV (61% vs 78%, p=0.027). The proportion of patients with external limiting membrane disruption was lower in the PnR compared to the PPV group (8% vs 20%, p=0.034) as was the proportion of patients with cystoid macular edema (12% vs 25%, p=0.035). There was no significant difference between groups in the proportion of patients with epiretinal membrane, foveal contour abnormality, subfoveal fluid, inner and outer retinal folds, ellipsoid zone disruption, and retinal pigment epithelium disruption. IDZ disruption was associated with presence of vertical and horizontal metamorphopsia (p=0.042, p=0.002). MH scores were associated with cystoid macular edema (p=0.034) but no signification association between MV and MH scores with epiretinal membrane was noted (p=0.297, p=0.441).

Conclusions: Primary PnR for RRD repair results in superior visual acuity and reduced vertical metamorphopsia compared to PPV at 1 year. Abnormalities of the interdigitation zone and external limiting membrane were significantly lower in the PnR group. The reduced postoperative vertical metamorphopsia with PnR at 1 year is associated with reduced disruption of the IDZ on OCT.

This project was supported by the Retina Foundation of Canada 2017 Junior Clinical Research Grant.