Authors: Nesrine Abroug, Imen Ksiaa, Wejdene Nabi, Marouane Lahdhiri, Sana Khochtali, Moncef Khairallah

Affiliation:  Department of Ophthalmology, Fattouma Bourguiba University Hospital, Faculty of Medicine, University of Monastir, Monastir, Tunisia

Purpose: To investigate the size and shape of the foveal avascular zone (FAZ) after successful macula-off rhegmatogenous retinal detachment (RRD) repair using swept source OCT angiography (SS OCTA).

Methods: A prospective comparative cross-sectional study including 21 eyes of 21 patients with macula-off RRD that were successfully repaired. The size of the superficial FAZ was assessed by its area, length of perimeter, and Feret’s diameter, and the shape by the circularity, axial ratio, roundness, and solidity. The correlations between each parameter and the clinical and OCT findings were statistically determined. The unaffected fellow eyes were used as controls.

Results: The mean initial BCVA was 1.92 ± 0.41 Log MAR (20/2000 Snellen’s equivalent). The mean BCVA at OCTA acquisition (3 months) was 0.78 ± 0.39 Log MAR (20/100 Snellen’s equivalent) (p<0.001). FAZ was significantly larger (323.09 +/- 129,03  µm² vs 245.27 +/- 93.15 µm²; p=0.038), with longer perimeter (2.31 ± 0.35 mm vs 2.07± 0.31mm; p=0.048), and irregular shaped (mean circularity : 0.73 +/- 0.72 vs 0.78 +/- 0.5; p=0.019 and  mean solidity : 0.90 ± 0.02 vs 0.93 ± 0.02; p=0.002) in operated eyes than in the control group. The average Feret’s diameter was 0.77 ± 0.10 mm vs 0.71± 0.88mm (p=0.076). The average axial ratio was 1.25 ± 0.20 vs 1.22 ± 0.22 (p=0.531), and the average roundness was 0.81 ± 0.11 vs 0.83 ± 0.11 (p=0.531). Mean central foveal thickness (CFT) was significantly lower in operated eyes than in control eyes (178.23 +/- 40.59 µm vs 247.44 +/- 38.2 µm (p<0,001). There was a significant inverse correlation between FAZ area and post-operative outer nuclear layer thickness (r=-0.520, p=0.016) and CFT (r=-0.571, p=0.007) in operated eyes. There was no significant correlation between the postoperative visual acuity and FAZ parameters.

Conclusion: Enlargement and irregularities of FAZ after successful macula-off RRD repair, as demonstrated by SS OCTA, might suggest an ischemic macular damage caused by RRD that may affect post-operative functional outcome.

Financial disclosure: No