Effect of silicone oil on peripapillary capillary density in patients with rhegmatogenous retinal detachment

Abstract

Purpose: To evaluate the effect of silicone oil (SO) on peripapillary blood flow using OCT angiography.

Methods: This prospective case series recruited patients with unilateral rhegmatogenous retinal detachment (RRD) who underwent vitrectomy and SO tamponade. Patients were examined before SO removal and at 10 days, 1 month, and 3 months after SO removal on a spectral domain OCT angiography device (RTVue XR Avanti, Optovue Inc., CA, USA) for the measurement of radial peripapillary capillaries (RPC) vessel density (VD) in global field, superior hemifield, and inferior hemifield. Changes in RPC VD following SO removal were compared between affected eyes and contralateral eyes.

Results: Twenty-two patients were analyzed. The average duration of SO tamponade was 101.3 days (range, 90 to 119 days). After SO removal, global RPC VD increased by 1.3% (95%CI, 0.3 to 2.3%), compared with a - 0.4% (95%CI, - 1.4 to 0.7%) change in contralateral eyes (P = 0.007). The increase in RPC VD after SO removal mainly occurred in the superior hemifield, which was 1.6% (95%CI, 0.6 to 2.7%). The increase in RPC VD in the inferior hemifield was 1.0% (95%CI, - 0.2 to 2.1%) after SO removal.

Conclusions: We detected a mild increase in peripapillary capillary density after SO removal, mainly in the superior hemifield. Our results suggested that SO tamponade could have negative effect on peripapillary blood flow, possibly by capillary compression.

Keywords: Optic neuropathy; Optical coherence tomography angiography; Radial peripapillary capillaries; Rhegmatogenous retinal detachment; Silicone oil.

Fig. 1

Measuring radial peripapillary capillaries (RPC) vessel density (VD) based on Garway-Heath’s map. (Left) The representative 4.5 mm × 4.5 mm en face OCT angiography image is centered on optic nerve head. The peripapillary area is overlaid by annular contour lines with 2 mm and 4 mm diameter around disc margin. The peripapillary area is further divided into eight sectors according to Garway-Heath’s map. (Right) The built-in software automatically calculates RPC VD based on Garway-Heath’s map. The global RPC VD (arrow) is measured from the 360-degree annular peripapillary area. The RPC VD of the superior (asterisk) and inferior (triangle) hemifield is measured from the superior four sectors and the inferior four sectors, respectively

Fig. 2

The whisker plot of global radial peripapillary capillaries (RPC) vessel density (VD) measured before and at 10 days, 1 month and 3 months after silicone oil removal (SOR) in patients who underwent pars plana vitrectomy and silicone oil tamponade for rhegmatogenous retinal detachment repair. The mean, median, and 25th to 75th percentile of RPC VD is shown by cross, horizontal line, and box, respectively. An increase in peripapillary vessel density after SOR is revealed by repeated measures ANOVA (F = 5.417, P = 0.002). The results of Bonferroni’s post hoc test are indicated by P values above horizontal bars