Optical coherence tomography angiography findings after silicone oil tamponade for rhegmatogenous retinal detachment

Abstract

Aim: To describe retinal structural and microvascular changes using Swept source optical coherence tomography (SS‐OCT) and OCT angiography (OCT‐A) in patients with rhegmatogenous retinal detachment (RRD) treated by vitrectomy (PPV) and silicone oil (SO) tamponade and to identify the final visual acuity (VA) prognostic factors.Methods: In this retrospective study, patients were treated with PPV and SO tamponade for uncomplicated DRR. After SO removal, retinal thickness was assessed by SS‐OCT. The foveal avascular zone (FAZ) area, the fractal dimension (FD), the lacunarity (LAC) and the macular capillary vessel density (VD) in the superficial (PCS) and deep plexuses (PCP) and in the choriocapillaris (CC) were analysed.Results: Thirty‐one eyes were included in this study; 20 eyes (65%) had macula ‘OFF’ RRD. The mean post‐operative final VA was 3.2/10. Outer retinal defect was observed in 74.1% of the operated eyes. Central macular thickness (CMT) and parafoveal thickness were significantly decreased compared with healthy fellow eyes (p = 0.048; p = 0.029). Outer nuclear layer (ONL) and subfoveal choroid were significantly thinned in the operated eyes (p = 0.003; p = 0.017). The FAZ in PCS and PCP and was larger (p = 0.042; p = 0.032), the VD (total, parafoveal and parafoveal) in the PCP were significantly lower (p = 0.004; p = 0.012; p = 0.049) and the lacunarity (LAC) at the PCP level was significantly higher (p = 0.040) in the operated eyes than in the fellow eyes. The final VA was correlated with the defect of the outer retina (p < 0.002) and the VD in PCP (p = 0.0199). The duration of SO tamponade was signifcantly correlated with the outer retinal defect (p = 0.011), the enlargement of FAZ area (p = 0.001) and the VD in DCP (p = 0.002).Conclusion: SIO can lead to structural and vascular retinal ischaemic defect such as enlargement and irregularity of the FAZ and predominant PCP capillary abnormalities. These changes could reflect vascular hypoperfusion in eyes with SO tamponade and may represent a potential cause of retinal thinning and unexplained visual loss.