SILICONE OIL TAMPONADE EFFECT ON MACULAR LAYER THICKNESS AND VISUAL ACUITY

PURPOSE: To evaluate the influence of silicone oil (SO) tamponade on retinal layers thickness and visual acuity in patients who underwent pars plana vitrectomy for rhegmatogenous retinal detachment. METHODS: This is a retrospective case series of consecutive patients who underwent pars plana vitrectomy for rhegmatogenous retinal detachment with SO tamponade. Visual acuity and central macular thickness were measured with SO and at least a month after SO removal (SOR). Patients with insufficient or poor-quality images or macular pathologies such as macular edema or epiretinal membranes were excluded. RESULTS: Forty-one patients with an average age of 56.1 ± 15.2 years were included, and 54% presented with fovea ON. Average tamponade duration was 151 ± 54 days. Central macular thickness of the operated eye increased from 249 ± 50 µm before to 279 ± 48 µm after SOR (P < 0.001), compared with 281 ± 21 µm of the fellow eye (P < 0.001). A mean change of 26 µm was found in the internal layers (P < 0.001). Visual acuity improved from 0.85 ± 0.97 logarithm of the minimal angle of resolution (logMAR; Snellen 20/140) with SO tamponade to 0.34 ± 0.28 logMAR (Snellen 20/43) after SOR (P < 0.001). For patients with fovea ON and without significant cataract, visual acuity was 0.19 ± 0.16 logMAR (Snellen 20/30) at presentation, 0.59 ± 0.41 logMAR (Snellen 20/80) with SO (P = 0.005), and 0.18 ± 0.15 logMAR (Snellen 20/30) after SOR (P = 0.003). CONCLUSION: Silicone oil tamponade causes a transient decrease in central macular thickness, mainly in the inner layers. After SOR, central macular thickness resembles to the fellow eyes. The mechanism for this effect is unclear, but apparently has no influence on final visual acuity.