Incidence, risk factors, and clinical characteristics of unexplained visual loss after intraocular silicone oil for macula-on retinal detachment

Purpose: To investigate the incidence, risk factors, and clinical characteristics of unexplained visual loss after macula-on rhegmatogenous retinal detachment (RRD). Methods: Retrospective cohort of patients with primary macula-on rhegmatogenous retinal detachment treated by vitrectomy with gas or silicone oil (SO) tamponade in 2011 and 2012. Outcome was unexplained visual loss (>2 Snellen lines) 2 months after the last vitrectomy. Results: Incidence of unexplained visual loss was 0.7% (1/151) in patients treated by gas and 29.7% (11/37) in patients treated by SO (P 0.001). Visual loss occurred both during SO tamponade and after removal. Cases underwent optical coherence tomography, perimetry, microperimetry, fluorescein angiography, and visual evoked potentials. Patients with unexplained visual loss after SO tamponade showed a small scotoma within the central 2° on microperimetry. Duration of SO tamponade was the only statistically significant factor related to the incidence of unexplained visual loss (P 0.001). Conclusion: Incidence of SO-related visual loss was 30% with duration of tamponade as the only risk factor. This study is the first to apply microperimetry in these patients, which showed a distinct pattern of a small central scotoma. Therefore, microperimetry can be of great value in the diagnostic workup of patients with unexplained visual loss after vitrectomy.