The Extent of Silicone Oil Emulsification Revealed by Ultra-wide-field Fundus Photography and Optical Coherence Tomography

Abstract

Purpose: We assessed the extent of silicone oil (SO) emulsification using ultra-wide-field fundus photography (wFP) and the reflective ratios of swept-source optical coherence tomography (SS-OCT).Methods: We retrospectively enrolled 51 eyes of 51 patients who underwent intravitreal SO tamponade with vitrectomy. Two weeks after SO tamponade and immediately before SO removal, ultra-wide-field fundus photography and SS-OCT were performed. Based on the numbers of emulsified droplets in the ultra-wide-field fundus photographs, SO emulsification was qualitatively graded from 0 to 4. Reflective ratios were calculated by dividing the OCT reflectivity of the optic cup by the OCT reflectivity of SO near the retinal surface. We analyzed the changes in the SO emulsification grade and the reflective ratio over time (RR2/RR1).Results: The SO emulsification grade revealed by ultra-wide-field fundus photography was 2.12 ± 1.29, and the mean SS-OCT RR2/RR1 value was 1.14 ± 0.22. A longer duration of SO tamponade was associated with a higher emulsification grade on ultra-wide-field fundus photography and an increase in the RR2/RR1 value (both <i>p</i> < 0.01). We found a significant correlation between the SO emulsification grade on ultra-wide-field fundus photography and the SS-OCT RR2/RR1 (<i>p</i> = 0.028).Conclusions: Ultra-wide-field fundus photography and SS-OCT can be used to determine objectively the extent of SO emulsification; this may indicate the appropriate SO removal time any complication.