The assessment of the degree of Silicone oil emulsification using Ultra-wide fundus photography and Optical coherence tomography

Abstract

Purpose: The purpose of this study was to assess the degree of silicone oil (SO) emulsification using ultra-wide fundus photography and optical density ratio (ODR) in swept-source optical coherence tomography (SS-OCT). Methods: This retrospective study included 51 eyes of 51 patients who underwent intravitreal SO tamponade with vitrectomy. Two weeks after SO tamponade and immediately before SO removal, ultra-wide fundus photography and SS-OCT were performed. Based on the degree of emulsified droplets in ultra-wide fundus photography, SO emulsification was qualitatively graded from 0 to 4. ODRs were calculated by dividing the optical density value in the optic cup by the optical density value of SO near the retinal surface. We analyzed the change in the grade of SO emulsification and ODR over time. Results: The mean time from SO tamponade to SO removal was 4.9 ± 3.7 months. The most common cause of SO tamponade was rhegmatogenous retinal detachment (51%). Average intraocular pressure 2 weeks after SO tamponade was 17.2 ± 2.9 mmHg and 18.2 ± 4.2 mmHg immediately before SO removal. SO emulsification, as graded by ultra-wide fundus photography, was 2.1 ± 1.4, and ODR ratio was 1.13 ± 0.24 based on SS-OCT. Longer duration of SO tamponade was associated with higher grade of emulsification in ultra-wide fundus photography and an increased in ODR in SS-OCT (both P<0.01). There was a statistically significant correlation between the grade of SO emulsification in ultra-wide fundus photography and ODR ratio in SS-OCT (P=0.028). Conclusion: Our study suggested that ultra-wide fundus photography and SS-OCT could be used to determine the degree of SO emulsification objectively, which may be useful to decide the time of removal of SO prior to occurrence of associated complications.