Objective intraoperative assessment of vitreous f loaters localization in YAG-laser vitreolysis

Abstract

Purpose. To develop an optical method for assessing the localization of vitreous floaters in the vitreous cavity and to evaluate its efficacy compared to ultrasound assessment. Material and methods. The study included 35 patients (35 eyes) with Weiss ring. All the patients underwent echobiometry, as well as measurement of the distance from the vitreous floaters (VF) to the lens posterior capsule or towards retina by ultrasound and developed optical methods. Results. The mathematical modeling and the diopter difference between the slit-lamp oculars were used to develop a formula for the safe position of the VF in the vitreous cavity calculation. A comparative analysis of ultrasound and optical methods measurement results have showed their comparability. The values of the "limits of agreement" with 95% confidence intervals were: -0.02 [-0.07; 0.01] - the lower "consistency limit" and 0.25 [0.20; 0.29] - the upper "consistency limit". The average difference between methods with a 95% confidence interval was 0.11 [0.08; 0.13]. Conclusions. The developed optical method for assessing the safe localization of VF in the vitreous cavity showed comparable results with the ultrasound measurements. Futhermore, optical method allows to intraoperatively control the safe distance from the VF to the intraocular structures, thereby reducing the risk of YAG-vitreolysis complications. Key word: YAG laser vitreolysis, vitreous floaters, safe distance of vitreous floaters.