Inspection of the lens thickness with preoperative biometric measurements prevents an erroneous interpretation of posterior capsule during FLACS

Abstract

Optical opacity reduces quality of biometry images, making it potentially difficult to find the correct location for irradiation during femtosecond laser-assisted cataract surgery (FLACS). After experiencing a case of posterior capsule (PC) rupture because of optical opacity, we started lens thickness (LT) inspection, which indicates comparison of between intra- and pre-operatively measured LT. We retrospectively investigated the effectiveness of the LT inspection. One observer reviewed all FLACS treatment summaries for 3 years by CATALYS in the Jikei University Hospital, Tokyo. Based on the lines defining the PC on intraoperative OCT images, all cases were classified into three groups: undescribed, appropriate and inappropriate PC. Among the 1070 cases, 1047 cases had appropriate PC. In 19 cases, the PC line was undescribed because of dense cataract. Among 474 cases with no inspection, 4 cases had an inappropriate PC. Whereas, in 596 cases with the LT inspection, there was no case of an inappropriate PC. LT inspection significantly reduced the cases with inappropriate PC. The safety margins normally work to prevent severe complications. However, rare outlier cases had a high risk of severe complications. We propose LT inspection could be the most practical and convenient way for safety surgery.

Intraoperative Anterior Segment Optical Coherence Tomography in the Management of Cataract Surgery: State of the Art

“…In their study, Kurosawa et al reported a case of posterior capsule dehiscence induced by misdirected laser irradiation, caused by the detection of a high OCT intensity area in the anterior vitreous (misinterpreted as the posterior capsule) [14]. They consequently proposed a method to avoid this complication, called LT inspection: it stands for comparing pre-operative LT (detected with IOL Master 700 and CASIA2, TOMEY) with intraoperative LT (detected with Catalys' i-OCT) before laser irradiation and, eventually, to manually correct intraoperative data based on this comparison.…”

“…During FLACS, precise detection of radiation sites is critical to correct the direction of spots and to avoid complications. Kurosawa et al demonstrated that LT inspection could guide the surgeon in adjusting laser settings and avoiding posterior capsule breaks [14].…”