Electron microscopy of laser capsulotomy edge: Interplatform comparison

Abstract

PURPOSE: To perform a morphological comparison of capsulotomy edges generated by commercially available femtosecond lasers with manual capsulorhexis. SETTING: Private clinic. DESIGN: Experimental study. METHODS: Capsules were collected using the following laser platforms and software versions: Lensx pre-soft-fit (version 2.16), Lensx post-soft-fit (version 2.20), Victus I (version 2.5), Victus II (version 2.7SP2), Catalys (version 2.15.13), and 10 manual. Scanning electron microscopy images were analyzed for the coefficient of variation (CoV) of pixilation along the capsule edge and homogeneity using gray-level co-occurrence matrix analysis. A qualitative assessment for anomalies, such as tags, was also made. RESULTS: The mean CoV values from the regression analysis showed the manual edge (n = 10) (101.6% ± 0.6% [SD]) was smoother than the edges created with Lensx pre-soft-fit (105.2% ± 1.2%) (P<.001), Lensx post-soft-fit (102.7% ± 1.4%) (P=.04), Victus I (104.9% ± 0.9%) (P<.001), Catalys (104.5% ± 1.6%) (P<.001), and Victus II (104.7% ± 1.6%) platforms. All lasers (0.19 to 0.23) (P<.001) except the Lensx post-soft-fit (0.25 ± 0.03) (P=.23) generated less homogenous capsulotomies than the manual technique (0.27 ± 0.04). Tags occurred with Lensx pre-soft-fit (5/10), Lensx post-soft-fit (1/10), Victus I (1/4), and Victus II (3/10) platforms. Misdirected pulses were seen with the Catalys (4/10) and Victus II (4/10) platforms, which used fluid interfaces. CONCLUSIONS: Laser capsulotomies are approaching the smoothness of the manual capsulorhexis. The Lensx post-soft-fit platform showed the least anomalies and the smallest difference for the CoV and homogeneity metrics compared with the manual method. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.