Capsulotomy Morphology in Cataract Surgery: A Comparison of 5 Femtosecond Lasers.

Purpose: To compare the capsulotomy rim morphology of anterior lens capsules obtained by five femtosecond laser-assisted cataract surgery platforms: Catalys, FEMTO LDV Z8, LensAR, LenSx, and Victus.

Setting: University Eye Hospital, Basel, Switzerland.

Design: Experimental study.

Methods: Anterior lens capsules from six interventions per laser platform were collected (N = 30). Four of each were assessed under light microscopy (n = 20), and two were assessed under scanning electron microscopy (n = 10). A qualitative evaluation of all samples was conducted, as well as a semi-quantitative analysis of the extent of irregularities present in light microscopy samples. Dunn's multiple comparisons test was conducted to determine which lasers produced significantly smoother capsulotomies.

Results: Irregularities along the lens capsule rim were observed in all samples. Distinct irregularities were observed for Catalys (unconnected laser pulses bordering the capsulotomy), FEMTO LDV Z8 (numerous additional rows of laser pulses), and LensAR (at least one section with multiple rows of laser pulses). Victus demonstrated a significantly higher degree of smoothness of capsulotomy (median = 306°) compared to Catalys (median = 171°) (P = 0.02). The medians for other laser platforms fell between these values.

Conclusions: Different laser platforms produce morphologically and quantitatively distinct irregularities, which may influence capsulotomy strength differently. FEMTO LDV Z8, a low-energy laser, did not produce a smoother capsulotomy than the high-energy lasers. Our results suggest that, with current technologies, the precision of the laser is more important than the pulse energy in determining the regularity of the capsulotomy surface.