Femto capsulotomy

After preclinical work performing capsulotomies with an OCT-guided femtosecond laser in porcine and human cadaver eyes, researchers performed the same procedure in 39 patients as part of a prospective randomised study of femtosecond laser-assisted cataract surgery. The femtosecond laser-created capsulotomies were more precise in size and shape than manually created capsulorhexes, they report. In the patient eyes, the deviation from the intended diameter of the resected capsule disk was 29 μm ± 26 (SD) for the laser technique and 337 ± 258 μm for the manual technique. The mean deviation from circularity was six per cent and 20 per cent, respectively. The centre of the laser capsulotomies was within 77 ± 47 μm of the intended position. All capsulotomies were complete, with no radial nicks or tears. The researchers also were able to assess the strength of laser capsulotomies in the porcine eyes. They found that the strength decreased with increasing pulse energy: 152 ± 21 mN for 3 μJ, 121 ± 16 mN for 6 μJ, and 113 ± 23 mN for 10 μJ. The strength of the manual capsulorhexes was 65 ± 21 mN. Even in the most experienced hands, an optimal capsulorhexis is not always achieved with the standard approach. Femtosecond lasers are able to create precise, customisable incisions in ocular tissue without collateral damage. The current study using the OCT-integrated femtosecond laser system allowed  placement of cutting patterns in ocular tissue, allowing the surgeons to achieve a level of precision unattainable with manual and mechanical techniques.

N. Friedman et al., JCRS, “Femtosecond laser capsulotomyâ€, Volume 37, No. 7 1189-1198.