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An analysis including almost 3,000 eyes operated on with modern femtosecond laser technology found an anterior capsule tear rate of
Reviewed by Tim Roberts, MD
Sydney-Significant evidence in the literature shows that use of a femtosecond laser consistently creates a capsulotomy with precise geometry, circularity, and sizing.
Now, data from large studies also establish that the laser procedure is associated with a very low rate of anterior capsule tears, said Tim Roberts, MD.
“These are important points because the quality of the anterior capsulotomy is crucial to the safety and refractive outcome of cataract surgery,” said Dr. Roberts, consultant ophthalmic surgeon and clinical senior lecturer, University of Sydney and medical director, Vision Eye Institute Australia.
Dr. Roberts and colleagues at the Vision Eye Institute, Chatswood, reported their experience using a femtosecond laser platform (LenSx, Alcon Laboratories). In their prospective, consecutive series of 3,842 eyes, 7 eyes (0.18%) were identified as having a break in the anterior capsule rim.
However, further analyses showed the rate dropped significantly to 0.08% when the new soft contact lens patient interface (SoftFit) replaced the original rigid curved interface (0.08%, 2/3108 eyes versus 0.68%, 5/734 eyes, p = 0.004).
Dr. Roberts emphasized that the eyes in his group’s series was a consecutive cohort and included complex cases that may be at increased risk for anterior capsule tear-e.g., eyes with floppy iris syndrome, white cataract, pseudoexfoliation, and traumatic zonulopathy.
Reviewing the literature on this topic, Dr. Roberts cited a recent paper that similarly reported a very low anterior capsule tear rate of 0.1% when analyzing outcomes for 1,000 eyes operated on at Moorfields Eye Hospital, London, using another femtosecond laser (Catalys, Abbott Medical Optics) [Day AC, et al. J Cataract Refract Surg. 2014;40:2031-2034].
In contrast, an earlier study using the Catalys system reported a high rate of 1.8% in 804 eyes [Abell et al. Ophthalmology. 2014;121:17-24].
Dr. Roberts said that the latter paper stirred controversy about femtosecond laser capsulotomy by hypothesizing that treating the capsule with a laser-irrespective of the platform used-may produce a germinative defect, rendering the capsule intrinsically weak.
“The high complication rate in the paper by Abell et al. focused attention on laser settings and surgical techniques used in laser cataract surgery,” he said. “There is no doubt that there will be ultrastructural differences in the capsule when the capsulotomy is created with a laser versus manually, but the important question is: From an evidence-based perspective, what, if any, are the clinical implications of these differences?”
When looking at the most recent published results of nearly 5,000 consecutive laser procedures from their group [Roberts et al. J Cataract Refract Surg. 2015;41:1109-1110] and the Moorfields group, using different laser systems, surgeons can now be confident that optimal laser settings and appropriate surgical technique will result in a perfectly circular, evenly sized and intact capsulotomy in nearly every case, Dr. Roberts noted.
He added that the advanced new patient interface for the femtosecond laser platform and refinement of laser settings and surgical technique over time have been “game changers” for achieving free-floating capsulotomies with an extremely low rate of anterior capsule tear.
Tim Roberts, MD
This article was adapted from Dr. Roberts’ presentation at the 2015 meeting of the American Academy of Ophthalmology. Dr. Roberts is or has been a consultant to Abbott Medical Optics, Alcon Laboratories, Allergan, Bausch + Lomb, Device Technologies, and Pfizer.