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Findings from an updated analysis of outcomes at a single center reaffirm the safety of femtosecond laser capsulotomy by showing it is associated with a low rate of anterior capsule tears.
Reviewed by Timothy V. Roberts, MD
Sydney, Australia-Findings from an updated analysis of outcomes at a single center reaffirm the safety of femtosecond laser capsulotomy by showing it is associated with a low rate of anterior capsule tears.
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Cataract surgeons at the Vision Eye Institute, Sydney, Australia, began performing femtosecond laser-assisted cataract/refractive lens exchange surgery in April 2011, using one femtosecond laser system (LenSx, Alcon Laboratories). They summarized their experience in 1,500 consecutive eyes operated on between April 2011 and March 2012 and reported an anterior capsular tear rate of 0.31% [Roberts TV, et al. Ophthalmology. 2013;120(2):227-233], said Timothy V. Roberts, MD, medical director and consultant ophthalmic surgeon and senior clinical lecturer, University of Sydney.
In a follow-up report [Roberts TV, et al. J Cataract Refract Surg. 2015 May;41(5):1109-10], the surgeons reviewed data from 3,355 consecutive procedures performed between April 2012 and October 2014, and they identified 7 eyes (0.18%) with a break in the anterior capsule rim. However, among eyes operated on after the laser was upgraded with the introduction of a new, soft contact lens patient interface (SoftFit, Alcon Laboratories), the anterior capsule tear rate was just 0.08%.
The most recent analysis included over 3,800 eyes that underwent laser anterior capsulotomy between April 2012 and September 2015, and it found that the anterior capsule tear rate remained around 1 in 1,000 cases.
“Based on initial studies, it was well accepted early on that use of the femtosecond laser compared with a manual technique enabled surgeons to more consistently achieve an accurately sized and shaped capsulotomy,” said Dr. Roberts. “Other reports, however, have raised some discussion about the quality of the laser-created capsulotomy,”
Advances in technology
“The significant advances in laser technology, patient interfaces, and surgical technique have now resolved this issue that, along with capsular block syndrome, was noted in the early days of laser cataract surgery,” he added. “Our experience encompasses routine and complex cases, and it indicates that with current hardware and software, the femtosecond laser is a reliable tool for creating capsulotomies that are safe, intact, round, and of intended size.”
Dr. Roberts noted that various studies showed that the ultrastructural appearance of the laser-created capsulotomy differs from that of a manually torn capsule opening [Bala C, et al. J Cataract Refract Surg. 2014;40(8):1382-1389].
“But there is no real evidence that this difference has clinical relevance as large studies are showing very low rates of capsular tears with laser-cut capsulotomies,” he said.
Low rate among all lasers
Dr. Roberts pointed out that other investigators using the LenSx and other femtosecond laser platforms for capsulotomy similarly find a low rate of anterior capsule tears. Supporting this comment, he cited a paper from surgeons at Moorfields Eye Hospital, London, that reported an anterior capsule tear rate of 0.1% for a series of 1,000 eyes operated on with the Catalys Precision Laser System (Abbott Medical Optics/Johnson & Johnson) [Day AC, et al. J Cataract Refract Surg. 2014;40(12):2031-2034].
“It is plausible that some eyes have an intrinsically weak capsule that makes them susceptible to develop a tear as a result of surgical manipulations, regardless of whether the capsulotomy was created with a femtosecond laser or manually,” explained Dr. Roberts. “Use of the femtosecond laser, however, seems to have an advantage for minimizing capsulotomy-related complications, and it may be particularly useful in certain complicated eyes, such as white cataracts.”
Surgical techniques that will help to reduce the risk of anterior capsular tears include dividing a dense cataract into four to six small pieces, being careful not to stretch the capsule edge with the phaco tip and side instrument or the I/A tip, and maintaining a stable anterior chamber that will prevent trampolining of the capsule and iris.
Tim Roberts, MD
This article is based on a paper presentation by Dr. Roberts at the 2016 ASCRS Symposium. Dr. Roberts is or has been a consultant to Alcon Laboratories, Pfizer, Abbott Medical Optics/Johnson & Johnson, Allergan, Device Technologies, and Bausch + Lomb.