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The researchers examined the edges of the anterior capsulotomies macroscopically and microscopically using trypan blue staining to improve visualization. In addition, one eye from each capsulotomy group was prepared for further assessment with scanning electron microscopy. Those investigations showed there were some irregularities in the edges of capsulotomies performed with the Fugo Blade. However, following an analysis of their characteristics against the background of previous research delineating the mechanisms of radial tear formation and extension after anterior capsulectomy, the investigators concluded the margin irregularities were not likely to be sites of radial tear formation.
Manual continuous curvilinear capsulorhexis represents the standard technique for anterior capsulotomy because of its advantage for minimising the risk of lens capsule tearing. However, it is not easy to perform in some situations, such as in eyes where visibility is decreased. Therefore, we need to have alternative techniques that can be used safely in cases when CCC is challenging," said Liliana Werner, MD, PhD who co-authored the study. "Capsulotomy with the Fugo Blade can be readily performed even when visibility is poor, and based on the results of this study, which to our knowledge provides the first microscopic documentation of the edges of capsulotomies obtained with the Fugo Blade, that technique also seems to fulfill our need for equivalent safety, at least relating to radial tear formation," said Dr. Werner.The edge irregularities noted in eyes that underwent Fugo Blade capsulotomy were characterised as being regularly spaced, centrally directed and originating from the posterior aspect of the capsulotomy edge while having smooth edges in their base (anterior aspect). "Previous research by Dr. Apple, Dr. Ehud Assia, and colleagues (Assia EI, Apple DJ, Barden A, et al. An experimental study comparing various anterior capsulotomy techniques. Arch Ophthalmol 1991; 109:642-647) has demonstrated that the configuration of the edge irregularities occurring with Fugo Blade capsulotomy is of a type that does not interfere with the dynamics of the capsulorhexis sphincter and so does not show a tendency towards radial tear formation. Unlike a sharp notch directed outward, a tag at the margin of a circular capsulectomy that is centrally directed and has smooth edges at its base does not interfere with the integrity of the molecular interconnections," Dr. Werner explained. Consistent with previous studies, the analyses confirmed that the capsulotomy margin associated with use of the CCC technique was smooth and intact while the can-opener capsulotomy technique could result in an edge configuration associated with a risk for radial tear extension. Following can-opener capsulotomy, the edge margin was noted to have sharp notches directed outwards that were also irregularly spaced and shaped. Of the two capsulotomies performed using the can-opener, one exhibited a radial tear extending directly towards the equator. The research was support in part by a grant from Research to Prevent Blindness, Inc, but the investigators did not receive any industry funding. The Fugo Blade is approved in the United States for use in capsulorhexis procedures. It is being evaluated in several other ophthalmic surgery settings including phacofragmentation and filtration surgery. Dr Werner's co-authors were Andrea M. Izak MD, David J. Apple, MD and Suresh K. Pandey MD. Liliana Werner MD PhD
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