We commend Luo and associates for their recently published study, in which they shared their doubts regarding coaxial-microincisional cataract surgery (C-MICS). Currently, the barrier of a 2-mm corneal incision represents more of a psychological landmark, although we are confident that further technological advancements will make C-MICS the standard in the near future. This is because the transition from standard coaxial phacoemulsification to C-MICS is easy, requiring a very minimal learning curve.
We would like to emphasize one of the findings of the study: the increased corneal edema in the area of the incision observed in the group of eyes undergoing surgery through a 1.8-mm incision. Our experience was similar, associated with an intraoperative feeling of reduced maneuverability and increased wound stretch, particularly in eyes with a deep anterior chamber. We attributed it to the very tight fit of the required irrigation sleeve through the smallest corneal incision for C-MICS available to date. Notably, the same system (phacoemulsification tip plus sleeve) also is indicated for surgery through a 2.2-mm incision, with a completely different feeling. Although a shorter tunnel may overcome that uncomfortable feeling, it also may lead to a less stable incision resulting in a theoretical increased risk of postoperative endophthalmitis, therefore is not favored by us.
We believe it questionable to use 2 different phacoemulsification machines, the Stellaris (Baush & Lomb, Rochester, New York, USA) versus the Infinity System (Alcon Laboratories, Fort Worth, Texas, USA). Given that the authors intended to study several characteristics and to individuate the incision size associated with the greatest surgical efficiency, different machines do not represent the best choice, in our view. This is particularly the case if considering that the chosen systems are equipped with a different tip movement (longitudinal versus torsional) and different fluidics (venturi versus peristaltic pump). Also, the authors should clarify how they recorded the cumulative dissipated energy (one of the main outcome measures of the study), given that the 2 phacoemulsifiers do not provide the surgeons with comparable values. Finally, we noted that the authors performed their statistical analysis on wound enlargement considering the wound size as a continuous variable. The wound size was assessed during surgery by means of microincision gauges, with progressive steps of 0.1 mm. Therefore, we believe their method of analyzing the results was not appropriate: the results instead could be expressed in a percentage of eyes with at least 0.1-mm wound enlargement in the different groups, and the statistics should be re-evaluated in light of this.