Impact of Incision Size and Architecture on Wound Stability and Astigmatism in Cataract Surgery: an Exploratory Study

One of the most recent advances in cataract surgery is microincisional phacoemulsification (MICS). Through small incisions of 2.0 mm and less the lens material is emulsified either bimanually or with a thin single coaxial hand-piece. The possible advantages are lower induced corneal astigmatism1, 2, possibly a lower incidence of infection due to higher resistance of the wound to deformation3 and a lower risk of complications such as iris prolapse during surgery in patients at risk such as with intraoperative floppy iris syndrome (IFIS). Additional factors that have to be taken into account are the construction and the position of the incision and the influence of the extraocular force on the wound morphology.4 Another effect that may influence the wound architecture is stromal hydration at the end of surgery.5 Wound architecture has recently been assessed6-9 using optical coherence tomography. Elkady et al.10 observed the wound architecture in MICS cases focusing on corneal thickness and the incision angle. However, none of these studies observed the effect of the wound architecture on post-operative astigmatism. Furthermore, all observations in the past have been performed in the post-operative period only and information concerning the wound architecture intra-operatively is missing. A recently launched CE-marked intra-operative OCT allows observing the wound architecture intra-operatively.

One aim of the study is to assess the influence of the intra-operative wound architecture using a similar grading system as used by Calladine and Packard (2007)7 on the resistance to deformation of the wound and the surgically induced astigmatism in MICS and small incision cataract surgery (SICS). In a second part of this exploratory study the effect of a hinged incision with a pre-cut should be assessed along the same line