Enlargement of Incision Width during Phacoemulsification and Folded Intraocular Lens Implant Surgery

Purpose: The authors investigated the dimensional stability of incisions during phacoemulsification and small-incision intraocular lens (IOL) implantation. Methods: Forty-six eyes undergoing temporal clear corneal phacoemulsification and folded silicone IOL implantation were measured with an internal-incision gauge after initial keratome entry, cataract removal, and folded IOL implantation. Results: The initial incision created by a diamond keratome was wider than the physical keratome width by a mean of 0.16 mm. After completion of phacoemulsification and irrigation/aspiration, the incision further widened by a mean of 0.09 mm. Both forceps insertion of a three-piece silicone IOL and injector insertion of a plate haptic silicone IOL resulted in further incision enlargement by a mean of 0.26 mm. Widening of the incision before IOL insertion did not eliminate even further incision expansion during the IOL insertion. Conclusions: The phacoemulsification incision enlarges at each step of the procedure. Irreversible incision stretching or incision tearing occurs, rather than reversible elastic incision deformation. Clinical studies that assume the initial keratome size equals the final incision size may be erroneous.