Intraocular lens insertion speed and structural changes in lens and cartridge system

Abstract

Intraocular lens insertion speed and structural changes in lens and cartridge system In the article by Ouchi about insertion speed and clear corneal wound structure, the results show statistically significant increases in wound size, number of wounds requiring hydration, and change in wound structure on ocular coherence tomography following slow intraocular lens (IOL) insertion. In laboratory examination, Ouchi also found an increase in the cartridge's vertical diameter when the IOL was loaded and vertical enlargement after delivery. Thus, his findings suggest that faster IOL insertion may lessen damage to the surgical wound. While faster IOL insertion can certainly promote enhanced wound safety, this technique is not necessarily without consequence. Our group similarly switched to the Infiniti Vision microcoaxial system using a 2.4 mm wound, Acrysof IQ IOL, and D-sized cartridges with Monarch III injectors (all Alcon Laboratories, Inc.) for IOL insertion. After almost 3 years and approximately 3000 uneventful IOL injections, we experienced a sudden increase in IOL trauma as well as cartridge aneurysm and cracking (Figure 1). Very similar complications occurred in the hands of multiple surgeons and across multiple supply lots over time. After extensive investigation including replacement of all Monarch injectors and discussion with the manufacturer, one of the key factors implicated was rapid IOL injection. Manufacturer recommendations for more moderately paced injections are informed by intensive assessments of the material properties of the cartridge and IOL.Modification of this techniquemay create unanticipated consequences for cartridge performance. While rapid IOL injection may reduce wound trauma, as Ouchi noted, it is not clear how well the IOL cartridge delivery system is able to cope with the presumed rapid increase in intraluminal pressure. Our experience suggests that more rapid delivery was associated with more frequent dysfunctional cracking of the cartridge during injection, with associated IOL andwound trauma.We speculate that slower delivery, while transmitting prolonged force to the wound wall, may result in a more gradual increase in pressure within the cartridge. In turn, we posit