Scanning electron microscopy study of different one-piece foldable acrylic intraocular lenses after injection through microincisional cataract surgery cartridges

Purpose: To evaluate possible surface alterations of different models of one-piece foldable acrylic intraocular lenses (IOLs) after folding and ejecting process through 2.2-mm microincisional cataract surgery (MICS) cartridges. Methods: In this experimental laboratory study, the following IOLs were studied: Johnson&Johnson PCB00, HOYA iSert 251, Alcon AcrySof IQ SN60WF, Bausch&Lomb enVISTA MX-60. A total of 80 IOLs were analyzed. Twenty intraocular lenses of each type were studied: ten with a power of + 21 D ± 1 and ten with a power of + 28 D ± 1. IOLs were injected through a dedicated 2.2-mm MICS cartridge into a 50-mL vial containing 10 mL of deionized water. After rinsing and metallization process, scanning electron microscopy images were acquired. Results: All IOLs presented high-quality construction biomaterials. Some IOLs showed superficial scratches and tears on the optic surface, mainly positioned according to the direction of the stress induced by the folding process. In other cases, small superficial tears were seen in a more peripheral position. Conclusions: All lenses showed excellent surface quality. After folding and injection process some superficial scratches and tears of the IOL optic were detected in some models. Further studies are needed to assess the possible effects of those superficial damages on the optical quality of the IOLs.