gms | German Medical Science

Purpose: A square-edge posterior lens surface has been considered an essential factor in preventing the development of posterior capsule opacification (PCO). In this study, we aimed to evaluate deviation from a perfect square of the micro-edge structure in different hydrophobic intraocular lenses (IOLs) using scanning electron microscopy (SEM).

Methods: The square-edge structure was studied in four different hydrophobic-acrylic IOL models (3 samples per model). The following IOLs were included: Aktis SZ-1 (Nidek, Japan), AcrySof IQ SN60WF (Alcon, USA), Tecnis PCB00 (Johnson & Johnson Vision, USA) and iSert 250 (Hoya, Japan). The posterior-lens surface of the IOLs was evaluated with an SU 8000 (Hitachi, Japan) scanning electron microscope. The IOLs’ posterior edge was examined and photographed with x1000 magnification. Recorded images were analyzed to find the area of deviation from a perfect square. Following a standardized protocol, the analysis was performed for a 40-µm and 60-µm reference square.

Results: The SEM analysis confirmed a good reproducibility of the micro-edge structure in IOLs of one (the same) model. The mean (±standard deviation) area deviation from the 40-µm square was 150 ±25µm² for the Aktis, 91 ±17µm² for the AcrySof IQ, 197 ±11µm² for the Tecnis, and 94 ±14µm² for the iSert. For the 60-µm square, it increased to 287 ±17µm² for the Aktis, 132 ±36µm² for the AcrySof IQ, 402 ±6µm² for the Tecnis, and 179 ±19µm² for the iSert. SEM images showed different levels of surface roughness of the studied models.

Conclusions: We showed that the posterior edge of the studied square-edge hydrophobic-acrylic IOLs characterizes varying levels of deviations from the perfect square. The AcrySof IQ and the iSert IOLs demonstrated the smallest deviation parameter, which may result in more effective PCO prevention