Effect Of Pupil Size On Postoperative Spherical Aberration And Depth Of Focus In Eyes Implanted With An Extended Monofocal Intraocular Lens

Positive spherical aberration (SA) can be used to increase depth of focus postoperatively, and therefore reduce spectacle dependence, in patients undergoing cataract surgery or refractive lens exchange. This study aims to evaluate how pupil size impacts postoperative total spherical aberration and depth of focus following implantation of a non-diffractive enhanced monofocal intraocular lens (IOL) which aims to introduce positive SA.

Cathedral Eye Clinic, Belfast, United Kingdom

This retrospective study included 33 eyes of 33 patients who underwent cataract or refractive lens exchange surgery with implantation of the RayOne EMV IOL (Rayner, Worthing). Patients were divided into two groups based on postoperative pupil size: Group 1 (3–4 mm) and Group 2 (5–6 mm). Preoperative corneal SA at a 6 mm pupil size, postoperative total SA, and postoperative internal SA were measured and analysed. Normality was assessed using the Shapiro-Wilk test. Comparisons between groups were performed using an independent t-test for normally distributed variables and the Mann-Whitney U test for non-normally distributed variables

Preoperative corneal SA at a 6 mm pupil size was 0.23 ± 0.10 µm (0.00-0.43 µm) for Group 1 and 0.23 ± 0.08 µm (0.08-0.38 µm) for Group 2. Postoperative total SA was 0.06 ± 0.04 µm (0.00- 0.14 µm) for Group 1 and 0.20 ± 0.06 µm (0.04 - 0.31 µm) for Group 2, and postoperative internal SA was 0.09 ± 0.16 µm (-0.02-0.56 µm) for Group 1 and 0.10 ± 0.05 µm (0.04-0.21 µm) for Group 2. Statistical comparison between the two groups was conducted, with preoperative corneal SA and postoperative internal SA showing no significant difference (p=0.843, p=0.799 respectively). However, postoperative total SA was significantly higher in the large pupil group compared to the small pupil group (p<0.01). Defocus curves will also be compared between groups.

Larger pupils were associated with significantly higher postoperative total SA, while baseline corneal SA and postoperative internal SA remained comparable between groups. These findings suggest that pupil size is a key determinant of postoperative total SA, and this relates primarily to SA arising from the cornea rather than the IOL. Our analysis will include a comparison of depth of focus between the large pupil and small pupil groups.