Does a mismatch between the centres of a diffractive trifocal intraocular lens and the pupil affect visual outcomes?

Purpose: To determine the effect of routinely encountered mismatch between the intraocular lens (IOL) centre and pupil centre on contrast sensitivity (CS), visual acuity (VA) and higher order aberrations (HOAs) one year after the implantation of a diffractive trifocal IOL following cataract surgery. Currently, the effects of multifocal IOL mismatch relative to the pupil centre are not well established. Methods: Prospective case series of 51 eyes undergoing phacoemulsification surgery with implantation of an AT LISA tri 839M or AT LISA TRI toric 939M diffractive trifocal IOL. Twelve months post-operatively, IOL positioning relative to the pupil centre, VA, aberrometry, tomography and standardised mesopic and photopic CS measurements were assessed. Correlation coefficients were derived for pupil centre to IOL centre distance, CS, VA and HOA. Results: The mean ± standard deviation time of follow up post-surgery was 458 ± 222 days. Uncorrected VA was better than logMAR 0.24 at all near, intermediate and distance in all eyes. The mean difference between the IOL centre and the centre of the pupil was 0.25mm ± 0.21mm. There was no statistically significant correlation between IOL-pupil centre mismatch for mesopic CS (p=0.318) or photopic CS (p=0.175). No statistically significant correlation was found between IOL-pupil centre mismatch and combined HOA root mean squares (p= 0.097). Conclusion: No statistically significant correlation was detected between trifocal IOL-pupil centre mismatch and contrast sensitivity, visual acuity, or higher-order aberrations within the observed range of mismatch (0.03-0.77 mm).