Comparing Defocus Curves Of Three Diffractive Multifocal Intraocular Lenses Over A Base Refractive Multifocal Design: A Case Series

Multifocal intraocular lenses (IOLs) aim to reduce dependence on glasses by distributing light across multiple focal points. This case series compares the visual performance of three diffractive multifocal IOLs with base refractive multifocal optics, implanted binocularly. Defocus curves were used to assess visual restoration efficiency, evaluate range of vision, visual acuity at various distances, and binocular complementarity.

Clínica Privada de Ojos Dr. Enrique Alza, La Plata, Buenos Aires, Argentina.

Three patients underwent routine cataract surgery with bilateral implantation of one of three intraocular lenses: EyeDiff-R1 Add +3.50 (EyeOL, UK) (n=1), Alsafit Fourier Add +3.55 (Alsanza GmbH, Germany) (n=1), and Artis PL M Add +3.00 (Cristalens, France) (n=1). Each patient received the same IOL model in both eyes. Spherical refractive error and preoperative corneal astigmatism were corrected. Monocular and binocular distance-corrected visual acuity was measured at far, intermediate, and near distances using the Snellen chart. Defocus curves were analyzed based on the range of field (≥0.2 logMAR from 0.00 D to the minus range), visual acuity across distances, and binocular complementarity. All IOLs provided good vision across the tested range. The EyeDiff-R1 lens had higher monocular visual acuity peaks than the Alsafit Fourier but not the Artis PL M. Its monocular defocus range was 3.20 D, with a slight decrease to 0.15 logMAR at -1.00 D. Binocular defocus range was 3.40 D. The Alsafit Fourier lens had the lowest monocular visual performance. Its monocular defocus range was 2.60 D, with a decline to 0.15 logMAR between -1.00 and -1.50 D defocus, and a sharp drop at -2.00 D defocus. The binocular defocus range was 2.70 D. The Artis PL M had the best monocular performance, with a monocular defocus range of 3.30 D, without any remarkable decrease. The binocular defocus range was 3.50 D, showing the best binocular performance.

All three IOLs effectively restored vision at all examined distances, but the Artis PL M provided superior visual acuity, a wider range of vision, and better binocular summation, compared to its counterparts. Differences in defocus curve profiles may impact patient satisfaction and spectacle independence. The visual acuity declines with EyeDiff-R1 and Alsafit Fourier at specific defocus levels require further investigation. While all three lenses performed well, the Artis PL M demonstrated the most favourable outcomes. Larger studies are needed to confirm our findings and assess long-term performance.