Comparison of contrast sensitivity, depth of field and ocular wavefront aberrations in eyes with an IOL with zero versus positive spherical aberration.

Purpose: To compare the clinical performance of the zero spherical aberration (SA) SofPort LI61AO (AO, Bausch & Lomb) intraocular lens (IOL) to the AcrySof SA60AT (AT, Alcon), which has positive spherical aberration.

Methods: Patients underwent uneventful phacoemulsification with implantation of either an aspheric (AO, n = 19) or spherical (AT, n = 20) IOL. Postoperatively, a 5 mm artificial pupil was positioned in trial frames with the cycloplegic refraction during monocular, mesopic contrast sensitivity (CSF) and low-contrast visual acuity (LCVA) testing with glare. Ocular and corneal wavefront error was determined at 5 mm diameters.

Results: Mean CSF scores were better at all frequencies tested for the AO than for the AT group, and achieved statistical significance at 1.5 cpd (p = 0.038) and 6 cpd (p = 0.017). With glare, AO eyes read 30.9 +/- 5.0 low-contrast letters versus 25.2 +/- 6.8 for AT eyes (p = 0.005) (mean DeltaLogMAR = -0.10), while high-contrast acuity and refraction were similar. Eyes implanted with the SA60AT had 43% greater positive spherical aberration at a 5 mm wavefront diameter, with no significant difference in corneal SA between groups. A through-focus analysis demonstrated a similar depth of field, yet a comparatively higher visual Strehl ratio for the aspheric IOL at emmetropia (p = 0.038).

Conclusion: Eyes with the SofPort Advance Optics neutral aberration IOL demonstrated less spherical aberration and better low-contrast acuity compared to eyes with a spherical IOL, without sacrificing tolerance to defocus. The aspheric IOL showed superior optical and clinical performance, which is most likely due to its surface design.