Abstract
Purpose: :
To compare quality of vision in pseudophakic patients implanted either with an aspherical intraocular lens (IOL) or with a conventional spherical IOL.
Methods: :
In this prospective case–control study, twenty patients were randomly divided in two equal groups to receive either the prolate aspherical Tecnis Z9000 IOL (AMO, USA) or the spherical CeeOn Edge 911 IOL (AMO, USA). Contrast sensitivity was measured pre– and 2–months post–surgery under photopic, mesopic and glare conditions. Other postoperative examinations included refractive evaluation before and after mydriasis, pupils diameter and wavefront aberration analysis. Patients bilaterally operated (5 in each group) filled a questionnaire to evaluate the performance of each IOL (Activities of Daily Vision Scale).
Results: :
Postoperative best–corrected visual acuity was 0.94±0.12 (mean ± SD) for the Tecnis group versus 0.97±0.08 for the CeeOn Edge 911 group (P=0.79). Refractive evaluation revealed a myopic shift with mydriasis as low as –0.02±0.35 D in patients implanted with the Tecnis IOL compared to –0.63±0.19 D in the CeeOn Edge 911 group (P=0.001). Mesopic contrast sensitivity was significantly improved in the Tecnis group at medium (p=0.013) and high spatial frequencies (P=0.008), while contrast sensitivity under photopic and glare conditions was similar between the two groups. Spherical aberration was significantly lower in patients with the Tecnis IOL as compared to the CeeOn Edge 911 group (Z40 = 0.01±0.06 µm vs 0.16±0.13 µm, respectively, P=0.001). Global score of ADVS was improved in Tecnis group but did not reach significance (P=0.08).
Conclusions: :
Combining contrast sensitivity and wavefront aberration analysis allowed an objective assessment of the quality of vision in pseudophakic patients. Our data reinforce previous studies suggesting that the implantation of an aspherical IOL with a prolate anterior surface results in reduced spherical aberration and improved contrast sensitivity under mesopic conditions.
Keywords: intraocular lens • optical properties • cataract