Effect of decentration on the quality of vision: comparison between aspheric balance curve design and posterior aspheric design intraocular lenses.

Abstract

To study the effect of decentration on the quality of vision in 2 aspheric intraocular lenses (IOLs): aspheric balance curve (ABC) design Vivinex iSert XY1 (Hoya Surgical Opticals, Inc.) and posterior aspheric design AcrySof IQ SN60WF (Alcon Laboratories, Inc.). Advanced Eye Centre, PGIMER, Chandigarh, India. Randomized prospective trial using a random number table. 85 eyes were randomized to group 1 (Vivinex XY1) and group 2 (AcrySof IQ) with 40 and 45 eyes, respectively. The higher-order aberration (HOA) profile, Strehl ratio, decentration of the IOL from the visual axis (decentration from the visual axis [DVA]) and the geometric axis (decentration from the geometric axis [DGA]), angle α, and κ were recorded on the iTrace aberrometer, and contrast sensitivity was measured using the Functional Acuity Contrast Test at 12 weeks postsurgery. A total of 85 eyes in 60 patients were evaluated in this study. The mean values of the Strehl ratio (P = .48) and the HOAs (P = .12) of both IOLs were comparable. The HOAs gradually increased with increasing DVA for both lenses at 3.0 mm, 4.0 mm, and 5.0 mm pupil sizes. On comparing the HOAs with the DGA, a statistically insignificant positive correlation was observed. The Strehl ratio did not deteriorate with an increasing angle α in the Vivinex XY1 group; however, it worsened in the AcrySof IQ group. Contrast sensitivity was comparable in both the IOLs except at 1.5 cycles per degree under photopic conditions where the AcrySof IQ was better. Decentration of the lens was best measured with respect to the visual axis. In eyes with a large α, the ABC design induced lesser HOAs and maintained a better Strehl ratio.