Posters

Visual response to multifocal spherical correction

Poster Details

First Author: I.Siso-Fuertes UK

Co Author(s):    R. Montes-Mico   J. Alfonso   H. Radhakrishnan              

Abstract Details

Purpose:

To assess the visual acuity and ocular aberrations with multifocal spherical correction and to address the effect of pupil size on aberration outcomes.

Setting:

Optometry Research Group (GIO), Optics department, University of Valencia, Spain.

Methods:

Fifteen eyes from young patients with astigmatism under 0.75 D were fitted in random order with two different multifocal contact lenses (CLs) differing in transition zone design. CLs used had a centre-near design analogous to that of multifocal intraocular lenses (IOLs). Corrected distance visual acuity (CDVA) and distance corrected near visual acuity (DCNVA) were measured and aberrations were assessed. Hartmann-Shack based equipment incorporated in the crx1 Adaptive Optics Visual Simulator (Imagine Eyes) was used. Equivalent defocus, fourth-order spherical aberration and third-order coma aberration data were rescaled and compared for a fixed pupil diameter of 4 mm and for natural conditions.

Results:

Both multifocal spherical lenses used in this study provided good visual acuity at both distances (CDVA: 0.04 ± 0.03 and 0.01 ± 0.03; DCNVA: 0.14 ± 0.03 and 0.06 ± 0.03 for the narrower and wider transition zones respectively). Equivalent dioptric values for aberrations, that allow direct comparison of results at different pupil diameters, were statistically significantly different (p<0.05) for a 4 mm fixed diameter and for natural pupil size. These findings were consistent for defocus, fourth-order spherical aberration and third-order coma for both lenses.

Conclusions:

Optical quality is usually characterized for fixed pupil diameters. Results obtained in this study from aberration data with multifocal lens designs on eye show that wavefront analysis should be treated carefully; intrapolating or extrapolating the aberrations for an alternative pupil size could lead to significant differences in understanding the impact of aberrations from what is seen from natural pupil size.

Financial Disclosure:

NONE