Purpose: To compare visual function in pseudophakic patients with bilateral implantation of Tecnis multifocal aspheric and conventional monofocal spherical intraocular lenses (IOL).
Methods: A prospective study of 100 consecutive cases (200 eyes) was conducted. All cataract patients underwent phacoemulsification were randomized to receive multifocal aspheric IOL (Tecnis ZM900, AMO, multifocal aspheric group) or conventional spherical IOL (Akreos Adapt, Bausch & Lomb, monofocal spherical group). The following investigations were performed to assess the uncorrected and distance-corrected visual acuity of distance, intermediate and near distances, accommodative amplitude, spherical aberrations of total eye, contrast sensitivity, glare sensitivity and near stereoacuity. Patients were surveyed for visual disturbances and lifestyle visual quality. The independent-samples t test was used to compare the measure data which met normal distribution and the Mann-Whitney U test was used to compare the measure data which didn't meet. The chi-square test was applied to compare categorical variables.
Results: The uncorrected and distance-corrected bilateral visual acuity of multifocal aspheric group at 30 cm and 40 cm were 0.24 ± 0.12 and 0.22 ± 0.11 (logMAR), better than monofocal spherical group (Z = -8.261, P = 0.000; Z = -5.508, P = 0.000), but the visual acuity at other distances had no statistical difference between two groups. Patients with multifocal aspheric IOL had significantly higher accommodative amplitude than those with monofocal spherical IOL, improved about 2.3 ∼ 2.8 D (Z = -10.655, P = 0.000; Z = -2.709, P = 0.007). Mean spherical aberration of multifocal aspheric group was (0.027 ± 0.160) µm and (0.006 ± 0.083) µm, significantly lower than that of monofocal spherical group (0.269 ± 0.161) µm, (0.037 ± 0.205) µm at 5 mm and 3 mm pupil diameter (Z = -8.815, P = 0.000; Z = -2.791, P = 0.005). The difference of contrast sensitivity was not significant, but glare sensitivity was higher for monofocal spherical group than for multifocal aspheric group. Multifocal aspheric group showed statistically better uncorrected stereoacuity (72.4 ± 29.9)″ than monofocal spherical group (92.8 ± 35.7)″ (Z = -3.089, P = 0.002).
Conclusions: The present clinical results demonstrated that Tecnis multifocal aspheric group had better near visual acuity, accommodative amplitude and near stereoacuity as compared to conventional monofocal spherical group. The aspheric design reduced spherical aberration of total eye and improved contrast sensitivity in some way.