Clinical study of visual performance in patients with bilateral implantation of apodized diffractive aspheric multifocal intraocular lenses

Abstract

Objective To evaluate visual performance after bilateral implantation with either the AcrySof ReSTOR SN6AD1 multifocal intraocular lens (MIOL) or the AcrySof ReSTOR SN6AD3 MIOL. Methods This was a prospective case series study. Sixty age-related cataract patients (120eyes) at the Zhongshan Ophthalmic Center from June 2009 to April 2010 were enrolled in this study.Based on the principal of voluntary choice, phacoemulsification combined with IOL implantation was performed. There were 20 patients (40 eyes) in each group, the SN6AD1 MIOL group, SN6AD3MIOL group and SN60WF group. There were 8 male patients and 12 female patients (8/12) in the SN6AD1 group, and 10/10 and 11/9 in the SN6AD3 and SN60WF groups, respectively. The average ages in years were 64.6±12.7, 67.5±8.5, and 61.1±11.0, respectively. Uncorrected near visual acuity (UCNVA), uncorrected intermediate visual acuity (UCIVA) under high and low contrast conditions,uncorrected distance visual acuity (UCDVA), uncorrected near visual acuity for Chinese characters under high and low contrasts, contrast sensitivity, preferred reading distance and reading speeds were assessed 3 months postoperatively. A one-way ANOVA, Bonferroni, rank-sum test or independent samples t test was used to analyze the data. Results UCNVA was (0.074±0.862)logMAR for the SN6AD1 group and was (0.075±0.772)logMAR for the SN6AD3 group, which was significantly better than the (0.351±0.691)logMAR for the SN60WF group (Z=-6.756, P=0.000; Z=-6.508, P=0.000).Significant differences were found for UCIVA at 40 cm under either high or low contrast conditions when the 3 groups were compared (high contrast: x2=29.085, P=0.000; low contrast: F=9.672, P=0.000). UCIVA was also significantly different at 63 cm under either high or low contrast conditions when the 3 groups were compared (high contrast: x2=14.869, P=0.001; low contrast: x2=8.018, P=0.018). There were no significant differences in UCDVA among the 3 groups (x2=1.555, P=0.460).Monocular and binocular uncorrected near vision for Chinese characters was significantly better for the SN6AD1 and SN6AD3 groups than for the SN60WF group, but there were no significant differences for Chinese characters with fewer strokes viewed under low contrast conditions (P＞0.05). Compared to the SN60WF group, contrast sensitivity under intermediate or low spatial frequencies was lower for both the SN6AD1 and SN6AD3 groups (P＜0.05). The preferred reading distances were (38.5±3.1)cm,(32.8±3.9)cm, and (47.6±4.7)cm, respectively. Reading speeds of the SN6AD1 and SN6AD3 groups were faster than that of the SN60WF group(P＜0.05). Conclusion UCNVA and UCIVA at 40 cm and 63 cm, preferred reading distance and reading speed are better for the SN6AD1 and SN6AD3MIOL SN6AD1 MIOL provide better UCIVA at 40 cm and 63 cm under high and low contrast conditions than SN6AD3 MIOL. Key words: Lenses,intraocular,multifocal; Visual acuity; Contrast sensitivity; Reading speed; Phacoemulsification