Correlation Of Pupil Size With Visual Function After Implantation Of ReSTOR Apodized Diffractive Intraocular Lens

Background and PurposesNowadays, due to modern operation methods of phacoemulsification and technological advances in intraocular lens (IOL) design, cataract surgery has evolved from a sight-saving procedure to a refractive procedure.Multifocal IOLs were widely used in clinics.Recent studies reported the optical and visual performance of a multifocal IOL likely depends on pupil size. Today,one widely used refractive-diffractive multifocal IOL is the AcrySof ReSTOR (Alcon, Inc.).The objective of this study was to determine whether pupil size is correlated with visual acuity and contrast sensitivity in eyes with implantation of an Acrysof ReSTOR apodized diffractive intraocular lens (IOL).The aim of this study was to improve the visual outcomes of multifocal IOLs in clinics.MethodsThe prosective study comprised 63 patients having bilateral phacoemulsification surgery with implantation of an AcrySof ReSTOR SN60D3 IOL with a+4.0 D add power in the Department of Ophthalmlogy of the Second Affiliated Hospital of Zhengzhou University during December,2008 to October,2010. Patients were divided into 2 groups based on preoperative photopic pupil diameter:group A (2.0 to 3.5mm) and group B (3.6 to 6.0mm). Group A comprised 44 patients (88 eyes) and group B 19 patients (38 eyes). Three months postoperatively, monocular and binocular best corrected distance visual acuity(BCDVA) at 5m and monocular and binocular best corrected near visual acuity(BCNVA) at 33cm were measured. Monocular distance contrast sensitivity was measured by using Functional Visual Analyzer OPTEC 6500 at 1.5cpd,3cpd,6cpd,12cpd,18cpd spatial frequencies under 2 illuminatios:photopic (85 cd/m) and mesopic (5 cd/m2) conditions with or without glare.ResultsThree months postoperatively, pupil size is positively correlated with BCDVA (r=0.440, P<0.01),and negatively correlated with BCNVA(r=-0.365,P<0.01). There were statistically significant differences in monocular and binocular BCDVA between A group and B group (χ2=7.461, P<0.05;χ2=4.398, P<0.05),Group B had better BCDVA than group A. There was statistically significant differences in monocular BCNVA between group A and group B (χ2=10.006, P<0.05),Group A had better BCNVA than group B.However, There was no statistically significant differences in binocular BCNVA between group A and group B (χ2=0.154,P>0.05).Under photopic (85cd/m2) conditions with or without glare,there were statistically significant differences of contrast sensitivity at all spatial frequencies under three pupil conditions. When pupil diameter was 4-6mm,contrast sensitivity were statistically significantly higher than other two pupil size conditions.Under mesopic (5cd/m2) conditions with or without glare, when pupil diameter was 8mm,contrast sensitivity were statistically significantly lower than that when pupil size was 4-6mm.ConclusionsA larger pupil was correlated significantly with better monocular BCDVA and worse monocular BCNVA.With a larger pupil, patients with implantation of an AcrySof ReSTOR SN60D3 IOL had better monocular and binocular BCDVA and had worse monocular BCNVA.Binocular BCNVA was similar between two groups.Distansce contrast sensitivity was better with a larger pupil(4-6mm).