A Study On Long Term Contrast Sensitivity Of Multifocal Intraocular Lens Implantation.

Objective: Comparing the long term visual acuity,contrast sensitivity and visual symptoms of the multifocal intraocular lenses (MIOL) eyes with monofocal intraocular lenses (SIOL)eyes to evaluate the safety and effectiveness of the MIOL. Methods: 33 cases 50 eyes of MIOL implantation were enrolled at investigational sites. 28 cases 43 eyes of SIOL implantation were enrolled in a control substudy.All the cases were performed the cataract phacoemusification and intraocular lenses implantation surgery.All the patients were more than 6 months post operation.Average times was 18.26±10.16 months in investigational sites and 20.56±12.30 months in control sites.Patients were examined at random about uncorrected distant visual acuty,best corrected distant visual acuty,uncorrected near visual acuty,best corrected near visual acuty, distance corrected near visual acuty, contrast sensitivity in the near-corrected,and visual symptoms were observed by questionnaire. Results: There was no significant difference about uncorrected distant vision, best corrected distant vision and best corrected near vision between two groups. There were 41 eyes(82.00%)in MIOL group have uncorrected near vision better than 0.5,and control group only have 6 eyes (13.95%),difference has significance(P<0.05). MIOL group has better distance corrected near visual acuty than control group.MIOL group have 46 eyes(92.00%)better than 0.5,and SIOL group only have 13 eyes(30.23%),difference has Significance.Contrast sensitivity in the two groups were in the normal range, and did not differ from each other. The contrast sensitivity of vision worser than 1.0 was lower than that's of the vision better than 1.0,and there is statistics significance in 6.0CPD,12CPD,18CPD in the MIOL group,and 18CPD in the control group. In the study group, when astigmatism was 0.5 diopters or more, contrast sensitivity was worse than that's astigmatism not reach to 0.5 diopiters in 3.0CPD,6.0CPD,12CPD,18CPD.In the control group,astigmatism has influence on the contrast sensitivity only in 18 CPD. Five cases 6 eyes of investigational sites and 1 case 1 eye of control group reported Halo,but the majority not being bothered by these at all. Conclusion:MIOL has better near visual acuity than SIOL group,and distance visual acuity in gear.Long term contrast sensitivity of MIOL implantation was in the normal rage,but easy to be influenced by astigmatism and best corrected near vision.MIOL is safety and effectiveness.