The Role Of Angle Kappa In Visual Quality In Patients With Trifocal Diffractive Intraocular Lens

Purpose: To evaluate the visual quality of the patients with different angle kappa after a trifocal diffractive intraocular Lens implantation.Methods:This was a retrospective study enrolling 89 eyes of 89 patients who had phacoemulsification with implantation of trifocal IOL AT LISA tri 839 MP.According to the size of preoperative angle kappa,the patients were divided into three groups: group A(0 <r?0.2mm)29 cases(29 eyes);group B(0.2mm <r?0.4mm)33 cases(33 eyes)Group C(r>0.4mm)in 27 cases(27 eyes).Monocular uncorrected visual acuities were measured at distance(5m),intermediate(60cm),and near(35cm)during a 3-month follow-up.Other outcome measurements were modulation transfer function cut off frequency(MTF cutoff),Strehl ratio,OQAS values(OVs)at contrasts of 100%,20% and9%,and objective scatter index(OSI).All patients also completed a subjective questionnaire survey,including surgical satisfaction,spectacle independence,perception of photic phenomena.Visual acuity,OQAS parameter results were compared using one-way ANOVA and LSD test.In all cases,a p-value <0.05 was considered statistically signifcant.The chi-square test was used to assess differences in categorical variables.Results:The incidence of glare and halo was different in 3 months after operation,the difference was statistically significant(P<0.05).There were no statistical significances in three groups after surgery in the followingvariables: UDVA,UIVA,UNVA,MTF cut off,SR and spectacle independence(P> 0.05).The difference of MTF cutoff and SR between the angle kappa max and the minimum interval was statistically significant(P<0.05).A great majority of patients were satisfied with the operation.Conclusion:Angle kappa may not affect patients' postoperative far,intermediate,and near vision,and in a certain range doesn't affect the patient's visual quality.However,when the angle kappa at a certain level will affect the visual quality of patients after surgery,this study found that angle kappa greater than 0.5mm,the patients' visual quality decreased,glare,halo and other adverse symptoms increased,the difference was statistically significant,but the sample size is small,still need more follow-up clinical data support.In clinical work,for patients with larger kappa angle,choosed to implant trifocal intraocular lens should be careful.