Stability Of Intraocular Lens In The Capsule And Its Effect On Postoperative Refractive Status In Primary Angle Closure Glaucoma Patients

Objective:To evaluate the stability of intraocular lens(IOL)in the capsule at the early stage on primary angle closure glaucoma patients after phacoemulsification combined with intraocular lens implantation combined with goniosynechialysis.To analyse the correlation between the tilt and decentration of IOL and surgicallyinduced astigmatism induced by IOL(SIAIOL)as well as absolute refractive prediction error(ARPE).Methods:Cross-sectional study.The glaucoma & cataract group consisted of primary angle closure glaucoma patients who underwent phacoemulsification combined with intraocular lens implantation combined with goniosynechialysis while the control group consisted of age,sex and axial length matched age-related cataract patients who underwent phacoemulsification combined with intraocular lens implantation in our hospital from May 2021 to November 2021.All patients undergone the examinations including visual acuity,intraocular pressure,computer automatic optometry,slit-lamp biomicroscop and fundus examination,tilt and decentration of IOL and corneal topography measured by IOL scan mode and corneal analysis mode of CASIA2(CASIA2,TOMEY,Nagoya,Japan)respectively one month after surgery.Using astigmatism vector analysis software(Vertr AKTM)to calculate the vector difference between the total astigmatism measured by automatic computer optometer and real corneal astigmatism measured by the corneal analysis mode of CASIA2,which is defined as surgically-induced astigmatism induced by IOL(SIAIOL).Tilt and decentration of IOL,surgically-induced astigmatism induced by IOL(SIAIOL)and refractive prediction error(RPE)between two groups was compared.The correlation between the tilt and decentration of IOL and surgically-induced astigmatism induced by IOL(SIAIOL)as well as absolute refractive prediction error(ARPE)was analysed by correlation and regression.P<0.05 was considered as statistical significance.Results:94 eyes of 94 patients were included,including 58 eyes of 58 patients in the glaucoma & cataract group and 36 eyes of 36 patients in the cataract group.Mean tilt of IOL in the glaucoma & cataract group was 5.83±1.72°(ranged from 2.3°to 9.5°)while mean tilt of IOL in the cataract group was 5.79±1.32°(ranged from 3.1°to 8.2°).There was no significant difference between two groups in tilt of IOL(P=0.917).Mean decentration of IOL in the glaucoma & cataract group was 0.19±0.09mm(ranged from 0.04 mm to 0.45 mm)while Mean decentration of IOL in the cataract group was 0.17±0.09mm(ranged from 0.01 mm to 0.36 mm).There was no significant difference between two groups in decentration of IOL(P=0.227).Surgically-induced astigmatism induced by IOL(SIAIOL)in the glaucoma & cataract group ranged from 0.13 D to 2.62 D and M(P25,P75)was 0.81(0.54,1.13)D while surgically-induced astigmatism induced by IOL(SIAIOL)in the cataract group ranged from 0.02 D to 2.66 D and M(P25,P75)was 0.65(0.44,1.22)D.There was no significant difference between two groups in surgicallyinduced astigmatism induced by IOL(SIAIOL)(P=0.491).Refractive prediction error(RPE)in the glaucoma & cataract group ranged from-1.93 D to 1.07 D and mean error(ME)was-0.38±0.60 D,mean absolute error(MAE)was 0.61±0.45 D,median absolute error(Med AE)was 0.51 D while refractive prediction error(RPE)in the cataract group ranged from-1.66 D to 0.83 D and mean error(ME)was-0.17±0.54 D,mean absolute error(MAE)was 0.45±0.30 D,median absolute error(Med AE)was 0.43 D.There were no significant differences between two groups in mean error(ME),mean absolute error(MAE)and median absolute error(Med AE)(P=0.104,P=0.096,P=0.117).In both groups the effect of tilt of IOL on surgically-induced astigmatism induced by IOL(SIAIOL)was statistically significant(glaucoma & cataract group:B=0.107,R2=0.092,P=0.021;cataract group:B=0.322,R2=0.429,P<0.001).SIAIOL was positively correlated with tilt of IOL.Conclusions:There were similar good stability of intraocular lens(IOL)in the capsule as well as mild surgically-induced astigmatism induced by IOL(SIAIOL)and refractive prediction error(RPE)between primary angle closure glaucoma patients and age-related cataract patients at the early stage postoperatively.There was positive correlation between tilt of IOL and surgically-induced astigmatism induced by IOL(SIAIOL)in both primary angle closure glaucoma patients and age-related cataract patients at the early stage postoperatively.