The Refraction Error And Its Influencing Factors After Phacoemulsification Of Primary Angle-Closure Glaucoma With Cataract

Objectives To investigate the refractive error and its influencing factors of patients with primary angle-closure glaucoma(PACG)with cataract after phacoemulsification combined with intraocular lens implantation(Phaco+IOL).To provide more ideas for reducing postoperative refractive error and improving visual quality in the future.Methods A retrospective study was designed.Patients who were diagnosed as PACG with cataract and age-related cataract and underwent Phaco+IOL at the North China University of Science and Technology affiliated Hospital,between November 2020 to May2021,were enrolled.They were divided into the PACG with cataract group and the simple cataract group.The eyes of all patients were evaluated by ancillary examinations,including visual acuity,the score of visual function index-14(VF-14),peripapillary retinal nerve fiber layer(p RNFL),axial length(AL),corneal curvature(K),anterior chamber depth(ACD),lens vault(LV)and so on.The SRK/T formula,Hoffer Q formula and Holladay 1formula were used to calculate the intraocular lens(IOL)power and the predicted spherical equivalent before surgery.The actual spherical equivalent was obtained by optometry after surgery.Wilcoxon rank sum test was used to evaluate the changes of best corrected visual acuity(BCVA)and the score of VF-14 before and after surgery in the two groups.Independent sample t-test was applied to compare the differences in AL,K,ACD,LV,p RNFL,mean refractive prediction error(ME)and mean absolute error(MAE)between the two groups.Analysis of variance was applied to compare the differences in MAE for each formula within the group.Chi-squared test was applied to compare the differences in the percentage of MAE within 0.50 D for each formula,and Pearson correlation analysis was applied to analyze the correlation between absolute error(AE)and AL,K,ACD and LV.Results 1 BCVA and the scores of VF-14: the level of BCVA and the scores of VF-14 after Phaco+IOL were significantly better than before surgery in both the simple cataract group and the PACG with cataract group(all P<0.05).2 Biological parameters of the eye:Compared with the simple cataract group,the PACG with cataract group had smaller AL and ACD(t=12.419,19.896,both P<0.05),and larger LV(t=-12.567,P<0.05).The difference in K between the two groups was not statistically significant(t=1.926,P>0.05).The PACG with cataract group had thinner superior p RNFL,inferior p RNFL,nasal p RNFL,temporal p RNFL,and mean p RNFL in each quadrant than the simple cataract group(t=5.665,10.238,3.239,2.617,7.272,all P<0.05).3 Refractive error: When the SRK/T formula,Hoffer Q formula and Holladay 1 formula were applied to predict postoperative refractive outcome,the difference in ME between the two groups was statistically significant(t=-8.146,-4.336,-6.149,all P<0.05),and the MAE in the PACG with cataract group was significantly larger than the MAE in the simple cataract(t=-4.719,-2.303,-3.656,all P<0.05).There was no significant difference in MAE among three formulas in the simple cataract group(F=0.660,P>0.05).In the PACG with cataract group,the Hoffer Q formula has the highest accuracy among the formulas.4 Correlation between AE and biological parameters of the eye: in the SRK/T formula,Hoffer Q formula and Holladay 1 formula,there was no significant correlation between AE and AL,ACD,LV and K in the simple cataract group(all P>0.05).However,AE in the PACG with cataract group was negatively correlated with AL and ACD(all P<0.05).AE was positively correlated with LV(all P<0.05),and AE was not significantly correlated with K(all P>0.05).Conclusions 1 The SRK/T formula,Hoffer Q formula,and Holladay 1 formula have similar accuracy in predicting IOL power in patients with age-related cataract,while the Hoffer Q formula is optimal in patients with PACG with cataract.2 Larger AE after Phaco+IOL in patients with PACG with cataract is related to preoperative shorter AL,shallower ACD,and higher LV.Refractive error is mostly hyperopia shift.Therefore,accurately measuring the biological parameters of the eye and increasing appropriately intended residual refractive power are beneficial to reduce its refractive error.Figure11;Table11;Reference 157...