Analysis Of Refractive Error And Preoperative Ocular Biometric Parameters In Glaucoma Patients After Phacotrabeculectomy

Objective:1.To study the refractive outcomes of primary acute angle-closure glaucoma(PAACG),primary chronic angle-closure glaucoma(PCACG),and primary open-angle glaucoma(POAG)patients 3 months after phacotrabeculectomy.2.To analyze the relationship between refractive outcomes and preoperative ocular biometric parameters.Methods:A retrospective clinical study.We included ninety patients(108 eyes)patients with glaucoma and co-existing cataract who performed phacotrabeculectomy at Shanxi eye hospital from February 2020 to February 2021,including 30(33 eyes)in PAACG,30(38eyes)in PCACG and 30(37 eyes)in POAG.Axial length(AL),central corneal thickness(CCT),keratometry,anterior chamber depth(ACD),lens thickness(LT)and WTW were measured by IOL Master 700,and the SRK-T formula of IOL Master 700 was used to calculated the intraocular lense power and predict refractive outcome.Subjective refraction was performed at 3 months.Compare the postoperative refractive error(RE)between PAACG,PCACG and POAG,analysis the correlation between RE and preoperative biometric parameters.The Barrett Universal II network formula was used to calculate the predicted postoperative refractive error and compare the two formulas with the difference in the predicted postoperative refractive error.Results :1.Refractive error: the mean refractive error of PAACG was(0.53 ± 0.75)D,include myopia error 5 eyes(15.2%),hyperopia error 18 eyes(54.5%),no refractive error10 eyes(30.3%).The mean refractive error of PCACG was(0.51 ± 0.70)D,include myopia error 8 eyes(21.1%),hyperopia error 19 eyes(50.0%),no refractive error 11 eyes(28.9%).The mean refractive error of POAG was(0.05 ± 0.47)D,include myopia error 9eyes(24.2%),hyperopia error 7 eyes(18.9%),no refractive error 21 eyes(56.8%).LSD:no refractive error between PAACG and PCACG(P=0.31),POAG and PAACG,POAG and PCACG refractive errors were significantly different(all P <0.05).2.Comparison of preoperative biological parameters of patients with PAACG,PCACG and POAG: Preoperative AL,ACD,LT between three groups are different(P<0.05);and no preoperative K,WTW and CCT values between the three groups(P>0.05).Through the LSD,preoperative AL,ACD and LT in the three groups were different(P <0.05),and there was no difference in preoperative K,WTW and CCT values between the three groups.3.Comparison of preoperative biological parameters between myopia and hyperopia groups: the preoperative AL of the hyperopia group was longer than that of myopia group,the preoperative ACD was shallower than that of myopia group,and the LT was thicker than that of myopia group,the difference was statistically significant(t=4.86,P =0.00;t=3.48,P =0.00;t=-3.75,P =0.00).For the CCT,K and WTW,there was no significant difference between the two group(t=0.83,P=0.41;t=-0.42,P=0.67;t=-0.85,P=0.39).4.Comparison of the postoperative refractive error predicted by the SRK-T and Barrett Universal II formulas: the refractive error predicted by the two formulas is not significantly different(P> 0.05).Through the Bland-Altman diagram,most of the data are distributed in the 95% interval(within 1.96 standard deviations),indicating that the two formulas predict postoperative refractive error to agree well.5.Correlation analysis between RE and preoperative biological parameters: there was negative correlation of RE and preoperative AL,ACD(r=-0.62,P<0.05;r=-0.48,P<0.05)and positive correlation was observed with the LT(r=0.538,P<0.05),there was no significant correlation between postoperative RE and the CCT,keratometry,WTW(P> 0.05).In this regression model(R2=0.472,F=11.063,P=0.00),preoperative AL(=-0.676,P=0.000),preoperative ACD(=0.325,P=0.044),preoperative LT(=0.357,P=0.001)were the factors affecting postoperative refractive error,preoperative IOP,age,preoperative CCT,preoperative K,and preoperative WTW in the regression model(both P> 0.05).Conclusion:1.Using the SRK-T formulas to predict the post-operative refraction,compared with POAG patients,PAACG and PCACG patients showed more refractive error,and mostly hyperopic RE.2.In addiction the shorter preoperative AL,shallower ACD and thicker LT were,the refractive out after phacotrabeculectomy are more likely to have hyperopia.