A Quantitative Study Of Macular Vascular Density Change In Primary Angle Closure Glaucoma

Purpose :The parameters of blood vessels in macular region in primary angle closure(PAC),primary angle closure glaucoma(PACG)and healthy individuals were investigated using optical coherence tomography angiography(OCTA)and the diagnostic value of each parameter for PACG was analysed.Methods:This was a comprehensive cross-sectional study which aimed to investigate the blood flow parameters in different macular regions of patients with primary angle-closure glaucoma(PACG).The study was conducted at the Eye Hospital of Nanchang University and included patients who attended the hospital from October 1,2019 to December 28,2022 and met the enrollment criteria.The participants comprised of 27 patients with 33 eyes in the PAC group,45 patients with 51 eyes in the PACG group,and 30 healthy individuals with 30 eyes as the control group,during the same period.Ophthalmic routine examinations such as IOP measurement,comprehensive optometry,frequency domain optical coherence tomography,and Humphrey computerized visual field were performed in all three groups,respectively.Blood flow parameters in the central,inner,outer,and overall macular regions were measured by OCTA in the three groups.SPSS 25.0 statistical software was applied to analyze whether there was a statistical difference between the parameters of the three groups.The diagnostic value of each parameter for PACG was assessed using the area under the receiver operating characteristic curve(AUROC).Results:There was no statistical difference in age and gender composition between the three groups(all P > 0.05).There was a difference in IOP comparison between the three groups(P < 0.001),with statistically significant differences in IOP between the control and PAC groups and the PACG group(all P < 0.001),and no statistically significant differences in IOP between the PAC and control groups(P > 0.999).The differences in BCVA between the different subgroups were all statistically significant(P = 0.007,<0.001,<0.001).The differences in MD values,RNFL thickness,mean and minimum GCIPL thickness were statistically significant between the control and PAC groups and PACG groups(all P < 0.001),and the differences in MD values,RNFL thickness,mean and minimum GCIPL thickness between the PAC and control groups were not statistically significant(P = 0.547,> 0.999,0.313,0.441).In the central zone,inner zone,outer zone,and overall zone,there was a statistically significant difference in VD between the PACG group and the control group(all P<0.001),and a statistically significant difference in VD between the PAC group and the control group(P=0.003,0.03,0.023,and 0.017).In the inner zone,outer zone,and overall zone,the differences in VD between the PACG and PAC groups were statistically significant(P=0.016,<0.001,<0.001).In the central zone,there was no statistically significant difference in VD comparison between the PACG and PAC groups(P=0.108).In the inner zone,outer zone,and overall zone,the differences in PD between the PAC and control groups,the PACG and control groups,and the PAC and PACG groups were statistically significant(all P < 0.05).In the central zone,the difference in PD between the PACG and control groups was statistically significant(P= 0.007),and the difference in PD between the PAC and PACG groups and control groups was not statistically significant(P = 0.071,> 0.999).ROC curve analysis showed that in identifying the control and PACG groups,where the maximum value of AUROC for the minimum GCIPL thickness was 0.980(P < 0.001)and the maximum value of AUROC for VD in the outer macular region was 0.946(P < 0.001).In the discriminating control and PAC groups,the maximum value of AUROC for mean GCIPL thickness was 0.708(P=0.005)and the maximum value of AUROC for VD in the outer macular region was 0.831(P<0.001).Conclusion:Macular blood flow density in the PACG group was reduced compared to the PAC group and the control group.The blood flow density in both the inner and outer regions of the PAC group was reduced compared to the control group,and the diagnostic power of VD and GCIPL thickness in the outer region of the macula was comparable.