Clinical Study On The Relationship Between Parapapillary Atrophy Of Myopia And Primary Open Angle Glaucoma

Objective:To study the characteristics of parapapillary atrophy（PPA）in myopic patients and myopic patients with primary open angle glaucoma（POAG）,and to explore whether the quantification of PPA subsets based on optical coherence tomography（OCT）can improve the diagnosis of POAG in myopic patients and the correlation between myopia,PPA and POAG.Methods:From September 2020 to November 2021,the clinical data of myopia patients with POAG（experimental group）and myopia patients（control group）aged from 18 to 50 years old who were treated in the ophthalmology clinic of our hospital were analyzed,the optic disc parameters to be measured in both groups include optic disc tilt,PPA width and PPA edge irregularity index.Use SPSS 26.0 to analyze all the data statistically.The measurement data are expressed as mean ±standard deviation.The normality test was carried out for the measurement data,T-test was used for the difference of measurement data between the two groups,and Mann Whitney U test was used for the difference of those who did not conform to the normal distribution.Multiple linear regression was used to determine the correlation between PPA parameters and age,sex,intraocular pressure,refractive error and POAG.The value of P < 0.05 was statistically significant.Results:1.In this study,22 patients（37 eyes）with myopia complicated with POAG and23 patients（42 eyes）with myopia were included.Compared with the control group,the width of total PPA in the case group was smaller and the intraocular pressure（IOP）was larger,and there was significant difference between the two groups（P=0.029;P<0.001）.The marginal irregularity index of PPA in the case group was larger,and the width of γ-PPA in the control group was larger.The difference between the two groups was statistically significant（P=0.082;P=0.094）.2.After adjusting sex,age and spherical equivalent refraction（SE）,there was a statistical correlation between total PPA width and POAG.3.β-PPA width was significantly correlated with sex,age and SE;γ-PPA width was significantly correlated with PPA edge irregularity index and optic disc slope;total PPA width was significantly correlated with SE,PPA edge irregularity index,optic disc slope and POAG,while PPA edge irregularity index was only significantly correlated with γ-PPA width.4.In the case group,the mean deviation（MD）and pattern standard deviation（PSD）of visual field（VF）were not significantly correlated with any factors.Conclusion:1.β-PPA and γ-PPA defined morphologically by OCT are not helpful to distinguish myopic POAG patients from myopic patients,while the total PPA width may be an indicator of POAG risk screening for myopic patients in the future.In the case of large sample size,the differences of some parameters may be statistically significant,but the clinical practicability of the statistically significant differences of these parameters remains to be further discussed.2.Larger total PPA may be a risk factor for POAG in myopic patients.3.There was a correlation between β-PPA width and γ-PPA width and different independent variables,but there was no correlation between them.It is speculated that the formation of β-PPA width and γ-PPA width may be the result of different physiological mechanisms.4.This study introduced a method to quantify and compare the degree of PPA edge irregularity（i.e.PPA edge irregularity index）,which was significantly correlated with the width of γ-PPA.The irregular edge of PPA may be due to the fact that γ-PPA has neither Bruch membrane nor retinal pigment epitheliumon（RPE）the exposed sclera.The absence of these normal components in a larger range may affect the biomechanics of the periphery of the optic disc and make it prone to irregular deformation.5.In this study,we did not find that the related parameters of PPA can be used as an index to judge the severity of POAG in patients with myopia.