Analysis Of Microstructural Features Of Optic Disc In High Myopia

Objective:To investigate the correlation between the morphological characteristics of the high myopic disc and the blood flow density of radial peripapillary capillaries(RPC)and the thickness of the retinal nerve fiber layer(RNFL),and to lay the foundation for the prevention and treatment of high myopia.Methods:This study was a cross-sectional study;patients with high myopia who visited the ophthalmology department of the second hospital of JILIN University,from September 2020 to November 2022 were selected,119 cases with 175 eyes(56 of which were double and 63 of which were single),of which 35 cases with 51 eyes(16 double and 19 single)were male,accounting for 29.41% of the cases;84 cases with 124 eyes(40 double and 44 single)were female,accounting for 70.59% of the cases.The affected eyes were grouped according to ATN typing: 10 eyes in the nonpathological myopia group,115 eyes in the atrophic lesion group,21 eyes in the traction lesion group,and 29 eyes in the neovascular lesion group.Gender,age,eye type,IOP,best corrected visual acuity(BCVA),and spherical equivalent(SE)were recorded.All patients were examined using 45° fundus color photography,and the oval index(OI),rotation,and parapapillary atrophy(PPA)area of the optic disc were measured using Image J software.A 4.5 mm × 4.5 mm rectangular scan of the optic disc was performed using the "Angio-Disc" mode of the optical coherence tomography angiography(OCTA)system with enhanced high resolution,and a microvascular image of the RPC layer,choroid,and other layers was generated.Data were processed using IBM SPSS Statistics 26 software,and P <0.05 indicated that the differences were statistically significant.Results:1.The subgroups were statistically different(p < 0.05)in age,SE,OI,PPA area,RPC blood flow density,and peripapillary retinal nerve fiber layer thickness(p RNFLT)of the pars retina.2.Among all the subgroups,there were no significant differences in gender,the incidence of optical disc rotation,optic disc tilt,optical disc rotation,optic disc area,and disc rim area(P > 0.05).3.A comparison between groups was performed,and it was found that the differences in PPA area between the nonpathological myopia group and the atrophy group,the traction group,and the neovascularization group,respectively,were statistically significant(P < 0.05).4.The p RNFLT in the traction group was significantly lower than that in nonpathological myopia and atrophy groups,and the differences were statistically significant(P < 0.05).In the comparison of p RNFLT in different areas around the optic disc,the differences in p RNFLT between the nonpathological myopic group,the atrophy group,the traction group,and the neovascularization group were statistically significant(P < 0.05)in the lower half of the peripapillary disc,the lower nasal side,the lower temporal side,the upper temporal side,and the upper nasal side.There was no statistically significant difference in p RNFLT in the upper half of the disc perimeter,upper nasal side,lower nasal side,and upper temporal side(P >0.05).5.The differences between the nonpathological myopia group and the atrophy group,the nonpathological myopia group and the traction group,the nonpathological myopia group and the neovascularization group,and then the differences in peripapillary vessel density(PVD)between the nonpathological myopia group and the atrophy group,the nonpathological myopia group and the traction group,the nonpathological myopia group and the neovascularization group,and the atrophy group and the neovascularization group were all statistically significant(P < 0.05).In the comparison of PVD in different parts of the peri-disc,there were statistically significant differences in PVD between patients in nonpathological myopia,atrophy,traction,and neovascularization groups in the upper half of the peri-disc,the lower half of the peri-disc,above the nasal side,below the nasal side,below the temporal side,above the temporal side,above the temporal side,and the nasal side(P < 0.05).There was no statistically significant difference in PVD on the inferior nasal side(P > 0.05).6.Spearman’s correlation analysis of this study population revealed that p RNFLT was positively correlated with optic disc area(r=0.2918,P<0.05)and negatively correlated with PPA area(r=-0.2248,P=0.0205);PVD was negatively correlated with PPA area(r=-0.6406,P<0.05)and positively correlated with p RNFLT.The p RNFLT was negatively correlated with age(r=-0.3973,P<0.05),PVD was negatively correlated with age(r=-0.4183,P<0.05),optical disc rotation was positively correlated with age(r=0.1587,P<0.05);and PPA area was positively correlated with age(r=0.3140,P<0.05).Conclusions:1.Compared with the nonpathological high myopia population,the PPA area increased,the RPC blood flow density decreased,the RNFL thinned,the optic disc ellipticity ratio increased,and there was no significant difference in the degree of optic disc tilt and optical disc rotation in the population with tractive macular lesions.2.In the population with atrophic macular degeneration and neovascular macular degeneration,compared with the population with nonpathological high myopia,the PPA area increased,the RPC blood flow density decreased,and the RNFL thickness,optic disc tilt,and optical disc rotation were not significantly different.3.The PPA area was negatively correlated with RPC blood flow density and RNFL thickness,i.e.,the larger the PPA area,the lower the RPC blood flow density and the lower the RNFL thickness.Therefore,changes in the PPA area in highly myopic eyes should be closely monitored to prevent further progression of high myopia.