A Study Of The Morphological Characteristics Of The Tilted Opticdisc And Its Refractive State In Children

Objective（s）:To assess the prevalence of optic disc tilt in children with refractive errors,to observe the morphological characteristics of optic disc tilt,to describe and analyze the ocular parameters affecting optic disc tilt,and to investigate the correlation between optic disc tilt and refractive error.Methods:Retrospective studies.Between July 1,2022 and July 30,2022,a total of 3,290 children received posterior pole fundus photography at the ophthalmology clinic of Kunming Children’s Hospital.According to stereoscopic photographs and the interpretation of the tilt of the optic disc through Image J software,210（6.38%）children with tilted optic disc were found.Excluding 72 children who did not undergo ocular biometric examination,138 children were eventually enrolled in the optic disc tilt group of this study,with a total of 224 eyes.All participants were measured for eye parameters such as naked-eye visual acuity,best-corrected visual acuity,optometry,axial length,radius of corneal curvature,corneal astigmatism,etc.The posterior pole fundus photographic camera was used to scan the fundus color image,and the image J software was used to identify and interpret the boundary of the scanned image,and the ovality index（OI）of the optic disc was calculated by using the maximum diameter ratio of the minimum diameter of the optic disc.An OI≥1.33 combined with expert opinion was used as the diagnostic criterion for optic disc tilt.An independent statistical member performed the subject matching procedure and randomly recruited children without optic disc tilt（OI<1.33）whose age and sex matched those in the optic disc tilt group to form a control group of 112 subjects each,with a total of 224 eyes.Explore the differences in optic disc morphology and ocular parameters between the two groups.Through statistical analysis,whether ocular biological parameters such as AL,SE,corneal astigmatism,and corneal curvature radius were the influencing factors of optic disc tilt,and the correlation between optic disc tilt and refractive error was analyzed.Results:A total of 138 subjects in the optic disc tilt group were included,with a total of 224 optic disc tilt eyes,with an average age of 9.54±2.90 years,including 77males（55.80%）,61 females（44.20%）,52 children（37.68%）in monocular and 86children（62.32%）in both eyes.There were no differences in sex,age or eye distinction between the optic disc tilt group and the control group（P>0.05）.The most common morphological features were paracapillary atrophy（61.61%）,leopard striate changes in 99 eyes（44.20%）,and blood vessel reversal in 41 eyes（18.30%）.The most common tilt direction was the lateral temporal（69.64%）,followed by supratemporal（21.88%）,subtemporal（7.59%）,and nasal（0.89%）.The paracapillary atrophy is mainly located on the temporal side and corresponds to the most common direction of optic disc tilt.The analysis of the parameters related to the morphology of the optic disc showed that there was a statistically significant difference between the horizontal diameter and vertical diameter of the two groups（P<0.05）,and the horizontal diameter of the optic disc in the optic disc tilt group was significantly smaller than that in the control group（P<0.0001）,the vertical diameter of the optic disc was greater than that of the control group（P=0.006）.Myopia appeared in 110 eyes（49.1%）in the optic disc tilt group,which was significantly higher than that in the control group(47 eyes（20.98%）,and there was a significant difference in the prevalence of myopia between the two groups（P<0.0001）.When subdivided into low,moderate and high myopia,only the difference between the two groups was statistically significant between the two groups between low（P=0.0007）and moderate（P<0.0001）.The prevalence of astigmatism in the optic disc tilt group（59.38%）was also higher than in the control group（42.86%）,and there was a difference in the prevalence of astigmatism between the two groups（P=0.0007）.Compared with the control group,the average equivalent spherical lens degree（t=-6.220,p<0.0001）,eye axis length（t=9.145,p<0.0001）,axial ratio（t=6.862,p<0.0001）,astigmatism（t=2.076,p=0.038）,corneal astigmatism（t=2.748,p=0.0006）,K₂（t=-2.409,p=0.016）were statistically significant.Among them,OI was significantly positively correlated with AL（r=0.4305,P<0.0001）,significantly negative with SE（r=-0.4114,P<0.0001）,significantly positively correlated with axial ratio（r=0.4188,P<0.0001）,negatively correlated with astigmatism（r=-0.256,P<0.0001）,positively correlated with corneal astigmatism（r=0.1114,P=0.0184）,and K2（r=-0.2125,P<0.0001）.Conclusion（s）:1.Optic disc tilt is a common change in the shape of the optic disc in children with refractive error,Prevalence of optic disc tilt in children at Kunming Children’s Hospital was 6.38%in July 2022.2.Optic discs in eyes with tilted discs have smaller horizontal diameters compared to normal discs.3.Eyes with tilted optic discs have higher myopia,astigmatism,axial length and axial ratio than eyes with normal optic discs.4.Optic disc tilted eyes are often associated with myopia and astigmatism.5.The greater the ovality of the optic disc,the greater the degree of myopia and astigmatism,and the longer the axis of the eye.