Comparison of localized retinal nerve fiber layer defects in highly myopic, myopic, and non-myopic patients with normal-tension glaucoma: a retrospective cross-sectional study

Abstract

BackgroundThe purpose of this study was to evaluate the relationship between patterns of localized retinal nerve fiber layer (RNFL) defects and the degree of myopia in patients with normal-tension glaucoma (NTG).MethodsWe retrospectively reviewed medical records of patients with high myopia (42 eyes; spherical equivalent [SE] < −6.0 diopters [D]), low to moderate myopia (93 eyes; SE −6.0D ~ and −0.5D), and emmetropia (65 eyes; SE −0.5D ~ +0.5D), all of which were diagnosed as having NTG with localized RNFL defects. On RNFL photographs, the proximity of the RNFL defect to the center of the fovea (angle I) and the sum of the angular width of the defects (angle II) were determined. The patterns of localized RNFL defects were then compared with respect to differences in angles I and II.ResultsAngle I was significantly smaller in the high myopia group than in the low to moderate myopia group (p = 0.028) and the emmetropia group (p = 0.044), while angle II was significantly larger in the high myopia group compared with the low to moderate myopia group and the emmetropia group (p < 0.001, p = 0.007).ConclusionsAmong subjects with NTG, localized RNFL defects are wider and closer to the fovea in eyes with high myopia than those with low to moderate myopia or emmetropia.

Update on the Prevalence, Etiology, Diagnosis, and Monitoring of Normal-Tension Glaucoma

“…In a comparison between NTG eyes with low-teen and high-teen baseline IOP, localized RNFL defects were closer to the center of the macula in those with low-teen baseline IOP, whereas no significant difference was found in the width of the defects. 87 Kim et al 88 reported that localized RNFL defects were wider and closer to the fovea in NTG eyes with high myopia than in those with low to moderate myopia or emmetropia.…”

Lamina Cribrosa Configuration in Tilted Optic Discs With Different Tilt Axes: A New Hypothesis Regarding Optic Disc Tilt and Torsion

“…12,13 This 34 process may stretch the optic nerve fibers in the temporal direction, leading to 35 damage of axons. [13][14][15][16][17][18] The risk of OAG is reportedly greater in eyes with a vertically 36 tilted optic disc, and that the degree of tilt is positively associated with the severity of 37 visual-field damage. 5, 9, 11, 12, 15 38 In certain cases, the elliptical optic discs are oblique or even horizontally oval.…”

“…9,11,12,15,41 On the other hand, it is generally believed that optic disc would not be restricted to axons at the inferior or superior poles, but rather it would 343 also affect the temporal fibers; however, loss of the papillomacular bundle is not 344 observed in all myopic tilted discs. 16,17 Similarly, if the entire optic disc was rotated in 345 the process of torsion, it would twist all of the axons around the optic disc; however, 346 the actual pattern of glaucomatous axonal damage does not support this 347 hypothesis. 5,8 In the present study, we postulated that optic disc torsion is another 348 form of optic disc tilt that is centered on the oblique axis rather than being the result 349 of optic disc rotation, and explored the mechanism underlying optic disc tilt or torsion inferotemporal RNFL, while inferiorly tilted optic discs exhibited RNFL thinning most 372 prominently in the inferior sectors, which concurs with the findings from previous 373 studies.…”

Relationship Between Location of Retinal Nerve Fiber Layer Defect and Curvature of Retinal Artery Trajectory in Eyes With Normal Tension Glaucoma

“…We defined the angle between the reference line and a line from the optic disc center to the point of the disc margin nearest the border of the superior NFLD as the supra-NFLD angle 1. 15,16 For the supra-NFLD angle 2, we drew a circle with a radius of onehalf the distance between the disc center and the fovea, and determined the points where the circle intersected the nearest border of the superior NFLD. Then a line was drawn between the intersecting point and the disc center.…”

“…Eyes with diffuse RNFL atrophy detected in the red-free photographs, which could not be defined as a localized defect, were also excluded. 15 From 232 NTG patients, 88 eyes of 88 patients met the entry criteria. Fifty-six eyes had supratemporal NFLDs and 69 eyes had infratemporal NFLDs; and 37 eyes had both supra-and infratemporal NFLDs.…”