Asymmetry of Optic Nerve Head Parameters Measured by Confocal Scanning Laser Ophthalmoscopy in Myopic Anisometropic Eyes

Abstract

Background: This study aimed to evaluate the asymmetry of optic nerve head parameters measured by confocal scanning laser ophthalmoscopy (CSLO) in myopic anisometropic eyes. Methods: A total of 36 eyes of 18 healthy myopic anisometropic subjects, defined as cases in which the difference in spherical equivalent (SE) between both eyes is ≥1.5D, were recruited. The optic nerve heads were measured using the Heidelberg retina tomograph II (Heidelberg Engineering, GmBH, Heidelberg, Germany). Differences in optic nerve head parameters between more myopic eyes and fellow eyes were evaluated using the paired-sample t-test. Pearson correlation and multiple linear regression analysis were used to evaluate factors associated with cup/disc ratio (CDR). Results: The cup/disc area ratio (mean difference 0.07 ± 0.11, P = 0.027), horizontal (mean difference 0.10 ± 0.17, P = 0.033), and vertical CDR (mean difference 0.13 ± 0.18, P = 0.008) were significantly smaller in more myopic eye. Larger disc area was independently and significantly associated with larger cup/disc area ratio (β = 0.561, P = 0.001) and vertical CDR (β = 0.499, P = 0.03). Conclusion: The CDR, horizontal, and vertical CDR were significantly smaller in the more myopic eyes in myopic anisometropic subjects. Further studies with larger samples are needed to confirm the asymmetry of the optic nerve head in myopic anisometropic eyes.