Changes in angle of optic nerve and angle of ocular orbit with increasing age in Japanese children

Abstract

PurposeTo study changes in the opening angle of the optic nerve and the angle of the ocular orbit with increasing age in normal Japanese children.MethodsWe studied 147 normal children (aged 6 months to 18 years) who had undergone CT as a diagnostic procedure. Measurements were performed on axial CT images that included the entire optic nerve of both eyes. The opening angle of the optic nerve was defined as the angle formed by the intersection of a line running through the left optic nerve and a vertical line passing through the centre of the nose. The opening angle of the orbit was defined as the angle formed by the intersection of a line running tangentially along the deep lateral wall of the left orbit and a vertical line passing through the centre of the nose. The relationship between age and these opening angles was analysed by regression analysis.ResultsThe correlation between age and opening angle of the optic nerve was not significant. In contrast, the opening angle of the orbit decreased relatively rapidly until about 2–3 years of age, and then it stabilised. The decrease in the opening angle of the orbit with increasing age was significant (p<0.001). The relationship between these two parameters was best fitted by a logarithmic regression curve.ConclusionsBecause the opening angle of the orbit decreased significantly with increasing age, this factor must be considered when diagnosing and treating strabismus in children.

What is the Main Potential Factor Influencing Ocular Protrusion?

“…CT imaging has been widely used for many years to observe inner structure from various angles, accurately measure orbital parameter values, and evaluate facial asymmetry [30]. Previous studies [2,31,32] have evaluated different methods of ocular protrusion measurement in a two-dimensional plane. However, typically, the apex of the cornea is not in the same CT imaging plane as the most posterior part of the lateral margin of the orbit, leading to some uncertainties or errors during measurements.…”

Ophthalmoscopic-Perspectively Distorted Optic Disc Diameters and Real Disc Diameters

“…Previous studies have shown the change in the orientation of the optic nerve head with increasing age in myopic children. 23 Future studies may specifically address the change in the rotation of the optic nerve head in children in dependence on the refractive error.…”

Developmental change of the biorbital angle in normal Japanese infants

“…It has been reported that the angle of the orbit measured between the medial and lateral orbital wall decreased until the age of 1 year, with little change noted thereafter. 11 – 13 The biorbital angle used in our study was approximately equal to the total amount of the right and left angles measured by Escaravage and Dutton. 12 Furthermore, our results showed that the biorbital angle became narrower at the age of 1 year and then remained unchanged, which matches with the previous results of Escaravage and Dutton.…”

“…Furthermore, this decrease in the opening angle of the orbit with increasing age was statistically significant. 13 These findings additionally suggest that the decrease in the opening angle of the orbit may contribute to the decrease in the exodeviation that is seen in 70%–80% of normal newborns. 14 Furthermore, this morphological change might provide important information on the management of strabismus in infants.…”

“… 2 – 7 Although previous studies have clearly shown that the angle of the orbit gradually changes from wider to narrower as the gestation progresses, 8 – 10 there have been few studies that examined the development of the opening angle of the orbit after birth. 11 – 13 Tsukitome et al reported changes in the opening angle of the optic nerve and the angle of the ocular orbit with increasing age in normal Japanese children. Although there was no change with age in the opening angle of the optic nerve, defined as the angle formed by the intersection of a line running through the left optic nerve and a vertical line passing through the center of the nose, they found a relatively rapid decrease in the opening angle of the orbit, defined as the angle formed by the intersection of a line running tangentially along the deep lateral wall of the left orbit and a vertical line passing through the center of the nose, within 2–3 years of age, after which the angle then stabilized.…”