The Relationship Between Ciliary Body Thickness and Age in School-Age Children

Abstract

Purpose:: The ciliary body is involved in a number of ocular functions. Little is known about the development of this structure in children due to the difficulty of visualizing and measuring it. The purpose of this study is to determine the feasibility of measuring parameters of the ciliary body with the Zeiss Visante^TM Anterior Segment OCT, and to determine if there is a relationship between the size of the ciliary body and age in school-age children.

Methods:: 24 children between the ages of eight and 15 were included in the analyses. Images of the nasal ciliary body of the right eye were taken with the Visante under cycloplegic conditions. Each subject fixated on a peripheral target so that images of the ciliary muscle were obtained through the nasal sclera. The images were obtained in high resolution corneal mode. Ciliary body thickness was defined as the distance between the intraocular bounds of the sclera and the ciliary pigmented epithelium. Measurements were taken at 2 mm (CB2) and 3 mm (CB3) behind the scleral spur. The relationship between both CB2 and CB3 and age were calculated with an ordinary least squares regression model.

Results:: The mean (±SD) age of all subjects was 10.85 ± 2.12 years (range 8 to 15 years). The mean (±SD) of CB2 across the sample was 0.422 ± 0.090 and the mean (±SD) of CB3 across the sample was 0.220 ± 0.060. CB2 was significantly associated with age (estimate = -0.027, R² = 0.398, p < 0.001), indicating that the thickness of the ciliary body decreases with increasing age. CB3 was not significantly associated with age in the current sample of 24 subjects (estimate = -0.01, R² = 0.138, p = 0.07).

Conclusions:: Similar to the crystalline lens, the ciliary body thins with increasing age, and presumably eye growth, in school-age children. These data demonstrate that measurements of the ciliary body, which has historically been difficult to visualize due to its location within the eye, are feasible with the Visante^TM Anterior Segment OCT. Further studies are required to evaluate how the ciliary body interacts with other ocular components during the ocular growth that occurs in school-age children.

Keywords: ciliary body • refractive error development • anatomy