Abstract
Abstract: :
Purpose: To assess a possible correlation between ciliary body thickness and refractive error. Methods: Ninety patients without history of intraocular surgery were enrolled in the study. A–scan was performed to measure the axial length and ultrasound biomicroscopy (UBM) to measure the thickness of the ciliary body and of the wall of the eye (conjunctiva, sclera and ciliary body) at the scleral spur and at 2 and 3 mm posterior to it. UBM was performed by one of the observers (CO) at the temporal meridian of the eye. The two observers (CT and CO) independently obtained the UBM measurements and they were both masked to the data. Results: Mean patient age was 55.0 ± 15.1years. Mean spherical equivalent was – 1.41 ± 4.85 diopters. Interobserver reproducibility was good with CV of 1.1%, 3.3%, and 3.1 % for eye wall thickness at the scleral spur, 2 and 3 mm, respectively. And for ciliary body thickness at 2 and 3 mm posterior to the scleral spur CV was 8.0 and 11.4%, respectively. Refractive error correlated negatively with eye wall thickness at 2 and 3 mm posterior to the scleral spur (r = –0.57, P< 0.0001 and r = –0.38, P = 0.0002 for CT; r = –0.56 and r = –0.40, P< 0.0001 for CO), but not at this landmark (P> 0.05). There was a negative correlation between refractive error and ciliary body thickness at 2 and 3 mm (r = –0.63 and r = –0.46, P< 0.0001 for CT; r = –0.59 and r = –0.49, P< 0.0001 for CO). Axial length correlated positively with eye wall thickness at 2 and 3 mm (r = 0.64 and r = 0.41, P< 0.0001 for CT; r = 0.61, P< 0.0001 and r = 0.39, P = 0.0001 for CO). Axial length also correlated with ciliary body thickness at 2 and 3 mm posterior to the scleral spur (r = 0.69 and r = 0.49, P< 0.0001 for CT; r = 0.63 and r = 0.48, P< 0.0001 for CO). Conclusion: Ciliary body thickness at 2 and 3 mm posterior to the scleral spur and eye wall thickness at the same sites correlate negatively with refractive error and positively with axial length.
Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • ciliary body • refractive error development