Purpose:
To assess the changes of the human ciliary muscle during accommodation in a non-contact procedure.
Methods:
15 eyes of 15 subjects with preserved accommodation of at least 5 D were examined in this study with 1310nm anterior segment optical coherence tomography (OCT). A radial image of the ciliary muscle was taken transsclerally to avoid the optical absorption by the irispigment. The area of the muscle cross section was calculated with ImageJ (U.S.NIH, Bethesda, 1997-2006). The ciliary muscle was examined during desaccommodation in cyloplegia and maximal accommodation stimulated by an accommodometer. Each measurement consisted in 5 standardized scans to assess the repeatability of the measurement.
Results:
A good image quality of the radial ciliary muscle was obtained transsclerally whereas the transiridial image did not picture the whole muscle. The polymorphic ciliary processes were not displayed by OCT due to the limited penetration of the OCT signal. Morphological changes of the muscle were observed during accommodation. The muscle cross section area during desaccommodation was 1.205 ± 0.23 mm². The mean area increased to 1.401 ± 0.24 mm² during accommodation.
Conclusions:
Changes of the radial ciliary muscle during accommodation can be displayed by transscleral anterior segment OCT.
Keywords: ciliary muscle • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • imaging/image analysis: non-clinical