Purpose: This study was conducted to evaluate the correlation between ciliary muscle thickness and myopia in Saudi females using anterior segment optical coherence tomography (AS-OCT).
Subjects and Methods: This study was a prospective, non-randomized, crosssectional, observational, and quantitative study. The study included 65 eyes (33 myopic eyes and 32 non-myopic eyes). All subjects underwent a complete ophthalmic examination, measurement of the refractive error, central corneal curvature (CCC), axial length (AL) and anterior chamber depth (ACD). Ciliary muscle thickness (CMT) at 1 mm, 2mm and 3mm (from the scleral spur) was measured using AS-OCT (Visante; Carl Zeiss).
Results: Concerning comparison between myopic and non-myopic eyes, there was a statistically significant difference in temporal CMT (TCMT2, TCMT3) (P<0.05). Alternatively, there was no statistically significant difference in TCMT1 (P=0.54). On the other hand, there was a statistically significant difference in nasal CMT (NCMT3) (P=0.001). Though, there was no statistically significant difference in NCMT1, NCMT2 (P>0.05). The myopic eyes showed a statistically insignificant positive correlation between AL and all measures of CMT except for CMT1. In addition, there was a statistically insignificant positive correlation between mean spherical error (MSE) and most measures of CMT. Furthermore, there was a statistically insignificant negative correlation between CCC and CMT. Additionally, there was a statistically insignificant positive correlation between ACD and all measures of CMT.
Conclusion: This study documented increased CMT in myopic eyes. Future studies are recommended to evaluate structural characteristics of the ciliary muscle in the context of 3-D morphological features of the globe that are better indicators of architectural changes that occur in myopia.
Keywords: Ciliary muscle thickness, Myopia, Axial length, Mean spherical error, Anterior segment optical coherence tomography