Multisectorial changes in the ciliary muscle during accommodation measured with high-resolution optical coherence tomography

Abstract

To measure changes in the anterior ciliary muscle during accommodation at the nasal, superior, temporal, and inferior sectors by means of an anterior chamber optical coherence tomographer, and correlate them with vergence changes. Methods: Twenty-four subjects with healthy, phakic eyes, whose mean age was 27.1 ± 8.9 years, underwent measurement with an anterior chamber optical coherence tomographer. The anterior ciliary muscle was measured at the nasal, temporal, superior, and inferior sectors for 0,-1,-2, and-3 D of vergence. A linear model was used to assess the correlation of each eye parameter with the accommodative demand. Results: The anterior ciliary muscle area significantly increased with accommodation for each sector, with a maximum increase of about 30% for the nasal-temporal sectors and about 25% for the inferior-temporal sectors. The linear model showed a tendency toward a positive relationship between change in the ciliary muscle area of each sector and vergence. Conclusion: The anterior ciliary muscle area tends to increase with accommodation, although the increase has been shown to be symmetric between the pair sectors superior-nasal and inferior-temporal. These results may help to increase understanding of accommodation biometry and biomechanics.

Optic Coherence Tomography for Accommodation Control in Children with Hyperopic Anisometropia and Amblyopia

“…The first information about physiological functioning of the ciliary muscle in static conditions was obtained from the results of the postmortem histological examinations of the rhesus monkeys having the accommodative structure of the eyes similar to that of humans [3]. It has been previously reported on the differences in the morphology of the ciliary muscle of the young and adult eyes [4][5][6] although the effect of these differences on the muscle functioning has not been shown. Images of the lens and/or ciliary muscle in static accommodation conditions were acquired using magnetic resonance imaging (MRI), ultrasound, Scheimpflug camera, ultrasound biomicroscopy (UBM), and time-domain optical coherence tomography (OCT) at the wavelengths of about 1300 nm [5,6].…”

“…It has been previously reported on the differences in the morphology of the ciliary muscle of the young and adult eyes [4][5][6] although the effect of these differences on the muscle functioning has not been shown. Images of the lens and/or ciliary muscle in static accommodation conditions were acquired using magnetic resonance imaging (MRI), ultrasound, Scheimpflug camera, ultrasound biomicroscopy (UBM), and time-domain optical coherence tomography (OCT) at the wavelengths of about 1300 nm [5,6]. MRI produces distortion-free images, but a low velocity of image production limits its application for the study of dynamic accommodation.…”

Performance of the Deep Neural Network Ciloctunet, Integrated with Open-Source Software for Ciliary Muscle Segmentation in Anterior Segment OCT Images, Is on Par with Experienced Examiners

“…Only a few studies have used narrower reading steps [ 8 , 24 ] or determined continuous thickness profiles [ 10 ]. Alternatively, the cross-sectional area of the ciliary muscle was assessed [ 22 , 25 , 26 , 27 , 28 , 29 , 30 ]. To facilitate the comparison of the results of different studies, suggestions have been made to harmonize the analysis of the ciliary muscle [ 31 ].…”

Review of the application of the open-source software CilOCT for semi-automatic segmentation and analysis of the ciliary muscle in OCT images

“…To date, the shape changes of the ciliary muscle during accommodation were analyzed by measuring the ciliary muscle thickness (CMT) either in equidistant steps posterior to the scleral spur [3,5] or proportionally to the length of the muscle [9]. Alternatively, the change of the ciliary muscle's area during accommodation is measured [8,10,11]. Both approaches require the segmentation of the ciliary muscle, which is usually performed manually, either using built-in calipers of the OCT-system [7,8], custom-developed programs [9,[12][13][14], or image processing software [10,11].…”

“…Alternatively, the change of the ciliary muscle's area during accommodation is measured [8,10,11]. Both approaches require the segmentation of the ciliary muscle, which is usually performed manually, either using built-in calipers of the OCT-system [7,8], custom-developed programs [9,[12][13][14], or image processing software [10,11]. The diversity of tools and methods for the segmentation of the ciliary muscle as well as of the analyzed parameters results in difficulties in comparing outcomes of different studies.…”