Identification and biometry of horizontal extraocular muscle tendons using optical coherence tomography

Abstract

It is possible to visualize and measure HRMTs using AS-OCT. Measurements of the HRM, as well as the surrounding external ocular tissues, can be achieved.

Agreement Between Three Optical Coherence Tomography Devices to Assess the Insertion Distance and Thickness of Horizontal Rectus Muscles

“…OCT has a potential use in the diagnosis and monitoring of the therapeutic response in extraocular muscle diseases. 9,10 This study found that SS-OCT and SD-OCT are reliable and reproducible techniques for measuring the limbus insertion distance and the thickness of the horizontal rectus muscles, with good agreement between the different devices.…”

“…Park et al 16 also reported excellent reproducibility in measuring the horizontal extraocular muscle insertion distance with TD-OCT (ICC ≥ 0.96). Salcedo-Villanueva et al 9 reported excellent intra-observer reproducibility (ICC = 0.981) and inter-observer agreement (ICC = 0.834) when measuring the muscle thickness. In the current study, the reproducibility values and the percentage of identification were slightly higher with the SS-OCT device than with the SD-OCT devices.…”

“…Park et al 16 measured the lateral rectus muscle insertion to be within a range of 5.7 ± 0.6 to 6.4 ± 0.8 mm and the medial rectus muscle insertion from 5.1 ± 1.2 to 5.5 ± 1.4 mm with TD-OCT, but they concluded that the measurements were not significantly different with different eye positions. Salcedo-Villanueva et al 9 found a thickness of 136 µm (range: 95.5 to 217 µm) for the medial rectus muscle and 182 µm (range: 94.5 to 294.5 µm) for the lateral rectus muscle at the junction of the tendon using RTVue OCT (Optovue, Fremont, CA). These values are slightly lower than those observed in our study (medial rectus muscle mean from 163.9 to 170.7 µm depending on the device, range: 90 to 290; lateral rectus muscle mean from 199 to 203.3 µm, range: 101 to 350), possibly because we performed the measurements at a posterior site.…”

“…The second parameter studied was muscle thickness, which was measured with OCT by Salcedo-Villanueva et al 9 Later, Häner et al 10 compared the muscle thickness in patients with Graves orbitopathy to that of a healthy group.…”

Anterior Segment Optical Coherence Tomography of the Horizontal and Vertical Extraocular Muscles With Measurement of the Insertion to Limbus Distance

“…20 Salcedo-Villanueva et al imaged the horizontal extraocular muscles and measured the lengths of tendons and thickness of the muscles, conjunctival epithelium, sclera, and Tenon's capsule. 21 These studies did not measure the superior and inferior rectus muscle insertions and the measurements of the insertions were taken from an arbitrary calculated limbus, from either the anterior chamber angle or scleral spur. The study by Ngo et al is the only one to date that has imaged the extraocular rectus muscles with AS-OCT in a pediatric population, re-operated muscles, and imaged the vertical rectus muscles.…”