OCT measurements of eye muscles for Grave’s disease
Reviewed by Fiona Rowe

The purpose of this study was to use optical coherence tomography (OCT) to assess horizontal rectus muscle thickening in patients with active and inactive Grave’s ophthalmopathy (GO) compared to healthy controls. This was a cross section observation study of rights eyes of 55 controls, 45 with clinically inactive GO and 12 active GO. Eighty-seven percent were hyperthyroid and 13% euthyroid. OCT images were obtained with Spectralis and muscle tendon thickness was measured using the OCT caliper function. In a subgroup of 15 eyes with GO (10 inactive and five active) intra and inter observer reproducibility of the measures was assessed. There was no significant difference across groups for age or sex. The average disease duration was 57.3±56.2mm (inactive) and 14.6±11.6mm (active). In controls, measures were made at 8.5mm from the limbus in 93% and at 10.5mm in 78% for the lateral rectus. Measures were made at 7.2mm from the limbus in 95% and at 9.2mm in 86% for the medial rectus. For inactive eyes, measures for these respective distances were 87% and 73% for the lateral rectus and 98% and 87% for the medial rectus. For active eyes, measures were 75% and 42%. Differences for the active eyes were due to pain and chemosis limiting inward gaze. Intra and inter observer reproducibility by intraclass correlation was 0.92 and 0.894 for the lateral rectus, and 0.954 and 0.939 for the medial rectus. OCT measures showed thicker horizontal rectus tendons in patients with GO than controls and thicker measures for active than inactive eyes. The authors propose that OCT could be useful to establish severity of disease.

Optical coherence tomography thickness measurements of the extraocular rectus muscle tendons in Grave’s ophthalmopathy.
De Pablo Gomez de Liano L, Fernandez Vigo JI, Ventura Abren N, et al.
JOURNAL OF PEDIATRIC OPHTHALMOLOGY AND STRABISMUS
2018;55:356-62.