A Novel Method for Evaluation of Ocular Torsion Angle by Optical Coherence Tomography

Abstract

Purpose: The Glaucoma Module Premium Edition (GMPE) software for the SPECTRALIS optical coherence tomography (OCT) is able to automatically track the anatomic centers of both the fovea and the optic disc. We investigated the efficacy of the OCT in measuring the ocular torsion angle before and after strabismus surgery.

Methods: Between June 2017 and December 2018, 40 patients with cyclodeviation who had undergone strabismus surgery at Hyogo College of Medicine were enrolled. Ocular torsion angle measurements, including OCT and nonmydriatic fundus camera for objective measurements and synoptophore for subjective measurements, were performed before surgery and 1 day after surgery.

Results: The ocular torsion angles were measured as follows: synoptophore preoperative (-8.8° ± 4.1°) and postoperative (-3.1° ± 2.8°), fundus photography preoperative (-27.2° ± 6.4°) and postoperative (-18.6° ± 5.9°), and OCT preoperative (-25.9° ± 6.8°) and postoperative (-18.2° ± 5.8°). In all cases, symptoms related to cyclodeviation resolved postoperatively. All measurements were positively correlated before surgery. Postoperatively, changes in all measurements were also correlated. However, all synoptophore-related data were underestimated when compared with OCT and fundus photography.

Conclusions: For measuring the ocular torsion angle, the OCT-based technology GMPE appears to provide information regarding anatomic fundus torsion that is similar to that obtained using fundus photography.

Translational relevance: This new objective measurement for the ocular torsion angle is helpful for treating cyclotropia.

Keywords: Bland–Altman plots; cyclodeviation; cyclotropia; ocular torsion angle; optical coherence tomography.

Figure 1.

(a) OCT scans the retina, and GMPE automatically detects the centers of the optic disc and fovea, and then the software calculates the ocular torsion angle. (b) Magnification of the ocular torsion angle. The picture shows an ocular torsion angle of –16.5°.

Figure 2.

Preoperative correlation of ocular torsion angle (a). OCT is moderately correlated with synoptophore. (b) OCT is strongly correlated with fundus photography.

Figure 3.

Bland–Altman plots. (a) Comparisons between OCT and the synoptophore did not show good agreement. (b) Comparisons between OCT and the fundus camera showed good agreement.