Assessment of objective ocular cyclodeviation under monocular condition and binocular condition using fundus photography

Development and Preliminary Validation of a Virtual Reality Approach for Measurement of Torsional Strabismus

BACKGROUND

Double Maddox rod (DMR), the gold-standard method for in-office measurement of cyclodeviation, requires an examiner and specialized equipment. The objective of this study was to develop a virtual reality (VR) technique for measurement of cyclodeviation and validate this against the DMR.

METHODS

A VR-DMR was implemented using a smartphone and commercially available VR viewer. The app displayed a line to each eye and accepted touch inputs from the user to rotate the lines into perceived alignment. VR-DMR cyclodeviation measurements were compared with traditional DMR (T-DMR) cyclodeviation measurements in adults with and without strabismus and children without strabismus.

RESULTS

Thirty-one subjects were studied (age 5-88 years, 20 with strabismus). VR-DMR had similar test-retest reliability as T-DMR. VR-DMR was highly correlated with T-DMR (r2 = 0.94, linear regression slope 1.12) with a slight positive bias (linear regression y intercept 1°). VR-DMR was preferred by 54% of subjects with 29% having no preference.

CONCLUSIONS

A VR method of ocular cyclodeviation measurement using sensory techniques was implemented using commercially available hardware. VR measurements compared favorably with gold-standard DMR measurements, and user feedback was positive. The VR methodology has application for in office and home use by nonexperts for purposes of strabismus monitoring.