A new device to assess static ocular torsion

Abstract

In clinical settings, static ocular torsion is assessed by taking a fundus photograph and measuring the angle between a horizontal line and the line connecting the fovea to the head of the optic nerve (centro-cecal axis rotation; CCAR). We developed and tested a system specifically aimed at CCAR measurements, based on low-cost commercial hardware, and that implements an adaptive research algorithm that selects and presents bright dots on a monitor to outline the borders of the blind spot, locate its center, and measure CCAR. We examined 10 healthy subjects who underwent four CCAR measurements to evaluate the reliability of the system and compared our results with those of fundus photographic examination. Our data showed an excyclophoria, with mean ocular torsion of 6.4° in the right and 6.7° in the left eye. These values are in keeping with those in the literature. Moreover, the values of the intraclass correlation coefficients suggest excellent reliability of the technique.

Objective cyclodeviation measurement in normal subjects by means of Cyclocheck® application

“…4,5 A variety of subjective and objective techniques have been proposed to evaluate cyclodeviation. 3,6–11 Subjective methods suffer from limitations related to sensory and psychological adaptations; therefore, they are usually not suitable for children and patients without binocularity. 12 Standard technique for objective cyclotorsion evaluation involves determination of the anatomic alignment of the globe around the antero-posterior axis based on measurement of the disk-foveal angle (DFA).…”