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

Purpose: To evaluate the range of cyclodeviation in normal individuals by means of Cyclocheck ^® application recently designed by the authors and freely available at www.cyclocheck.com.
Methods: Healthy subjects with normal muscle balance, best-corrected visual acuity of ⩾0.8, and stereopsis on Randot charts of ⩽100 s of arc were included in the study. Two separate digital fundus photographs were taken of each eye of every patient. The disk-foveal angle was calculated using the Cyclocheck ^® application. The average result of the disk-foveal angle measurements were considered for data analysis.
Results: A total of 131 patients met inclusion criteria for the study population. The mean value of the disk-foveal angle in the whole study group (both right and left eye) was 6.39° ± 2.72° with 5.26° ± 2.56° (range from -0.4° to 12.55°) in the right eye and 7.52° ± 2.39° (range from 1.25° to 12.76°) in the left eye. The mean value of the disk-foveal angle of the left eye was greater by 2.26° than that of the right eye.
Conclusion: Cyclocheck ^® software allows easy assessment of cyclodeviation. Normal individuals present with a positive value of the disk-foveal angle with a certain spread of the results. The analysis of obtained measurements revealed a significant asymmetry between both eyes with the left eye being more excyclodeviated in an otherwise orthotropic population, which remains a subject for further investigations.