Infrared photographs with a selective wavelength filter to diagnose small-angle esotropia in young children.

Abstract

To validate the effectiveness of the selective wavelength filter analysis with infrared photographs for diagnosing small-angle esotropia in children under age 4. This is a retrospective, observational, case-control study. A total of 83 esotropes with an esodeviation of ≤ 16 prism diopters (PD) and 75 orthotropic controls under 4years of age were included. Full-face infrared photographs were taken with a selective wavelength filter in front of either eye. The angles of esodeviation on photographs were measured with the three-dimensional Strabismus Photo Analyzer. The alternateprism and cover test or the Krimsky test were repeatedly performed to measure ocular alignment. The testability of infrared photographs using selective wavelength filters in children under 4years of age was 85.6%. The mean angle of esodeviation was 11.3 ± 4.0PD by manual measurements and 11.5 ± 4.4PD by the infrared photograph analysis. Manual measurements and the infrared photograph analysis showed a strong positive correlation (R = 0.815, P < 0.001). The sensitivity and specificity of the infrared photograph analysis for detecting small-angle esotropia were 95.2% and 77.9%, respectively, with a cutoff value of 4.0PD. The automated infrared photograph analysis was simple and effective for diagnosing small-angle esotropia in young children.