Photographic assessment of changes in torsional strabismus

The horizontal and vertical components of strabismus are measured routinely and relatively easily in the clinical setting using prism-and-cover and/or corneal light reflex tests. The third dimension of ocular alignment, ocular torsion, is more difficult to assess. Objective torsional deviation (cyclotropia) is evaluated qualitatively with fundus examination. For quantitative assessment, however, fundus photography is needed, which may not always be available during a strabismus examination and typically requires pupil dilation. We present a simple, inexpensive photographic technique to assess changes in iris torsion and evaluate its accuracy by comparison with fundus photography. Using a consumer-grade digital camera, basic photographic editing software, and a data worksheet, this technique assesses changes in objective torsion with accuracy and retest variability of both approximately 1 degrees.