Purpose: To report the rate of ocular torsion in children with horizontal strabismus or orthophoria.
Methods: A retrospective study design was used. Nineteen children were included in the study, including seven girls, aged 4-16 years. All patients were examined for strabismus and 12 were scheduled for surgical intervention. All participants had digital fundus photos (DRSplus, Padova, Italy) of both eyes at presentation, and 5 of 12 also had fundus photos following the strabismus operation. Patient files were reviewed for age, demographic data, type of strabismus, clinical symptoms and signs, orthoptic exams, subjective and objective reports of torsion, inferior oblique overaction, and V pattern. Fundus photos were analyzed for torsion by ImageJ software [ImageJ 1.54f, National Institute of Health, USA]. The disc-foveal angle was calculated for ocular torsion. Disc-foveal angle was defined as the angle formed between a line passing through the center of the optic disc to the fovea and another horizontal line passing through the center of the optic disc, using fundus photographs.
Results: Of the 19 children, 18 had horizontal strabismus: 9 with exotropia and 9 with esotropia. One child was orthophoric with torsional strabismus. Inferior oblique overaction was detected in all but 3 children, while V pattern was documented in 10. Visual acuity was reduced (under 6/12) in four eyes of four children. None were symptomatic for ocular torsion. Although extorsion was documented clinically in 3 of 19 children, it was measurable on fundus photos in all patients before surgery with a mean of 8.7 ± 8.5 degrees and 8.5 ± 9.7 degrees in the right and left eyes, respectively. The mean extorsion in both eyes was 19.7 ± 10.1 degrees and improved to a mean of 15.3 ± 7.9 degrees in the children who were operated on and had documented postoperative fundus photographs.
Conclusions: Extorsion was detected on fundus photos at a significantly higher rate than in clinical examination. Notably, inferior oblique overaction was mainly associated with torsion. This study demonstrated that torsion is underdiagnosed in clinical examinations, as the children are often asymptomatic, but fundus photos which are easily obtained can improve its detection.
Keywords: fundus photos; strabismus; strabismus surgery; torsion.