Strabismus outcomes after surgery: the nationwide SOS France study

To describe the types of strabismus operated on, the surgical procedures performed, and the 2-year reoperation rate in France.

Entire population 5-year cross-sectional analysis of a national medico-administrative database in France between January 2013 and December 2017 included all patients who underwent a first strabismus surgery, with a 2-year follow-up. Patient identification was based on the diagnostic codes of the 10th International Classification of Diseases and surgical procedures on the codes of the Common Classification of Medical Acts. A subgroup analysis comparing non-paralytic and paralytic strabismus was performed.

Among the 56,654 patients included (women: 50.8%), 26,892 (47.5%) patients were under 10 years old. Overall, 52,711 (93%) were diagnosed with non-paralytic strabismus and 3,943 (7%) with paralytic strabismus. Among the non-paralytics, the most frequent diagnosis was esotropia (21,282, 37.6%), followed by exotropia (14,392, 25.4%) and vertical strabismus (2,017, 3.6%). Among the paralytics, fourth cranial nerve palsy (1,499, 2.6%) was more frequent than sixth cranial nerve palsy (691, 1.2%) and third cranial nerve palsy (431, 0.8%). The 2-year reoperation rate was 7.7% (4,362 patients), the lowest for non-paralytic (7.4%) and the highest for paralytic (11.4%).

This first French population-based study about strabismus will contribute to the evaluation of practices at a national level and permit comparisons between countries. Although the 2-year reoperation rate was found to be 1 out of 13 patients, it should be interpreted with caution. Long-term follow-up is still warranted due to considerable variability of the type and severity of strabismus as well as surgical practices.