Strabismus, Strabismus Surgery, and Reoperation Rate in the United States: Analysis from the IRIS Registry

Purpose: To describe the rates of strabismus, strabismus surgery, and strabismus surgery reoperations among all age groups in the United States. Design: Retrospective analysis of electronic health record data. Participants: Patients from the IRIS (Intelligent Research in Sight) Registry. Methods: Description of the types and rates of strabismus and strabismus surgery from 2013 to 2016 with subgroups by age, sex, race/ethnicity, and region of the United States. Main Outcome Measure: The 1-year reoperation rate for strabismus surgery performed during 2013–2015 for all age groups. Results: A total of 30 827 185 unique patients were identified; 846 477 (2.75%) had a diagnosis of strabismus: 3.02% of male patients and 2.55% of female patients (difference = 0.47%, 95% confidence interval [CI], 0.46–0.48, P < 0.0001). Strabismus surgery was performed in 40 780 (0.13%) unique patients during the 4 years. The rate of surgery ranged from 1.99% for children birth to 5 years of age to 0.05% for adults 40 years of age and older. Horizontal surgical codes were reported 38 813 times, vertical surgery codes were reported 9304 times, and superior oblique codes were reported 711 times. Adjustable sutures were used for 3027 patients (7.42%). Cases with a code for repeat eye muscle surgery or restrictive myopathy were reported for 6098 patients (14.9%). Esotropia accounted for 30.06% and exotropia in 21.77% of diagnoses reported for surgery. The rate of undergoing a reoperation within 1 year of a strabismus surgery was 6.72%, lowest for the group 6 to 9 years of age (3.95%) and increasing with age (P < 0.001) to 11.5% for patients 65 years of age and older. Conclusions: Strabismus is an uncommonly reported diagnosis in ophthalmologic practice. Overall, approximately 1 in 750 patients in the IRIS Registry received strabismus surgery (1 in 20 with a strabismus diagnosis) during a 4-year period. Reoperations during the first year after surgery were performed for 1 in 15 patients, increasing with age at surgery. “Big” data from clinical data registries represent real-world care that can be used to develop benchmarks for clinical outcomes and to identify areas for practice improvement and training program design.