Pseudostrabismus in the First Year of Life and the Subsequent Diagnosis of Strabismus.

Purpose: To report the population-based birth prevalence of pseudostrabismus in the first year of life and the subsequent diagnosis of strabismus.

Design: Retrospective population-based cohort study.

Methods: All residents of Olmsted County, Minnesota ≤1 year old diagnosed with pseudostrabismus from January 1, 2005 through December 31, 2014, were identified using a medical record linkage system that captures virtually all medical care provided in a single Midwestern United States county population. The birth prevalence of pseudostrabismus and the subsequent diagnosis of strabismus were assessed.

Results: A total of 184 infants were diagnosed with pseudostrabismus during the 10-year study period, which yielded a birth prevalence of 1 in 113 children in the first year of life. There were 165 (89.7%) infants initially diagnosed by a non-ophthalmology care provider (NOCP) and confirmed by an ophthalmologist, 13 (7.1%) patients were diagnosed by an ophthalmologist alone, and 6 (3.3%) patients were diagnosed by a NOCP alone. Eighty-eight (49.4%) infants had at least 1 follow-up visit with an ophthalmologist, and the median follow-up time from pseudostrabismus diagnosis to the last health care visit that included an eye examination was 7.7 years (interquartile range: 5.8 years). Nine (4.9%) of the 184 infants were subsequently diagnosed with strabismus at a mean age of 4.5 years (range: 1.3 to 8.7 years) (7 with esotropia and 2 with exotropia).

Conclusion: Pseudostrabismus is a relatively frequent diagnosis in the first year of life. The prevalence of strabismus among infants with pseudostrabismus in this cohort was lower than those in previous reports and similar to strabismus rates reported in the same population.