The Natural History of Exophoria Progression Among Young Healthy Adults

To evaluate the natural history of near exophoria in a large cohort of healthy young adults.

Retrospective study.

Young adults evaluated at the Israeli Air Force Aeromedical Center (IAF AMC) between 2018 and 2023.

Participants with ≥6 prism diopters (PD) of exophoria at near during their initial assessment were categorized as having exophoria. Eligibility required at least two ophthalmologic evaluations with a minimum interval of one year between the first and last visits. Assessments included ocular alignment, refraction, stereoacuity, and visual acuity.

Change in exophoria over time and factors associated with its progression.

Among 23,092 examined subjects, 14,409 (62.4%) exhibited some degree of near exophoria, and 5326 (23%) met the threshold of ≥6 PD. Of these, 369 subjects (1.6%; mean age 27.4 ± 15.6 years; 93% male) met inclusion criteria. At baseline, mean near exophoria was 7.49 ± 2.06 PD (range 6-22 PD). At the final follow-up, the mean exophoria was 7.56 ± 3.08 PD (range 2-18 PD), representing a non-significant change (P = .680). Myopia was the only factor significantly associated with an increase in exophoria over time. Stereoacuity remained consistently high throughout the study period, regardless of exophoria magnitude.

In this large sample of healthy young adults, near exophoria remained stable over time, with no clinically significant progression observed. However, individuals with myopia demonstrated a greater likelihood of exophoria progression. Despite this, stereoacuity was preserved across all participants, including those with marked exophoria.