Purpose: The term congenital exotropia (XT) is typically reserved for patients presenting in the first year with a large, constant angle, however, no published study provides a rationale for this restrictive definition. In this study, the present classification system for XT was evaluated and differences between infants with constant versus intermittent XT at presentation were characterized.
Methods: Medical records of all patients diagnosed with XT before 12 months of age between 1980 and 1994 were identified by computer search. Exclusion criteria included previous eye muscle surgery, resolution of the XT by 3 months of age, and concomitant systemic or ocular disease. Patients were separated into intermittent XT and constant XT groups. The clinical characteristics and outcomes of these two groups were compared.
Results: Of 2018 patients examined on our service during the first year of life for all causes, 23 (1.1 %) met the inclusion criteria. Follow-up data of more than 1 year was available for 13 patients, and of these, 46% had constant XT. The 2 groups had similar clinical features at presentation except for a larger initial angle in the constant XT group (P =.02). Average follow-up was 58 months (range: 13-158 months). Twelve patients (92%) required surgery. The reoperation rate was 27%, and 82% had final horizontal deviations of less than 10 PD. The incidence of A/V-patterns (38%), dissociated vertical deviation (46%), and binocularity (70%) was similar between groups.
Conclusion: Half of infantile XT patients may present with intermittent XT, with similar clinical outcomes regardless of presentation. Surgical intervention resulted in successful alignment in most cases. More than half the patients developed measurable stereopsis, but none achieved bifixation.