The subjective controllability of exotropia and its effect on surgical outcomes in patients with intermittent exotropia

Background/aims We evaluate the clinical characteristics of intermittent exotropia with controllability and compare surgical outcomes between patients with and without controllability. Methods We reviewed the medical records of patients aged 6-18 years with intermittent exotropia who underwent surgery between September 2015 and September 2021. Controllability was defined as the patient's subjective awareness of exotropia or diplopia associated with the presence of exotropia and ability to instinctively correct the ocular exodeviation. Surgical outcomes were compared between patients with and without controllability, with a favorable surgical outcome defined as an ocular deviation between <= 10 PD of exotropia and <= 4 PD of esotropia at distance and near. Results Among 521 patients, 130 (25%, 130/521) had controllability. The mean age of onset (7.7 years) and surgery (9.9 years) were higher in patients with controllability than in those without controllability (p < 0.001). The mean control scores of patients with controllability (distance: 1.9, near: 1.5) were lower compared with patients without controllability (distance: 3.0, near: 2.2), reflecting a better level of control. Patients with controllability had a better surgical outcome than those without controllability, as analyzed by log-rank test (p < 0.001). Larger preoperative ocular exodeviation at distance (hazard ratio [HR] = 1.083, confidence interval [CI] = 1.018-1.151, p = 0.012) and near (HR = 1.102, CI = 1.037-1.172, p = 0.002) were significantly related to recurrence in patients with controllability. Conclusions Patients with controllability showed better surgical outcomes, later exotropia onset, and better level of control than patients without controllability. Preoperative ocular exodeviation was a significant factor influencing favorable outcomes in patients with controllable exotropia.