Purpose 

To report factors associated with preoperative squinting, defined as transient eye closure in bright light, and photophobia and the factors affecting improvement of these symptoms postoperatively in intermittent exotropia.

Methods 

In this retrospective study, patients (N = 99) were divided into groups according to the presence (n = 54) or absence (n = 45) of preoperative squinting and the presence (n = 64) or absence (n = 35) of photophobia. Clinical characteristics, including overaction or underaction of the oblique muscle and fundus intorsion and extorsion, were compared between the two groups. The squinting and photophobia groups were further categorized into two subgroups each according to postoperative improvement. The extended list of characteristics, including the duration from onset to surgery, postoperative angle of deviation, and fusion, was compared between the two subgroups.

Results 

Preoperatively, 54 (54.5%) and 64 (64.6%) patients had squinting and photophobia, respectively. The coincidence of squinting and photophobia was marginally significant (p = 0.05). Postoperatively, squinting and photophobia disappeared in 64.8 and 59.4% of the patients, respectively. The photophobia group had a younger onset age of strabismus than the nonphotophobia group (39.3 vs. 56.4 months; p = 0.03). Good fusional status at the near range was more common in the nonsquinting group than in the squinting group (74.3 vs. 47.6%; p = 0.02). Superior oblique overaction was significantly more common in the squinting group than in the nonsquinting group (11.1 vs. 0%; p = 0.03). Early surgical correction and successful outcomes were associated with squinting improvement (p = 0.001 and p = 0.02, respectively).

Conclusions 

More than 50% of patients with intermittent exotropia had squinting or photophobia, and approximately 60% of symptomatic patients experienced improvement postoperatively. The onset of strabismus, near fusion, superior oblique overaction, and fundus intorsion were related to these symptoms. Early surgery and successful eye position realignment were beneficial for improving squinting postoperatively.