Monofixational Intermittent Exotropia

Is intermittent exotropia a curable condition?

“…For conservatively managed patients, we found the rate of monofixation ranged from 13% (interim examination) to 21% (5-year follow-up), which is similar to the prevalence of monofixation in unselected children presenting with intermittent XT reported in previous studies. 16,17 Although we have previously reported the risk of misclassifying monofixation due to test-retest variability, 16 we would expect any misclassification to be similar between non-surgical and surgical groups. We found the rate of monofixation was significantly higher at the 5-year outcome for surgically managed patients than for conservatively managed patients, suggesting that either monofixation was induced by surgical intervention, or that patients who underwent surgery already had, or were at higher risk for developing monofixation.…”

“…Previous authors have suggested that evidence of monofixation postoperatively is attributable to monofixation being present preoperatively. 17,26 Nevertheless, it appears that monofixation can be induced through surgical intervention, as highlighted in the study by Pratt-Johnson et al 23 Although it has been proposed that a postoperative microtropia with monofixation is a good result that lends itself to longterm motor stability, 27 our data suggest few if any of these patients did in fact have good long-term alignment. The now uncertain potential 'benefit' of long-term stable monofixation with a microtropia should be weighed against the potential 'harm' of inducing subnormal stereoacuity in patients where it was previously normal.…”

“…Such a definition of sensory success did not preclude patients with monofixation being classified as sensory successes at their follow-up examination if they had monofixation on their presentation preoperative or interim examinations, which we felt was reasonable because a proportion of patients presenting with XT already have monofixation. 16,17 We compared the proportion of patients in the surgical and non-surgical cohorts classified as 'cure' at the 5-year follow-up examination, and also the proportion of patients with monofixation at presentation and at followup examination time points, using Fisher's exact tests. We also compared mean angle of deviation (by PACT) between groups using t-tests, and we compared median distance and near office control scores between groups using Wilcoxon tests.…”

Comparison of sensory outcomes in patients with monofixation versus bifoveal fusion after surgery for intermittent exotropia

“…Although we chose our definition of nil stereopsis on Titmus testing on the basis of our clinical experience, there are monocular clues in the lower testing ranges (circles 1-4) that may make results difficult to interpret. 26 In short, a child may measure up to 140 arcsec on the Titmus test by monocular clues and truly have nil stereopsis. Of the children in our study with substantial improvement, we find it unlikely that these children had nil stereopsis because of the fact that they improved postoperatively.…”

Dissociated vertical deviation in patients with intermittent exotropia

“…8,9 Intermittent exotropia can be divided into two groups, monofixational and bifixational intermittent exotropia, according to the degree of binocularity. 10,11 Although monofixational intermittent exotropia may show a poor level of stereoacuity, 11,12 the stereopsis of most patients with intermittent exotropia is usually excellent. 13,14 The mechanism by which DVD develops in patients with intermittent exotropia who, however, have relatively normal binocular function in the aligned state has not been determined.…”