A Randomized Trial Comparing Part-Time Patching with Observation for Children 3 to 10 Years of Age with Intermittent Exotropia

Abstract

Objective To determine the effectiveness of prescribed part-time patching for treatment of intermittent exotropia in children Design Multicenter, randomized clinical trial Participants Three hundred fifty-eight children aged 3 to < 11 years old with previously untreated (except for refractive correction) intermittent exotropia (IXT) and near stereoacuity of 400 arcsec or better were enrolled. Intermittent exotropia met the following criteria: 1) constant or intermittent exotropia at distance and either intermittent exotropia or exophoria at near; 2) exodeviation (tropia or phoria) of at least 15 prism diopters (Δ) at distance or near by prism and alternate cover test (PACT); and 3) exodeviation of at least 10Δ at distance by PACT. Methods Participants were randomly assigned to either observation (no treatment for 6 months) or patching for 3 hours per day for 5 months, with a 1-month washout period of no patching before the 6-month primary outcome exam. Main Outcome Measure The primary outcome was deterioration at either the 3-month or the 6-month follow-up visit, defined as: 1) constant exotropia measuring at least 10Δ at distance and near by simultaneous prism and cover test, and/or 2) near stereoacuity decreased by at least 2 octaves from baseline, both assessed by a masked examiner and confirmed by a retest. Participants who were prescribed any non-randomized treatment without first meeting either deterioration criteria were also counted as having deteriorated. Results Of the 324 (91%) participants completing the 6-month primary outcome exam, deterioration occurred in 10 (6.1%) of the 165 participants in the observation group (3 of these 10 started treatment without meeting deterioration criteria) and in 1 (0.6%) of the 159 participants in the part-time patching group (difference = 5.4%, lower limit of one-sided exact 95% confidence interval = 2.0%; p value from one-sided hypothesis test = 0.004). Conclusion Deterioration of previously untreated childhood IXT over a 6-month period is uncommon with or without patching treatment. Although there is a slightly lower deterioration rate with patching, both management approaches are reasonable for treating 3 to 10 year olds with IXT.

Is intermittent exotropia a curable condition?

“…1 Nevertheless, there is no consensus regarding the optimum type of treatment and the optimum timing of treatment. [2][3][4] Current management options include watchful waiting, 5 part-time occlusion, 4,6-8 over-minus spectacles, [9][10][11][12] fusion exercises, 13 and strabismus surgery. [2][3][4] Much of the controversy is due to limited data on the natural history of intermittent XT and limited data on the long-term outcomes with each type of intervention.…”

A Randomized Trial Comparing Part-time Patching with Observation for Intermittent Exotropia in Children 12 to 35 Months of Age

“…1 Both age cohorts and treatment groups taken together show that children with previously untreated IXT rarely develop constant exotropia over 6 months, on the order of about 1%. 1 …”

“…We have reported findings in children 3 to 10 years of age with IXT as a parallel cohort in the same randomized trial. 1 Because those children were old enough to measure stereoacuity, deterioration was defined as either motor deterioration, loss of stereoacuity (≥2 octaves), or receipt of non-protocol treatment. 1 In the older cohort, motor and sensory deterioration occurred slightly less often in the patching group (0.6%; N = 1 of 159) than in the observation group (6.1%; N = 10 of 165) (P = 0.004); however, there were no cases of motor deterioration (0.0%; N= 0 of 159) in the patching group and only a single case in the observation group (0.6%; N = 1 of 165).…”

“…1 Because those children were old enough to measure stereoacuity, deterioration was defined as either motor deterioration, loss of stereoacuity (≥2 octaves), or receipt of non-protocol treatment. 1 In the older cohort, motor and sensory deterioration occurred slightly less often in the patching group (0.6%; N = 1 of 159) than in the observation group (6.1%; N = 10 of 165) (P = 0.004); however, there were no cases of motor deterioration (0.0%; N= 0 of 159) in the patching group and only a single case in the observation group (0.6%; N = 1 of 165). 1 Both age cohorts and treatment groups taken together show that children with previously untreated IXT rarely develop constant exotropia over 6 months, on the order of about 1%.…”

“…This report represents the first phase of an ongoing 3-year study that also includes children aged 3-<11 years old 1 and also aims to assess the long-term natural history of IXT in the observation group. Relevant portions of the protocol are summarized below.…”