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

Abstract

Purpose: To determine the effectiveness of part-time patching for treating intermittent exotropia (IXT) in young children.

Design: Multicenter, randomized clinical trial.

Participants: Two hundred one children 12 to 35 months of age with untreated IXT meeting the following criteria: (1) IXT at distance OR constant exotropia at distance and either IXT or exophoria at near, and (2) 15-prism diopter (Δ) or more exodeviation at distance or near by prism and alternate cover test (PACT) but at least 10 Δ exodeviation at distance by PACT.

Methods: Participants were assigned randomly to either observation (no treatment for 6 months) or patching prescribed for 3 hours daily for 5 months, followed by 1 month of no patching.

Main outcome measures: The primary outcome was deterioration, defined as constant exotropia measuring at least 10 Δ at distance and near or receipt of nonprotocol treatment for IXT.

Results: Of the 177 participants (88%) completing the 6-month primary outcome examination, deterioration occurred in 4.6% (4 of 87) of the participants in the observation group and in 2.2% (2 of 90) of the participants in the patching group (difference, 2.4%; P = 0.27; 95% confidence interval, -3.8% to +9.4%). Motor deterioration occurred in 2.3% (2 of 87) of the observation group and in 2.2% (2 of 90) of the patching group (difference, 0.08%; P = 0.55; 95% confidence interval, -5.8% to +6.1%). For the observation and patching groups, respectively, 6-month mean PACT measurements were 27.9 Δ versus 24.9 Δ at distance (P = 0.02) and 19.3 Δ versus 17.0 Δ at near (P = 0.10); 6-month mean exotropia control scores were 2.8 versus 2.3 points at distance (P = 0.02) and 1.4 versus 1.1 points at near (P = 0.26).

Conclusions: Among children 12 to 35 months of age with previously untreated IXT, deterioration over 6 months was uncommon, with or without patching treatment. There was insufficient evidence to recommend part-time patching for the treatment of IXT in children in this age group.

Figure 1. Flow of Participants through Study

^aDue to poor cooperation, masked alignment testing could not be completed for 5 participants at the 3-month visit (3 in observation and 2 in patching) and 2 participants at the 6-month visit (1 in each group). ^bThe observation group includes 1 participant who was lost to follow-up and 2 participants who are continuing in the longer-term study follow-up but did not complete the 6-month visit and therefore are excluded from the analysis. The patching group includes 4 participants who were lost to follow-up and 3 participants who are continuing in the longer-term study follow-up but did not complete the 6-month visit and therefore are excluded from the analysis. ^cIn the observation group, 2 participants were withdrawn from the study for outcome-related reasons. One child's mother and the pediatrician felt the IXT had resolved. The other child's parents felt their child's eyes were getting worse and wanted surgery. ^dIn the patching group, parents withdrew 1 child because they were transferring care to another ophthalmologist.