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Susan A Cotter, Brian G Mohney, Danielle L Chandler, Jonathan M Holmes, David B Petersen, Raymond T Kraker, David K Wallace; Natural History of Childhood Intermittent Exotropia Over a 3-year Period. Invest. Ophthalmol. Vis. Sci. 2016;57(12):No Pagination Specified.
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© ARVO (1962-2015); The Authors (2016-present)
To determine the rate of deterioration of intermittent exotropia (IXT) in children without treatment over 3 years.
183 children 3 to 10 years of age with previously untreated IXT and near stereoacuity of 400 arc sec or better were randomly assigned to an observation group as part of a randomized trial. Observation was defined as no IXT treatment other than refractive correction for 3 years unless deterioration criteria were met at 3 months, 6 months, or 6 month intervals thereafter until 3 years post-randomization. Protocol-allowed exceptions for starting treatment were overwhelming social concern, debilitating diplopia, and/or failure to maintain stereoacuity age norms. The primary outcome was deterioration by 3 years, defined as meeting a motor criterion (constant XT of 10pd or greater at distance and near) or a near stereoacuity criterion (decrease of 2 octaves or more from best previous measure), assessed by a masked examiner. For analysis, participants were also counted as having deteriorated if they were prescribed any treatment other than refractive correction without first meeting motor or stereoacuity deterioration criteria. The cumulative probabilities of meeting deterioration criteria by 1, 2, and 3 years and 95% confidence intervals (CI) were calculated using Kaplan-Meier survival analysis.
Of the 183 participants, 151 (83%) completed the study. The cumulative probability of deterioration was 9% (95% CI = 5% to 14%) by 1 year, 14% (95% CI = 10% to 21%) by 2 years, and 15% (95% CI = 10% to 22%) by 3 years. Of the 25 cases of deterioration by 3 years, 2 had constant XT 10pd or greater at distance and near, 11 had a near stereoacuity decrease of 2 octaves or more from the best previous measure, and 12 started treatment without meeting motor or stereoacuity deterioration criteria (8 were protocol-allowed exceptions). The cumulative probability of meeting the motor or stereoacuity deterioration criteria by 3 years was 8% (95% CI = 5% to 13%).
Over a 3-year period, deterioration of IXT is uncommon among children 3 to 10 years of age with IXT who are observed without treatment. These data on the natural history of childhood IXT provide an important new context for discussions of management between parents and eye care providers.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.
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