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Logo of bmcophtBioMed Centralsearchsubmit a manuscriptregisterthis articleBMC Ophthalmology
BMC Ophthalmol. 2012; 12: 1.
Published online Jan 18, 2012. doi:  10.1186/1471-2415-12-1
PMCID: PMC3293086
The improving outcomes in intermittent exotropia study: outcomes at 2 years after diagnosis in an observational cohort
Deborah Buck,corresponding author1 Christine J Powell,2 Jugnoo Rahi,3 Phillippa Cumberland,3 Peter Tiffin,4 Robert Taylor,5 John Sloper,6 Helen Davis,7 Emma Dawson,6 and Michael P Clarke1,2
1Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, UK
2Royal Victoria Infirmary Eye Dept, Newcastle upon Tyne Hospitals NHS Trust, UK
3Institute of Child Health, University College London, UK
4Sunderland Eye Infirmary, Sunderland, UK
5York Hospitals NHS Trust, York, UK
6Moorfields Eye Hospital, London, UK
7Academic Unit of Ophthalmology and Orthoptics, University of Sheffield, Sheffield, UK
corresponding authorCorresponding author.
Deborah Buck: Deborah.Buck/at/; Christine J Powell: Christine.Powell2/at/; Jugnoo Rahi: j.rahi/at/; Phillippa Cumberland: p.cumberland/at/; Peter Tiffin: petertiffin/at/; Robert Taylor: Robert.Taylor/at/York.NHS.UK; John Sloper: john.sloper/at/; Helen Davis: h.davis/at/; Emma Dawson: Emma.Dawson/at/; Michael P Clarke: Michael.Clarke/at/
Received May 24, 2011; Accepted January 18, 2012.
The purpose of this study was to investigate current patterns of management and outcomes of intermittent distance exotropia [X(T)] in the UK.
This was an observational cohort study which recruited 460 children aged < 12 years with previously untreated X(T). Eligible subjects were enrolled from 26 UK hospital ophthalmology clinics between May 2005 and December 2006. Over a 2-year period of follow-up, clinical data were prospectively recorded at standard intervals from enrolment. Data collected included angle, near stereoacuity, visual acuity, control of X(T) measured with the Newcastle Control Score (NCS), and treatment. The main outcome measures were change in clinical outcomes (angle, stereoacuity, visual acuity and NCS) in treated and untreated X(T), 2 years from enrolment (or, where applicable, 6 months after surgery). Change over time was tested using the chi-square test for categorical, Wilcoxon test for non-parametric and paired-samples t-test for parametric data.
At follow-up, data were available for 371 children (81% of the original cohort). Of these: 53% (195) had no treatment; 17% (63) had treatment for reduced visual acuity only (pure refractive error and amblyopia); 13% (50) had non surgical treatment for control (spectacle lenses, occlusion, prisms, exercises) and 17% (63) had surgery. Only 0.5% (2/371) children developed constant exotropia. The surgically treated group was the only group with clinically significant improvements in angle or NCS. However, 8% (5) of those treated surgically required second procedures for overcorrection within 6 months of the initial procedure and at 6-month follow-up 21% (13) were overcorrected.
Many children in the UK with X(T) receive active monitoring only. Deterioration to constant exotropia, with or without treatment, is rare. Surgery appears effective in improving angle of X(T) and NCS, but rates of overcorrection are high.
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