The Improving Outcomes in Intermittent Exotropia Study: 2 Year Outcomes

Abstract

Purpose: : The UK Improving Outcomes in Intermittent Exotropia Study is a pragmatic, multicentre, observational cohort study which aims to improve the effectiveness and efficiency of intermittent exotropia X(T) management.

Methods: : Between May 2005 -December 2006, 26 participating departments in the UK recruited children, less than 12 years old, newly diagnosed with X(T). Treatment was at the discretion of the local clinician. Participants were reviewed at 3 monthly intervals. Outcomes at 24 months (no surgery) or at 6 and 12 months post surgery are reported.BU 460 children were recruited. Within 24 months of recruitment, 252 received no treatment; 112 were treated for impaired visual acuity; 129 received treatment specifically for X(T) (60 non surgical; 69 surgical). In children having surgery, median X(T) control (measured with the Newcastle Control Score [NCS]) improved significantly both at 6-months (p<0.001) and 12-months (p<0.001) post-surgery. Improvements in control were less marked in those having non-surgical treatment (p<0.03). There were no significant improvements in control in observed children or those having treatment only for impaired acuity. 3 surgical patients had Botulinum toxin injections for overcorrection within 6 months of surgery. At 6 months post surgery, 22% remained overcorrected (15% at 12 months). Only 3 patients progressed to constant exotropia within 24-months of recruitment (in all groups).

Conclusions: : Surgery was more likely to produce improvement or cure than other treatments during the follow up period, however rates of overcorrection were significant. Rates of progression to constant exotropia have previously been overestimated. A randomised trial is needed to refine the indications for surgery in X(T).

Keywords: esotropia and exotropia • clinical (human) or epidemiologic studies: outcomes/complications • strabismus: treatment