1. Collaborative Development of a Care Pathway for
Intermittent Distance Exotropia (IDEX)
Joanne Adeoye1, Patrick McCance2 and Helen Orton1
1.Directorate of Orthoptics and Vision Science, University of Liverpool, 2. Altnagelvin Hospital United Kingdom.
Purpose: To develop an evidence based, collaborative care pathway for the investigation and management of Intermittent Distance Exotropia.
Methods: The University of Liverpool Directorate of Orthoptics and Vision Science was approached by NHS Health Care Trusts of Northern Ireland (NI) to provide a continuing professional development (CPD) with the remit of delivering an update on the current evidence base for the investigation and management of Intermittent Distance Exotropia (IDEX) and to develop a collaborative care pathway.
In 2013 comprehensive literature review was undertaken by University staff utilizing MEDLINE® using the key words ‘exotropia, intermittent, distance, divergence excess, AC/A’. Additionally professional body guidance from Royal College of Ophthalmologists (RCOph) and British & Irish Orthoptic Society (BIOS) was consulted. Utilising the evidence base and information and processes particular to the NI region as a whole and those specific to individual Trusts, a plan for an evidence based care pathway was created during the CPD day, the documentation was subsequently circulated and amended. A flow chart was also produced by NI Orthoptists as a visual representation of the care pathway (Figure 1).
Step
Process
Summary of Evidence
Investigation
AC/A ratio – Gradient for distance and if high (>3:1) repeat following occlusion
Occlusion - CT meas after 30 minutes occlusion
NCS - Parental observations using Newcastle Control Score
Gradient - to eliminate the effect of proximal fusion. Distance to ensure measuring AC/A not C/AC (Horwood & Riddell 2013)
Occlusion - to eliminate the effect of Tenacious Proximal Fusion/ tonic fusion (possible pseudo high AC/A) (Kushner 1998); 30 minutes (Kamlesh 2003);
NCS - to determine need for surgical intervention (Buck 2009);
Management
Observation & Monitoring
Review control/ Observe for progression: CBA,PFR, Stereo, Conv, Meas
Observe for progression - high percentage of patients have no treatment in the first year (Buck 2009); Romanchuck (2006); Holmes (2009)
Optical
Concave lenses – Attempt/ offer in all cases
Prisms - Short-term whilst awaiting surgery or/ signs of decompensation for near
No risk of myopia progression Ekdawi (2010). Effectiveness of using concave lenses (Rowe 2009, Koklanis 2010);
Useful in maintenance of BSV whilst awaiting surgical intervention (Rowe 2009) or to manage post-operative deviations.
Surgery (Sx) –
Indications for Sx – Patient choice, Progression of deviation, in frequency, NCS score to ≥7), Non-response to concave lenses
Choice of Sx – Theoretically:
True – Bilat LR recession MR resection, Simulated – Unilat LR Recession, MR resection, Non Specific – Bilat/ unilateral surgery
Piano et al 2011
Most studies showed similar results with either surgery (Haat & Gnanaraj 2013):
Kushner 1998 found greater success in unilat vs bilat surgery (RCT)
Jeoung 2006
Choi 2012, Wang 2013
Majority of studies consisted of retrospective case reviews.
Figure 1. Care pathway flow chart for Intermittent Distance Exotropia
Conclusions: A systematic approach to this area of practice has enabled a standardised pathway to be devised that takes into account local policies as well as the current evidence base in order for clinicians to have some guidance for practice in this area. The current available literature is of poor quality. Randomised control trials (RCT’s) taking into account natural history and classification of exotropia are needed before robust recommendations can be made.
References
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Choi J et al. The long-term survival analysis of bilateral lateral rectus recession versus unilateral recession-resection for intermittent exotropia. Am J Ophthalmol 2012; 153;
Ekdawi HS, Nusz KJ, Diehl NN and Mohney BG. The development of myopia among children with intermittent exotropia. Am J Ophthalmol 2010; 149 (3).
Hatt SR, Gnanaraj L.Cochrane Database Syst Rev May 31;(5):CD
Holmes JD. Assessment of control in intermittent exotropia. Am Orthop Journal 2009; 59: 5-9
Horwood AM, Riddell PM. Evidence that convergence rather than accommodation controls intermittent distance exotropia. Acta Ophthalmol 2012 Mar;90(2):e109-17
Kamlesh DS. Long-term results of unilateral lateral rectus recession in intermittent exotropia. J Pediatr Ophthalmol Strabismus. 2003 Sep-Oct;40(5):283-7
Koklanis K, Georgievski Z, Zhang K. The use of distance stereoauity assessment in determining the effectiveness of minus lenses in intermittent exotropia.J AAPOS Dec;14(6):488-93
Kushner BJ, Morton GV Distance/near differences in intermittent exotropia. Arch Ophthalmol Apr;116(4):
Piano M et al. Conservative management of intermittent distance exotropia: a review. Am Orthop J 2011;
Romanchuk KG, Dotchin SA, Zurevinsky J. The natural history of surgically untreated intermittent exotropia- looking into the distant future. JAAPOS. 2006 Jun;10(3):
Rowe F et al. Intervention for intermittent distance exotropia with over-correcting minus lenses. Eye 2009: 23;
Kushner BJ. Selective surgery for intermittent exotropia based on distance/ near differences. Archives of Ophthalmology1998;116(3):324-8.
Wang L et al. Comparison of bilateral lateral rectus recession and unilateral recession resection for basic type intermittent exotropia in children. Br J Ophthalmol 2013;97:870–873.