Audit of Inferior Oblique Weakening Surgery to Determine Impact on Horizontal Alignment
Yesa Yang; Maria Theodorou; Clare Roberts; James Acheson; Gill Adams
Moorfields Eye Hospital
London, United Kingdom
Introduction: It has been reported that surgery for inferior oblique weakening surgery (IOOA-) can cause a modest eso-shift but does not significantly impact horizontal alignment in primary position1,2. An audit was undertaken to determine our clinical data on the impact of IOOA- on horizontal alignment.
Methods: A retrospective casenotes review of patients who underwent IOOA- between March 2014 and March 2016 in our department was conducted. There were 106 patients (57 male, 49 female), of which 43 were under 16 years. Collected data included patient characteristics, surgery technique, pre and post-surgery vertical and horizontal deviations as well as extent of inferior oblique overaction(IOOA).
Results: Average patient age was 28 years (range 2 to 75 years); 76 procedures were unilateral, 30 were bilateral. There were 43 disinsertions; 24 myectomies; 28 recessions; 11 anterior transpositions. Mean change in horizontal alignment (both near and distance) for each subcategory was within 8 prism diopters (PD), although this masked a wide range (up to 55PD eso-shift and up to 20PD exo-shift). Overall 16% of patients had a change of 10PD or more in horizontal alignment following IOOA-.
Discussion: Our audit demonstrated a wide range of changes to the horizontal alignment affecting a small proportion of patients, particularly those with moderate pre-existing horizontal deviations.
Conclusion: Given the potential unpredictability, this would support the clinical practice for considering two stage surgeries (IOOA-, followed by horizontal surgery) for patients with IOOA in the presence of moderate horizontal deviations.
References: 1. Stager DR, Parks MM. Inferior Oblique Weakening Procedures. Effect on Primary Position Horizontal Alignment. Arch Ophthalmol. 1973;90:15-16.
2. Sekeroglu HT, Dikmetas O, Sanac AS et al, Inferior Oblique Muscle Weakening: Is it Possible to Quantify Its Effects on Horizontal Deviations? J Ophthalmol 2012: 813085. doi:10.1155/2012/813085