Anterior segment - optical coherence tomography (AS-OCT) is a non-contact imaging method that can provide accurate measures of extraocular muscles to limbus insertion distances. The authors evaluated the accuracy of AS-OCT for locating horizontal extraocular muscle insertions after strabismus surgery in 31 muscles of 28 patients (20 female) aged 46 ±15 years. Results were for 14 medial and 17 lateral rectus muscles. Muscle insertion was identified on AS-OCT for 14 eye muscles of 13 patients. Average measurements for non-identified muscles were 12mm and 7.5mm for identifiable muscles; a significant difference. Intraclass correlation between AS-OCT and surgical measures was 0.771; 0.668 for lateral rectus and 0.879 for medial rectus. The authors found AS-OCT was able to measure muscle insertion location in just 45%. This may be due to use in acute postoperative settings in the presence of postoperative tissue swelling. Accurate measures were obtained where insertions were less than 8mm from the limbus. They acknowledge the limitations of this study such as small number of measurements and different measurement units between calliper use and AS-OCT. They recommend further larger scale studies.
