Comparison of the accuracy of anterior segment optical coherence tomography and ultrasound biomicroscopy in localizing rectus muscle insertions.
Arash Mir Mohammad Sadeghi1 *, Nikoo Hamzeh1 , Fariba Ghassemi1 , Mohammad Reza Akbari1
- Eye Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran.
Abstract: To compare the accuracy of anterior segment optical coherence tomography (AS-OCT) and ultrasound biomicroscopy (UBM) in localizing rectus muscle insertions.
Methods: The study was performed on 27 patients (39 rectus muscles) who required primary or secondary surgery. Using caliper function in the AS-OCT and UBM software, the distance from the insertion site to the anterior chamber angle was measured. The actual muscle insertion distance from limbus was considered as the measured distance plus 1 mm. The measurements by UBM and AS-OCT were compared with intraoperative measurements and with each other.
Results: AS-OCT and UBM were performed on 13 medial rectus, 24 lateral rectus, and 2 superior rectus muscles. At the surgery, the mean distance of insertion from limbus was 7.0 ± 0.9 (4-9) mm. Ninety two percent of UBM measurements (36 muscles) were within 1 mm, one was within 1-1.5 mm, and 2 were within 1.5-2 mm of surgery measurements. Eighty five percent of AS-OCT measurements (33 muscles) were within 1 mm, 5 were within 1-1.5 mm, and one was within 1.5-2 mm of surgery measurements. In all cases, the mean absolute error of the UBM (0.54 ± 0.44) and AS-OCT (0.51 ± 0.36) showed no significant difference (p= 0.76), but the mean absolute error of the UBM was significantly more than that of AS-OCT in the esotropia subgroup (p= 0.03).
Conclusion: AS-OCT and UBM can be used interchangeably to localize rectus muscle insertions and showed good agreements with surgery. AS-OCT was superior to UBM in the esotropia cases.
