J Vet Sci.  2023 Jul;24(4):e34. 10.4142/jvs.22241.

Inter-device agreement between spectral domain optical coherence tomography, ultrasound biomicroscopy, and gonioscopy in evaluating the iridocorneal angle in normotensive dogs

• Kim SA
• Shim J
• Kang S
• Seo K

• KMID: 2545105
• DOI: http://doi.org/10.4142/jvs.22241

Abstract

Background
There has not been a thoroughly reported study of the comparison between spectral domain-optical coherence tomography (SD-OCT) with both ultrasound biomicroscopy (UBM) and gonioscopy on the evaluation of the iridocorneal angle (ICA) in dogs.
Objectives
To investigate the diagnostic value of SD-OCT for the early detection of narrowing ICA by comparing and assessing inter-device agreement in anterior chamber angle (ACA) measurements obtained by SD-OCT and UBM, and ICA evaluations by gonioscopy.
Methods
A total of 28 eyes from 28 client-owned dogs with normal intraocular pressure were included for examination. The ACA and angle opening distance (AOD) were measured from the SD-OCT and UBM images, and gonioscopy images were analyzed using the ICA grade and ZibWest angle index.
Results
The mean ACA and AOD for SD-OCT were 28.31° ± 5.37° and 658.42 ± 219.90 µm, and for UBM, 28.34° ± 5.82° and 859.29 ± 221.80 µm, respectively. The mean difference in ACA between the average values of SD-OCT and UBM measurements was 0.03° with a 95% limit of agreement (LoA) span of 16.2°, indicating positive agreement; that in AOD was 200.85 µm with a 95% LoA span of 1,110.95 µm, indicating poor agreement. The Pearson correlation coefficient of the ACA of SD-OCT and ZibWest indices of gonioscopy was 0.624, indicating strong agreement; that of UBM and gonioscopy was 0.43, indicating moderate agreement.
Conclusions
SD-OCT is well tolerated by canine patients due to its non-contact method and might be an alternative option for early screening of ICA narrowing in clinical settings.

Keyword

Diagnosis; glaucoma; mass screening; optical imaging; therapeutics