Manual corneal thickness measurements of healthy equine eyes using a portable spectral-domain optical coherence tomography device
Article first published online: 9 DEC 2013
© 2013 EVJ Ltd
Equine Veterinary Journal
Volume 46, Issue 5, pages 631–634, September 2014
How to Cite
Pirie, C. G., Alario, A. F., Barysauskas, C. M., Gradil, C. and Uricchio, C. K. (2014), Manual corneal thickness measurements of healthy equine eyes using a portable spectral-domain optical coherence tomography device. Equine Veterinary Journal, 46: 631–634. doi: 10.1111/evj.12198
- Issue published online: 7 AUG 2014
- Article first published online: 9 DEC 2013
- Accepted manuscript online: 17 OCT 2013 12:00AM EST
- Manuscript Accepted: 5 OCT 2013
- Manuscript Received: 20 AUG 2013
- optical coherence tomography;
Reasons for performing study
Corneal thickness measurements of the equine globe using spectral-domain optical coherence tomography (SD-OCT) have not been reported.
To determine corneal thickness measurements and the intra- and interoperator reliability of a portable SD-OCT device in equine eyes.
Prospective observational study.
Horses free of ocular disease were used for this study. Gentle manual restraint, in combination with detomidine hydrochloride and a head stand, were employed to ensure proper animal positioning. Corneal pachymetry measurements were obtained from both eyes of each animal 3 times by 2 operators in succession. A 6 mm corneal pachymetry protocol was performed using a portable SD-OCT device. All measurements were obtained manually by one operator (C.G.P.) using the integrated calliper function. Measurements included epithelial thickness, stromal thickness, Descemet's membrane thickness and total corneal thickness. All recorded measurements were analysed to determine both intra- and interoperator reliability.
Thirty horses with a mean age of 10.6 ± 6.4 years were examined. Mean epithelial, stromal, Descemet's membrane and total corneal thickness values obtained were, respectively, 174.7 ± 13.6, 599.2 ± 45.4, 38.4 ± 15.3 and 812.0 ± 44.1 μm for operator A and 175.9 ± 12.9, 599.2 ± 44.9, 38.4 ± 15.0 and 812.9 ± 42.9 μm for operator B. A positive correlation was found between Descemet's membrane thickness and age, whereby Descemet's membrane thickness increased by 2 μm/year (P<0.0001). The coefficients of variation for both operators were <4% for all measurements. Intraclass correlations ranged from 0.92 to 0.98.
Manual corneal thickness measurement using a portable SD-OCT device provides epithelial, stromal, Descemet's membrane and total corneal thickness measurements with clinically acceptable intra- and interoperator reliability in healthy equine eyes.