A spectral‐domain optical coherence tomography device provides reliable corneal pachymetry measurements in canine eyes

Abstract

The objective of this study was to determine central corneal thickness (CCT) and the intra- and interuser reliability using a portable spectral-domain optical coherence tomography (SD-OCT) device in canine eyes. Twenty clinically normal dogs were examined. CCT measurements were obtained from both eyes of each animal three times by two operators in succession. The CCT was automatically calculated using the pachymetry software generated from eight radial scans, 6 mm in length. Mean canine CCT was 606.83±39.45 μm for all eyes examined. There was no significant difference in CCT based on the eye examined (OD vs OS), age or gender of the animal. There was no significant difference in CCT between replicates performed by the same operator; however, a small but significant difference was noted in CCT between operators. The mean difference in CCT between operators was 1.9 μm (P=0.03). The coefficient of variation for each user and between users was very low (range 0.64-1.7 per cent). The intraclass correlation coefficient comparing operators was 0.975. Based on these results, the SD-OCT device evaluated is capable of obtaining precise CCT measurements with excellent intra- and interoperator reliability in canine eyes.

Spectral‐domain optical coherence tomography evaluation of the cornea, retina, and optic nerve in normal horses

“…Another group of studies has shown the lack of difference of the OCT when compared to the Scheimpflug camera ultrasound pachymetry and optical low‐coherence reflectometry . Independent of those comparisons, SD‐OCT has shown high reliability in obtaining corneal measurements in the human, canine, feline, and equine species …”

“…In the veterinary ophthalmic literature, the use of OCT was first reported in 2007 in a study evaluating retinal structure in the cat and in 2008 to describe the retinopathy of the Coton de Tulear dogs . Recently, several studies have used OCT to characterize the normal cornea, iridocorneal angle, and retina in several species, as well as corneal abnormalities in dogs and cats . In the majority of these studies, the animals were under general anesthesia or deep sedation to avoid eye movement during imaging …”

In vivoevaluation of the cornea and conjunctiva of the normal laboratory beagle using time‐ and Fourier‐domain optical coherence tomography and ultrasound pachymetry

“…Fourier‐domain OCT (FD‐OCT) has also been used for diagnosing and monitoring other anterior segment conditions such as conjunctivochalasis and been used for assessing the tear meniscus of humans . In veterinary ophthalmology, OCT has been primarily used in canine retinal and glaucoma research and there are currently limited data available on OCT values of the canine anterior segment . Studies have found SD‐OCT to be a reliable tool for measuring CCT in dogs …”

“…In veterinary ophthalmology, OCT has been primarily used in canine retinal and glaucoma research and there are currently limited data available on OCT values of the canine anterior segment . Studies have found SD‐OCT to be a reliable tool for measuring CCT in dogs …”

“…Several studies in humans have demonstrated good correlation between corneal thickness measurements obtained by USP and OCT pachymetry . To date, there are only a few publications on USP and OCT corneal pachymetry in dogs . The aims of this study were to obtain images of the cornea using FD‐OCT and TD‐OCT and conjunctiva using FD‐OCT of healthy laboratory beagles and to compare corneal FD‐OCT pachymetry and USP in 3 different locations (superior perilimbal, superior paraxial, and central cornea).…”