Evaluation of equine corneal disease using spectral domain optical coherence tomography (SD-OCT).

PURPOSE

The purpose of this case series is to evaluate the use of spectral domain optical coherence tomography (SD-OCT) imaging in equine corneal disease to demonstrate the feasibility, diagnostic effectiveness, and limitations of this imaging modality.

METHODS

Retrospective study: Handheld SD-OCT (Envisu, Bioptigen Inc, Morrisville, NC) was used for high-resolution imaging of horses with corneal disease presenting to the North Carolina State University Equine Ophthalmology Service from 2013 to 2018.

RESULTS

Fourteen horses were included in this study, including six horses with corneal ulceration, three with stromal abscesses (SA), three with immune-mediated keratitis (IMMK), and two with ocular neoplasms. High-resolution images of the cornea were obtained using handheld SD-OCT in standing horses; however, acquiring images was time-consuming due to the inherent movement of the examiner and horse. Despite this, in horses with corneal ulcers, SA, and IMMK, SD-OCT assisted with determining location of disease in the cornea (eg, superficial, mid-stromal, endothelial) and if disruption of Descemet's membrane was present. In horses with neoplasia, the SD-OCT helped to determine whether the cornea had neoplastic invasion from anterior chamber masses.

CONCLUSIONS

Results from this retrospective study suggest that handheld SD-OCT for imaging the cornea of horses is feasible and may be helpful in determining depth and extent of lesions in the cornea.