Spectral-domain optical coherence tomography evaluation of the cornea, retina, and optic nerve in normal horses.
Abstract: To determine the feasibility of using a handheld spectral-domain optical coherence tomography (SD-OCT) instrument to characterize normal corneal, retinal, and optic nerve head anatomy in vivo in standing horses. Methods: Clinically normal horses under sedation, palpebral nerve blockage, and pharmacologically induced mydriasis were imaged with a SD-OCT instrument (Envisu SD-OCT, Bioptigen, Inc., Morrisville, NC). Radial volumes from the cornea (axial, superior, inferior, nasal, and temporal), and rectangular volumes from the retina (dorsal, ventral, nasal, and temporal) and optic nerve head were acquired. Manual measurements of the corneal layers within the five regions, retinal and nerve fiber layer thickness in the four different regions adjacent to the ONH, and vertical and horizontal axis of the optic nerve head (ONH) and optic cup (OC) were obtained using the same device. Results: Total corneal thickness (mean ± SD) measurements were 800 ± 50, 937 ± 61, 956 ± 61, 912 ± 65, and 884 ± 68 μm for the axial, superior, inferior, nasal, and temporal regions, respectively. The highest total retinal and nerve fiber layer thickness (mean ± SD), at the level of the ONH, was found nasally 459 ± 115 and 377 ± 116 μm, respectively, followed by the temporal, dorsal, and ventral quadrants. The dimensions of the ONH and OC (mean ± SD) were 3.682 ± 0.276 and 2.175 ± 0.502 mm for the horizontal, and 3.012 ± 0.278 and 2.035 ± 0.488 mm for the vertical axis. Conclusions: The SD-OCT instrument employed in this study may be used on sedated horses and allows the acquisition of high-resolution images, and thickness measurements involving the cornea, retina, and optic nerve.
© 2014 American College of Veterinary Ophthalmologists.
Publication Date: 2014-05-14 PubMed ID: 24824940DOI: 10.1111/vop.12180Google Scholar: Lookup
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- Journal Article
Summary
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Research in brief: The study demonstrates that a portable Spectral-domain Optical Coherence Tomography (SD-OCT) instrument can be effectively used to obtain high-resolution images and measurements of the cornea, retina, and optic nerve head in horses.
Research details and methods
- The research explored the feasibility of using a handheld spectral-domain optical coherence tomography (SD-OCT) to analyze the standard corneal, retinal, and optic nerve head makeup in horses.
- For the experiment, only clinically normal horses were used who were sedated and subjected to a blocking procedure of a nerve in their eyelids (palpebral) to disable blinking, along with the pharmacological induction of mydriasis (dilation of pupils).
- The SD-OCT instrument used was Envisu from Bioptigen, Inc., which was used to acquire ‘volumes’ from the cornea, the retina, and the head of the optic nerve.
- Subsequently, manual measurements were taken for the cornea layers within the five studied regions, the thickness of the retinal and nerve fiber layer in four different areas near the optic nerve head (ONH), and the vertical and horizontal axis of the ONH and optic cup (OC).
Research findings
- The thickness of the corneal area was found to be different in different regions with the inferior region having the maximum thickness.
- The nasal region of the retina and nerve fiber layer thickness was found to be highest.
- The dimensions of the optic nerve head and optic cup also varied for vertical and horizontal axis.
Research implications and conclusions
- The findings confirm that the SD-OCT instrument can be effectively used on sedated horses, providing high-resolution images and thickness measurements involving the cornea, retina, and optic nerve.
- The results of the study could potentially change the way these anatomical structures in horses are examined, providing a more efficient non-invasive technique to veterinary ophthalmology.
Cite This Article
APA
Pinto NI, Gilger BC.
(2014).
Spectral-domain optical coherence tomography evaluation of the cornea, retina, and optic nerve in normal horses.
Vet Ophthalmol, 17 Suppl 1, 140-148.
https://doi.org/10.1111/vop.12180 Publication
Researcher Affiliations
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, 27606, USA.
MeSH Terms
- Animals
- Cornea / anatomy & histology
- Feasibility Studies
- Female
- Horses / anatomy & histology
- Male
- Optic Nerve / anatomy & histology
- Retina / anatomy & histology
- Tomography, Optical Coherence / veterinary
Citations
This article has been cited 2 times.- Knickelbein KE, Lassaline ME, Kim S, Scharbrough MS, Thomasy SM. Corneal thickness and anterior chamber depth of the normal adult horse as measured by ultrasound biomicroscopy. Vet Ophthalmol 2022 May;25 Suppl 1(Suppl 1):17-24.
- Ostendarp C, Barton AK. Intraocular Tumors in Horses: Diagnosis, Tumor Classification, Oncologic Assessment and Therapy. Vet Sci 2025 Oct 17;12(10).
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