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  • Author or Editor: Sandra L. Ayres x
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To determine corneal thickness of eyes of healthy goats, sheep, and alpacas by use of a portable spectral-domain optical coherence tomography (SD-OCT) device and evaluate intraoperator reliability for measurements.


11 female goats, 10 female sheep, and 11 (4 males and 7 females) alpacas.


Each animal was sedated, and gentle manual restraint was used to ensure proper positioning of the head and globe. Corneal pachymetry was performed (in triplicate) with a portable SD-OCT device on both eyes of each animal. All corneal measurements were obtained manually by use of the integrated caliper function. Corneal epithelial thickness (CET), corneal stromal thickness (CST), Descemet membrane thickness (DMT), and total corneal thickness (TCT) were measured twice on each image, and a mean value was calculated.


Mean ± SD values for CET, CST, DMT, and TCT were 96.1 ± 5.0 μm, 486.0 ± 10.3 μm, 36.8 ± 4.8 μm, and 616.9 ± 7.1 μm, respectively, for the goats; 111.6 ± 5.7 μm, 599.8 ± 10.0 μm, 31.0 ± 4.5 μm, and 741.1 ± 9.9 μm, respectively, for the sheep; and 147.4 ± 5.7 μm, 446.1 ± 7.4 μm, 44.5 ± 5.0 μm, and 634.8 ± 6.2 μm, respectively, for the alpacas. Intraclass correlations ranged from 0.49 to 0.83 for CET, CST, and TCT and from 0.13 to 0.36 for DMT.


SD-OCT provided manual measurement of corneal thickness (CET, CST, and TCT) with clinically acceptable intraoperator reliability for eyes of healthy goats, sheep, and alpacas.

Full access
in American Journal of Veterinary Research


OBJECTIVE To compare results of anterior segment angiography of ophthalmically normal eyes of goats, sheep, and alpacas performed by use of indocyanine green (ICG) and sodium fluorescein (SF).

ANIMALS 10 female goats (mean ± SD age, 6.8 ± 1.7 years), 10 female sheep (3.0 ± 2.2 years), and 10 alpacas (7 females and 3 males; 6.8 ± 3.8 years).

PROCEDURES A catheter was aseptically placed into a jugular vein. Each animal was anesthetized and properly positioned, and 0.25% ICG was administered. Images were obtained by use of an adaptor system consisting of a modified digital single-lens reflex camera, camera adaptor, and camera lens. Images were obtained at a rate of 3 images/s for the 60 seconds immediately after ICG administration and then at 2, 3, 4, and 5 minutes after administration. Ten minutes later, 10% SF was administered IV and images were obtained in a similar manner.

RESULTS Angiography with ICG provided visual examination of the arterial, capillary, and venous phases in all species. Visual examination of the iris vasculature by use of SF was performed in goats and sheep but was not possible in the alpacas because of iridal pigmentation. Extravasation of SF was a common finding in sheep and alpacas but not in goats. No adverse events were detected.

CONCLUSIONS AND CLINICAL RELEVANCE Quality angiographic images of the anterior segment were obtainable after IV administration of ICG to goats, sheep, and alpacas. This may provide a useful imaging modality for ocular research in these animal species.

Full access
in American Journal of Veterinary Research