Corneal thickness of eyes of healthy goats, sheep, and alpacas manually measured by use of a portable spectral-domain optical coherence tomography device

Alexander J. LoPinto Department of Clinical Sciences, Cummings School of Veterinary Medicine, Tufts University, North Grafton, MA 01536.

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Chris G. Pirie Department of Clinical Sciences, Cummings School of Veterinary Medicine, Tufts University, North Grafton, MA 01536.

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Daniela Bedenice Department of Clinical Sciences, Cummings School of Veterinary Medicine, Tufts University, North Grafton, MA 01536.

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Sandra L. Ayres Department of Biomedical Sciences, Cummings School of Veterinary Medicine, Tufts University, North Grafton, MA 01536.

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Abstract

OBJECTIVE

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.

ANIMALS

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

PROCEDURES

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.

RESULTS

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.

CONCLUSIONS AND CLINICAL RELEVANCE

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.

Abstract

OBJECTIVE

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.

ANIMALS

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

PROCEDURES

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.

RESULTS

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.

CONCLUSIONS AND CLINICAL RELEVANCE

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.

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