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Vanore M, Benoit-Biancamano MO. Optical Coherence Tomography: A Review of Current Applications in Veterinary Ophthalmology. Vet Clin North Am Small Anim Pract 2023; 53:319-338. [PMID: 36813388 DOI: 10.1016/j.cvsm.2022.10.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
Abstract
Normative standards for healthy animal structures have been established by optical coherence tomography (OCT). OCT has been used in animal studies to characterize more precisely ocular lesions, identify the origin of the affected layer, and eventually provide a curative treatment. To acquire a high image resolution, several challenges must be overcome when performing an OCT scan on animals. Sedation or general anesthesia is usually necessary in OCT image acquisition to alleviate motion during image acquisition. Mydriasis, eye position and movements, head position, and corneal hydration must also be managed during the OCT analysis.
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Affiliation(s)
- Maria Vanore
- Ophthalmology Service, Veterinary Teaching Hospital, Université de Montréal, 3200 Rue Sicotte, Quebec, Canada.
| | - Marie-Odile Benoit-Biancamano
- Department of Pathology and Microbiology, Groupe de Recherche sur les Maladies Infectieuses en Production Animale (GREMIP), Faculté de Médecine Vétérinaire, Université de Montréal, 3200 Rue Sicotte, Quebec, Canada
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Charnock LN, Boveland SD, Groover ES, Moore PA, McMullen RJ. Effects of corneoconjunctival transposition, posterior lamellar keratoplasty and modified deep lamellar endothelial keratoplasty on streak retinoscopy in equine cadaver eyes. Vet Ophthalmol 2022; 25:483-492. [PMID: 36121370 DOI: 10.1111/vop.13025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Revised: 09/06/2022] [Accepted: 09/08/2022] [Indexed: 11/28/2022]
Abstract
OBJECTIVE Evaluate the effects of corneoconjunctival transposition (CCT), posterior lamellar keratoplasty (PLK) and modified deep lamellar endothelial keratoplasty (DLEK) on streak retinoscopy in equine cadaver eyes. METHODS Intraocular pressure (IOP) was maintained at 25 ± 3 mmHg in 35 equine cadaver eyes. Streak retinoscopy was performed prior to (NO VISCO) and following (VISCO) intracameral injection of 1.0 ml of viscoelastic. Following optical coherence tomography (OCT), an axial CCT [n = 11] or PLK [n = 12], or peripheral DLEK [n = 12] was performed. Streak retinoscopy and OCT were repeated postoperatively. RESULTS Postsurgical net meridional and spherical refraction for CCT [Horizontal (H): 3.4 (95% CI 2.4-4.4) diopters (D), p < .001, Vertical (V): 3.5 (95% CI 2.7-4.4) D, p < .001, Spherical: 3.5 (95% CI 2.6-4.3) D, p < .001] and PLK [H: 3.2 (95% CI 2.2-4.1) D, p < .001, V: 2.8 (95% CI 2.0-3.6) D, p < .001, Spherical: 3.0 (95% CI 2.2-3.8) D, p < .001] were significantly increased from presurgical (VISCO) values. No difference between presurgical (VISCO) and postsurgical values were identified for the DLEK. Postoperative OCT revealed space between anterior and posterior corneal grafts and corneal undulation associated with suture placement. CONCLUSION Meridional and spherical refraction had a hyperopic shift following CCT and PLK, with a significantly higher value in the vertical meridian for the CCT. Pre- and postoperative refraction was not significantly different for the DLEK. This supports that the DLEK has a lesser effect on immediate postoperative refraction compared with CCT or PLK.
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Affiliation(s)
- Lauren N Charnock
- College of Veterinary Medicine, Auburn University, Auburn, Alabama, USA
| | | | - Erin S Groover
- College of Veterinary Medicine, Auburn University, Auburn, Alabama, USA
| | - Phillip A Moore
- College of Veterinary Medicine, Auburn University, Auburn, Alabama, USA
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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; 25 Suppl 1:17-24. [PMID: 35084084 PMCID: PMC9246829 DOI: 10.1111/vop.12971] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2021] [Revised: 01/10/2022] [Accepted: 01/15/2022] [Indexed: 11/30/2022]
Abstract
OBJECTIVE To determine corneal thickness (CT) and axial anterior chamber depth (ACD) using ultrasound biomicroscopy (UBM) in normal adult horses. To compare corneal thickness measurements between UBM and ultrasonic pachymetry. ANIMALS STUDIED Sixty eyes of 30 healthy adult horses aged 8-24 years. PROCEDURES Ultrasonic pachymetry (velocity of 1640 m/s) was utilized to obtain measurements of the central, superior, temporal, inferior, and nasal cornea. Triplicate images of the same corneal locations were acquired using UBM (50 MHz). Images of the axial anterior chamber were used to measure ACD. Intraocular pressure (IOP) was estimated using rebound tonometry, and axial globe length was measured using ultrasonographic biometry. RESULTS CT (mean ± SD µm) measured by UBM was 854 ± 61 (central), 994 ± 58 (superior), 930 ± 57 (temporal), 979 ± 55 (inferior), and 898 ± 48 (nasal). CT measured by UBM was greater than that measured by ultrasonic pachymetry at all locations and was statistically significant at all locations except inferior (p = 0.0006-0.048). No sex nor age effect was detected for CT at any location. The repeatability of ultrasonic pachymetry was superior to that of UBM. Mean ± SD ACD was 5.74 ± 0.41 mm. A weak positive correlation was identified between central CT and IOP and between central CT and axial globe length. CONCLUSIONS Normal data for CT and ACD of the adult horse obtained using UBM are provided. CT determined by UBM was greater relative to pachymetry at all corneal locations.
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Affiliation(s)
- Kelly E Knickelbein
- Veterinary Medical Teaching Hospital, University of California-Davis, Davis, California, USA
| | - Mary E Lassaline
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California-Davis, Davis, California, USA
| | - Soohyun Kim
- Veterinary Medical Teaching Hospital, University of California-Davis, Davis, California, USA
| | - Machal S Scharbrough
- School of Veterinary Medicine, University of California-Davis, Davis, California, USA
| | - Sara M Thomasy
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California-Davis, Davis, California, USA.,Department of Ophthalmology and Vision Science, University of California-Davis, Davis, California, USA
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Hefner EM, Lin HC, Cole RC, Moore PA, McMullen RJ. Comparison of image quality of corneal and retinal optical coherence tomography using sedation and general anesthesia protocols with or without retrobulbar anesthesia in horses. Am J Vet Res 2021; 83:72-79. [PMID: 34727049 DOI: 10.2460/ajvr.21.02.0029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To compare image quality and acquisition time of corneal and retinal spectral domain optical coherence tomography (SD-OCT) under 3 different sedation-anesthesia conditions in horses. ANIMALS 6 middle-aged geldings free of ocular disease. PROCEDURES 1 randomly selected eye of each horse was evaluated via SD-OCT under the following 3 conditions: standing sedation without retrobulbar anesthetic block (RB), standing sedation with RB, and general anesthesia with RB. Five regions of interest were evaluated in the cornea (axial and 12, 3, 6, and 9 o'clock positions) and fundus (optic nerve head). Three diagnostic scans of predetermined quality were obtained per anatomical region. Image acquisition times and total scans per site were recorded. Corneal and retinal SD-OCT image quality was graded on a subjective scale from 0 (nondiagnostic) to 4 (excellent). RESULTS Mean values for the standing sedation without RB, standing sedation with RB, and general anesthesia conditions were 24, 23, and 17, respectively, for total cornea scan attempts; 23, 19, and 19 for total retina-scan attempts; 14.6, 13.2, and 9.2 minutes for total cornea scan time; 19.1, 9.2, and 13.0 for total retina scan time; 2.0, 2.3, and 2.5 for cornea grade; and 2.7, 2.9, and 2.5 for retina grade. CONCLUSIONS AND CLINICAL RELEVANCE The RB facilitated globe akinesia and improved the percentage of scans in frame and region of interest accuracy for retinal imaging via OCT in horses. Retrobulbar blocks improved clinical image acquisition while minimizing motion artifact.
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Keenan AV, Townsend WM. Evaluation of equine corneal disease using ultrasound biomicroscopy. Vet Ophthalmol 2021; 25 Suppl 1:179-184. [PMID: 33694251 DOI: 10.1111/vop.12881] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 12/09/2020] [Accepted: 02/15/2021] [Indexed: 01/20/2023]
Abstract
OBJECTIVE To describe the clinical use of ultrasound biomicroscopy (UBM) to evaluate equine corneal disease. METHODS Images were obtained using a 50-MHz probe ultrasound biomicroscopy system (Quantel Aviso) and Clear Scan® probe cover. Six horses with corneal disease were evaluated via UBM for lesion size, lesion depth, and continuity of Descemet's membrane. Horses were sedated and received auriculopalpebral nerve blocks and application of topical anesthetic prior to UBM. RESULTS Ultrasound biomicroscopy was easily performed in all cases. UBM evaluation of three cases of corneo-limbal squamous cell carcinoma yielded information regarding lesion depth for planning of keratectomies using fixed-depth keratomes and subsequent β-radiation therapy. Corneal depth and continuity of Descemet's membrane were determined in two horses with stromal abscesses and allowed for planning of therapeutic options. In one horse with a corneal foreign body, UBM contributed to accurate assessment of the foreign body's stromal depth, which could not be assessed during ophthalmic examination due to extensive corneal cellular infiltrate. The information regarding corneal depth allowed for more accurate pre-surgical planning in patients with opaque corneal lesions. CONCLUSIONS Ultrasound biomicroscopy was easily performed and provided useful information regarding lesion depth and continuity of Descemet's membrane for patients with corneo-limbal squamous cell carcinoma, stromal abscesses, and a corneal foreign body, allowing for increased precision in pre-surgical planning and development of therapeutic protocols.
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Affiliation(s)
- Alessandra V Keenan
- Department of Clinical Sciences, Auburn University College of Veterinary Medicine, Auburn, AL, USA
| | - Wendy M Townsend
- Department of Veterinary Clinical Sciences, Purdue University College of Veterinary Medicine, West Lafayette, IN, USA
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Blanchard A, Barr EM, Gilger BC. Evaluation of equine corneal disease using spectral domain optical coherence tomography (SD‐OCT). Vet Ophthalmol 2019; 22:791-798. [DOI: 10.1111/vop.12652] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 01/21/2019] [Accepted: 01/24/2019] [Indexed: 01/17/2023]
Affiliation(s)
- Allison Blanchard
- Equine Ophthalmology Service North Carolina State University College of Veterinary Medicine Raleigh North Carolina
| | - Erin M. Barr
- Equine Ophthalmology Service North Carolina State University College of Veterinary Medicine Raleigh North Carolina
| | - Brian C. Gilger
- Equine Ophthalmology Service North Carolina State University College of Veterinary Medicine Raleigh North Carolina
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Jiao H, Hill LJ, Downie LE, Chinnery HR. Anterior segment optical coherence tomography: its application in clinical practice and experimental models of disease. Clin Exp Optom 2018; 102:208-217. [PMID: 30270476 DOI: 10.1111/cxo.12835] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 08/13/2018] [Accepted: 08/13/2018] [Indexed: 12/19/2022] Open
Abstract
Optical coherence tomography (OCT) provides non-invasive, high-resolution in vivo imaging of the ocular surface and anterior segment. Over the years, it has become an essential tool for evaluating the anterior segment of the eye to monitor ocular development and ocular pathologies in both the clinical and research fields of ophthalmology and optometry. In this review, the clinical applications relating to the use of anterior segment OCT for imaging and quantifying normal and pathological features of the ocular surface, cornea, anterior chamber, and aqueous outflow system are summarised in a range of human ocular diseases. Applications of anterior segment OCT technology that have improved imaging and quantitation of ocular inflammation in experimental animal models of ocular diseases, such as anterior uveitis, microbial keratitis and glaucoma, are also described. The capacity to longitudinally evaluate anterior segment anatomical changes during development, and inflammation facilitates the understanding of the dynamics of tissue responses, and further enhances the intra-operative in vivo imaging during procedures, such as corneal transplantation and drug delivery. Future developments including in vivo ultrahigh-resolution anterior segment OCT, automated analyses of anterior segment OCT images and functional extensions of the technique, may revolutionise the clinical evaluation of anterior segment, corneal and ocular surface diseases.
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Affiliation(s)
- Haihan Jiao
- Department of Optometry and Vision Sciences, The University of Melbourne, Parkville, Victoria, Australia
| | - Lisa J Hill
- Institute of Clinical Sciences, University of Birmingham, Birmingham, UK
| | - Laura E Downie
- Department of Optometry and Vision Sciences, The University of Melbourne, Parkville, Victoria, Australia
| | - Holly R Chinnery
- Department of Optometry and Vision Sciences, The University of Melbourne, Parkville, Victoria, Australia
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Abstract
This article reviews the literature for studies describing advanced imaging of the equine eye as a reference for practitioners to help in the selection of image modalities, describe how to use the instruments, and help interpret the image findings. Indications for, technique of, and image interpretation of advanced image modalities such as ultrasound, computed tomography, MRI, optical coherence tomography, confocal microscopy, and angiography are reviewed. The article is organized anatomically, not by instrument, so that the reader will be able to quickly research ways to image specific disease entities or anatomic locations that are affecting their equine patients.
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Affiliation(s)
- Brian C Gilger
- Department of Clinical Sciences, NC State University College of Veterinary Medicine, 1060 William Moore Drive, Raleigh, NC 27607, USA.
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LoPinto AJ, Pirie CG, Bedenice D, Ayres SL. Corneal thickness of eyes of healthy goats, sheep, and alpacas manually measured by use of a portable spectral-domain optical coherence tomography device. Am J Vet Res 2017; 78:80-84. [DOI: 10.2460/ajvr.78.1.80] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Gornik KR, Pirie CG, Marrion RM, Wocial JN, Innis CJ. Ophthalmic variables in rehabilitated juvenile Kemp's ridley sea turtles(Lepidochelys kempii). J Am Vet Med Assoc 2016; 248:673-80. [DOI: 10.2460/javma.248.6.673] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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