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Knickelbein KE, Lassaline ME, Kim S, Thomasy SM. Ultrasound biomicroscopy of the equine iridocorneal angle. Equine Vet J 2022; 54:1153-1158. [PMID: 35568989 PMCID: PMC9547819 DOI: 10.1111/evj.13585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 03/12/2022] [Accepted: 05/05/2022] [Indexed: 11/29/2022]
Abstract
BACKGROUND The iridocorneal angle (ICA) is the major pathway of aqueous humour outflow from the anterior chamber of the eye. Ultrasound biomicroscopy (UBM) has been utilised to characterise the morphology of this drainage pathway in numerous species. UBM may allow for early recognition of aqueous humour outflow obstructions in horses, allowing for earlier recognition of risk for glaucoma, a vision-threatening and painful disease. UBM morphology of the normal equine ICA has yet to be described. OBJECTIVES To determine the ultrasonographic morphology of the equine ICA by UBM in standing sedated horses. STUDY DESIGN In vivo experimental study. METHODS Thirty healthy adult horses underwent UBM of the ICA at four locations (superior, temporal, inferior, nasal) of each eye utilising standing sedation, topical anaesthesia and auriculopalpebral perineural anaesthesia. Anatomic structures were defined on ultrasound images through comparison to published histologic photomicrographs of the equine ICA. RESULTS Ultrasound imaging of the ICA at all four locations was easily performed in standing, sedated horses. High-resolution images of the ICA allowed for identification of the pectinate ligament, corneoscleral trabecular meshwork (TM), uveal TM and supraciliary TM. MAIN LIMITATIONS Pupil size was midrange in all eyes, but was not strictly controlled. Lighting conditions not controlled. Various breeds included. CONCLUSION In vivo UBM of the equine ICA is feasible and provides high-resolution images of the structures of the aqueous humour outflow pathway.
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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
| | - 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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Rodriguez Galarza RM, McMullen RJ. Descemet's membrane detachments, ruptures, and separations in ten adult horses: Clinical signs, diagnostics, treatment options, and preliminary results. Vet Ophthalmol 2020; 23:611-623. [PMID: 32529665 DOI: 10.1111/vop.12793] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Revised: 04/27/2020] [Accepted: 05/15/2020] [Indexed: 12/18/2022]
Abstract
OBJECTIVE To describe the clinical presentation, diagnostic imaging results, and treatment outcomes of a series of presumed spontaneous Descemet's membrane detachments (DMD), ruptures, or separations (DMRS) in the adult horse. ANIMALS STUDIED Ten adult horses of various breeds with DMD or DMRS. PROCEDURES Descemet's membrane detachments/DMRS were diagnosed via slit lamp biomicroscopy, ultrasound biomicroscopy (UBM), and/or optical coherence tomography (OCT). Penetrating keratoplasty (PK) with heterologous corneal donor tissue (n = 1), superficial lamellar keratectomy, and Gundersen inlay flaps alone (GF, n = 1) or with subsequent intracamerally assisted corneal tissue welding (CTW, n = 2), or CTW alone (n = 5) were performed in 9/10 horses. One horse underwent spontaneous resolution (n = 1). RESULTS Ten horses were diagnosed with either unilateral DMD (n = 4) or DMRS (n = 6). Seven of ten eyes remained visual during the follow-up period (8.16 ± 6.57 months). Graft transparency was good for the eye treated with PK. The horse that underwent GF alone was functionally blind due to persistent corneal edema. The clinical signs resolved in 3/5 horses that underwent CTW alone, but 2/5 eyes were enucleated due to corneal perforation. Both eyes treated with combined GF/CTW had significant corneal clearing with one having evidence of reattachment on UBM and OCT. CONCLUSIONS Descemet's membrane detachments separations presents differently than typical DMD and advanced corneal imaging modalities may aid in their diagnosis. Corneal tissue welding using infraCG as the photosensitive agent, or in combination with Gundersen inlay flaps, represents a feasible treatment option for management of equine DMD/DMRS as described in the present case series.
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Affiliation(s)
| | - Richard J McMullen
- JT Vaughan Large Animal Teaching Hospital, Auburn University College of Veterinary Medicine, Auburn, AL, USA
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Flores MM, Del Piero F, Habecker PL, Langohr IM. A retrospective histologic study of 140 cases of clinically significant equine ocular disorders. J Vet Diagn Invest 2020; 32:382-388. [PMID: 32207378 DOI: 10.1177/1040638720912698] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Ocular diseases are an important category in equine medicine; however, most articles regarding histologic ocular lesions in horses are exclusive to a specific condition and do not provide a complete review of clinically significant ocular disease frequency in a diagnostic laboratory. We reviewed sections of equine eyes from 140 cases (98 enucleations [biopsies] and 42 autopsies) with clinically relevant ocular alterations at 2 diagnostic centers in the United States. The most common primary conditions were non-traumatic keratitis (36), equine recurrent uveitis (ERU; 31), traumatic injuries (22), ocular and periocular neoplasms (19), and uveitis and/or endophthalmitis resulting from sepsis (18). Congenital anomalies (3) and retinal atrophy and detachment alone (3) were infrequent. Non-traumatic keratitis was frequently accompanied by anterior uveitis (22), corneal rupture (16), pre-iridal fibrovascular membrane formation (13), and secondary mycotic infection (11). ERU was the second and third most prevalent disease in autopsies and enucleations, respectively. This condition was commonly associated with glaucoma (15). Glaucoma (25) and cataract (20) were the most prevalent secondary alterations in the evaluated cases. Keratitis (20) and corneal rupture (16) were among the most prevalent consequences of trauma. Information presented herein may guide clinicians and pathologists, contributing to the early diagnosis of potentially vision-impairing conditions and raising the chances of successful treatment and cure.
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Affiliation(s)
- Mariana M Flores
- Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA (Flores, Del Piero, Langohr).,Large Animal Pathology Service, New Bolton Center, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA (Habecker).,Current address: Departamento de Patologia, Laboratório de Patologia Veterinária, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil (Flores)
| | - Fabio Del Piero
- Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA (Flores, Del Piero, Langohr).,Large Animal Pathology Service, New Bolton Center, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA (Habecker).,Current address: Departamento de Patologia, Laboratório de Patologia Veterinária, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil (Flores)
| | - Perry L Habecker
- Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA (Flores, Del Piero, Langohr).,Large Animal Pathology Service, New Bolton Center, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA (Habecker).,Current address: Departamento de Patologia, Laboratório de Patologia Veterinária, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil (Flores)
| | - Ingeborg M Langohr
- Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA (Flores, Del Piero, Langohr).,Large Animal Pathology Service, New Bolton Center, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA (Habecker).,Current address: Departamento de Patologia, Laboratório de Patologia Veterinária, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil (Flores)
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Slenter IJM, Hermans H, Ensink JM, Willems DS, Veraa S, Grinwis GCM, Boevé MH. Clinical, ultrasonographic, and histopathologic findings in seven horses with Descemet's membrane detachment: A case series. Vet Ophthalmol 2019; 23:181-189. [PMID: 31544302 PMCID: PMC7003845 DOI: 10.1111/vop.12710] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2018] [Revised: 08/16/2019] [Accepted: 08/23/2019] [Indexed: 02/06/2023]
Abstract
OBJECTIVE To describe ultrasonography as a diagnostic method of in vivo Descemet's membrane detachment (DMD) in horses. ANIMALS STUDIED Seven horses (three Icelandic horses, two Dutch Warmblood horses, one Appaloosa, and one Welsh Pony), presenting with moderate-to-severe focal or diffuse corneal edema, in whom DMD was suspected on ultrasonographic examination and confirmed with histopathology, were studied. PROCEDURE A retrospective analysis of case records of horses with suspected DMD was performed. RESULTS Median age at presentation was 14 years (range 11-24). Clinical signs in eyes with DMD were unilateral in all horses and included blepharospasm and epiphora (6/7), buphthalmos (5/7), moderate-to-severe focal or diffuse corneal edema (7/7), corneal epithelial bullae (4/7), corneal neovascularization (4/7), Haab's striae (2/7), corneal endothelial precipitates (1/7), fibrin in the anterior chamber (1/7), focal cataract (2/7), and pigment deposits on the anterior lens capsule (1/7). During transpalpebral ultrasonography, a distinct linear echogenic structure was noted in the anterior chamber, initially diverging from, and later running parallel to, the posterior lining of the cornea in all eyes studied. In all cases, the cornea was severely thickened and echogenic, consistent with edema, and DMD was suspected. In all horses, the clinical signs progressed and the affected eye was eventually enucleated. Histopathology revealed DMD (7/7), spindle cell proliferation (4/7), Descemet's membrane reformation (3/7), and inflammation of the anterior uvea (5/7). Overall incidence was 1.04%. CONCLUSIONS Ultrasonography is an adequate tool in diagnosing DMD in horses. Descemet's membrane detachment should be included in the differential diagnosis in horses with dense focal or diffuse corneal edema.
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Affiliation(s)
- Inge J M Slenter
- Faculty of Veterinary Medicine, Department of Clinical Sciences of Companion Animals, Ophthalmology Section, Utrecht University, Utrecht, The Netherlands
| | - Hanneke Hermans
- Faculty of Veterinary Medicine, Department of Equine Sciences, Surgery Section, Utrecht University, Utrecht, The Netherlands
| | - Jos M Ensink
- Faculty of Veterinary Medicine, Department of Equine Sciences, Surgery Section, Utrecht University, Utrecht, The Netherlands
| | - Dorien S Willems
- Faculty of Veterinary Medicine Department of Clinical Sciences of Companion Animals, Diagnostic Imaging, Utrecht University, Utrecht, The Netherlands
| | - Stefanie Veraa
- Faculty of Veterinary Medicine Department of Clinical Sciences of Companion Animals, Diagnostic Imaging, Utrecht University, Utrecht, The Netherlands
| | - Guy C M Grinwis
- Faculty of Veterinary Medicine, Department of Pathobiology, Utrecht University, Utrecht, The Netherlands
| | - Michael H Boevé
- Faculty of Veterinary Medicine, Department of Clinical Sciences of Companion Animals, Ophthalmology Section, Utrecht University, Utrecht, The Netherlands
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