Ophthalmology in horses encompasses the study and treatment of eye disorders and diseases affecting equine species. Equine ophthalmic conditions can range from conjunctivitis and corneal ulcers to more complex issues such as uveitis and cataracts. These conditions can impact a horse's vision and overall well-being. Diagnostic techniques in equine ophthalmology include visual examinations, fluorescein staining, and advanced imaging methods like ultrasonography. Treatment approaches vary depending on the specific condition and may involve medication, surgical intervention, or supportive care. This page compiles peer-reviewed research studies and scholarly articles that explore the anatomy, pathology, diagnostics, and treatment modalities related to equine ophthalmology.
Vanderstraeten E, Bogaert L, Bravo IG, Martens A.Squamous cell carcinoma (SCC) represents the most common malignant tumour of the eye and external genitals in horses. Comparable to humans, papillomaviruses (PV) have been proposed as etiological agents of cancer in horses and recently, Equine papillomavirus type 2 (EcPV2) has been identified in genital SCCs. Hitherto it had never been demonstrated in ocular SCCs. The first goal of this study was to determine the prevalence of EcPV2 DNA in tissue samples from equine genital and ocular SCCs, genital papillomas and penile intraepithelial neoplasia (PIN) lesions, using EcPV2-specific PCR. The sec...
Reinstein SL, Lucio-Forster A, Bowman DD, Eberhard ML, Hoberg EP, Pot SA, Miller PE.A 4-year-old Hanoverian gelding was evaluated because of a mobile worm-like structure in the right eye. Results: Ophthalmologic examination of the right eye revealed a white, thin, coiled, mobile parasite, which was presumed to be a nematode, located in the ventral portion of the anterior chamber of the eye; there also were vitreal strands located temporally and inferiorly near the margin of the pupil. Results of ophthalmologic examination of the left eye were unremarkable. Results: The horse was treated with a neomycin-polymyxin B-dexamethasone ophthalmic solution applied topically (1 drop, q...
Sindak N, Kandemir L, Yertürk M, Biricik HS.To determine physiologic levels of tear production in Arabian (AH) and throughbred horses (TH) by using phenol red thread test (PRT). Methods: The study was performed on 16 AH and 14 TH, ranging from 2.5 to 24 years of age, housed in a stable situated in the Sanliurfa of Turkey. Methods: For the measurement of PRT, the strip was placed under the lower eyelid approximately one-third the distance from the temporal to nasal canthus and left for 15 s. The length of the wet area was measured in mm and compared among breed, sex, and age groups and between eyes of both sides. Results: The mean length...
Finno CJ, Eaton JS, Aleman M, Hollingsworth SR.A 23-year-old female mule was presented for bilateral ocular abnormalities and an abnormal pelvic limb gait. Results: Anisocoria, unilateral enophthalmos, medial strabismus, ptosis, pupillary light reflex deficits, and bilateral reticulated pigmentary retinopathy were observed on ophthalmic examination. Neurologic abnormalities included right-sided facial nerve paralysis, extensive symmetric muscle atrophy, and asymmetric pelvic limb ataxia with an abnormal pelvic limb gait. A positive titer (1:40) for equine protozoal myeloencephalitis (EPM) associated with Neospora hughesi was obtained from ...
McMullen RJ, Davidson MG, Campbell NB, Salmon JH, Gilger BC.To determine appropriate intraocular lens (IOL) implant strength to approximate emmetropia in horses. Methods: 16 enucleated globes and 4 adult horses. Methods: Lens diameter of 10 enucleated globes was measured. Results were used to determine the appropriate-sized IOL implant for insertion in 6 enucleated globes and 4 eyes of adult horses. Streak retinoscopy and ocular ultrasonography were performed before and after insertion of 30-diopter (D) IOL implants (enucleated globes) and insertion of 25-D IOL implants (adult horses). Results: In enucleated globes, mean +/- SD lens diameter was 20.14 ...
Chen T, Ward DA.To determine tear volume, turnover rate, and flow rate in ophthalmologically normal horses by use of fluorophotometry. Methods: 12 mares free of ophthalmic disease. Methods: 2 microL of 10% sodium fluorescein was instilled onto 1 eye of each horse, and tear samples were collected via microcapillary tubes from the inferonasal conjunctival culde-sac at 0, 2, 4, 6, 10, 15, and 20 minutes after instillation. Collected tear samples were then measured for fluorescein concentrations with a computerized scanning ocular fluorophotometer. A decay curve plot of concentration changes over time was used to...
Grinninger P, Skalicky M, Nell B.To assess natural variations in degree of refraction, corneal curvature, corneal astigmatism, corneal radius, and intraocular distance of healthy equine eyes. Methods: 159 horses with healthy eyes that were admitted to a veterinary teaching hospital for nonophthalmic surgeries. Methods: Eyes of horses were examined with a retinoscope prior to anesthesia and with a keratograph and A- and B-scan ultrasonographic biometers during surgery. In addition, manual caliper measurements of horizontal and vertical corneal radii were obtained. Results: Mean +/- SD degree of refraction in the horizontal mer...
Boveland SD, Moore PA, Mysore J, Krunkosky TM, Dietrich UM, Jarrett C, Paige Carmichael K.Determine the effects of matrix metalloproteinases (MMPs)-2, -9, macrophage inflammatory protein-2 (MIP-2), tissue inhibitors of matrix metalloproteinase (TIMP)-1 and -2 by immunohistochemical expression in fungal affected and purulonecrotic corneas. Methods: Paraffin-embedded equine corneal samples; normal (n = 9), fungal affected (FA; n = 26), and purulonecrotic without fungi (PN; n = 41) were evaluated immunohistochemically for MMP-2, -9, MIP-2, TIMP-1 and -2. The number of immunoreactive inflammatory cells was counted and statistics analyzed. Western blot was performed to detect MMP-2, MMP...
Clode AB, Davis JL, Salmon J, LaFevers H, Gilger BC.To determine the degree of ocular penetration and systemic absorption of commercially available topical ophthalmic solutions of 0.3% ciprofloxacin and 0.5% moxifloxacin following repeated topical ocular administration in ophthalmologically normal horses. Methods: 7 healthy adult horses with clinically normal eyes as evaluated prior to each treatment. Methods: 6 horses were used for assessment of each antimicrobial, and 1 eye of each horse was treated with topically administered 0.3% ciprofloxacin or 0.5% moxifloxacin (n = 6 eyes/drug) every 4 hours for 7 doses. Anterior chamber paracentesis wa...
Wotman KL, Utter ME.To assess the effect of treatment with a topical ophthalmic preparation of 1.2% nalbuphine solution on corneal sensitivity in clinically normal horses. Methods: 8 horses. Methods: Baseline corneal touch threshold (CTT) was measured (defined as the mean filament length [mm] at which a consistent blink response was elicited) for both eyes of each horse by use of a Cochet-Bonnet aesthesiometer. Subsequently, 0.2 mL of 1.2% nalbuphine solution was instilled in 1 randomly selected eye of each horse, and 0.2 mL of artificial tears solution was instilled in the contralateral eye (control treatment). ...
Leiva M, Peña T, Armengou L, Cesarini C, Monreal L.Septicemia in humans is described as a leading cause of uveitis, which eventually can induce blindness. Objective: Uveal inflammatory findings could be related to sepsis severity in newborn foals and might be used as an indirect indicator for survival. Methods: Seventy-four septic foals, 54 nonseptic foals, and 42 healthy foals. Methods: Prospective observational clinical study. A detailed blinded, ophthalmic examination was performed by boarded ophthalmologists on all admitted newborn foals. Foals were grouped as septic (when blood culture resulted positive or the sepsis score was > or =14...
Payne RJ, Lean MS, Greet TR.Between October 2000 and January 2007, 24 horses were presented with suspected squamous cell carcinoma (SCC) of the third eyelid. The hospital's medical records were analysed retrospectively to gain data about the cases, and telephone follow-up was obtained from the owners and referring veterinary surgeons. The resected third eyelid was submitted for histological examination in 21 cases; in the other three cases the tissue was not submitted at the owners' request, for economic reasons. SCC was confirmed in 16 of these 21 cases, three cases were diagnosed histologically as lymphoid hyperplasia,...
Matthews A, Gilger BC.Equine immune mediated keratopathies are common in both Europe and the USA. This review article will compare the clinical differences in horses with this disease and also review the current theories on pathogenesis and treatment of equine IMMK.
Plummer CE, Ollivier F, Kallberg M, Brooks D, Barrie K, Utter M, Gelatt K.Amniotic membrane transplantation (AMT) is an effective clinical therapy for reconstruction of the ocular surface in human and veterinary patients. Amnion is avascular and strong, contains antiangiogenic and antiinflammatory properties and growth factors, and has properties that prevent or decrease fibrosis in healing tissue. Indications for its use are steadily growing and include grafting to replace diseased, missing or excised tissue, patching to support diseased tissue during the healing process and as a substrate for the expansion of epithelial cells for transplantation to the cornea. AMT...
Ledbetter EC, Scarlett JM.To describe morphologic features, pachymetry and endothelial cell density of the normal equine cornea and limbus by in vivo confocal microscopy. Methods: Ten horses without ocular disease. Methods: The central and peripheral corneas were examined with a modified Heidelberg Retina Tomograph II and Rostock Cornea Module using a combination of automated and manual image acquisition modes. Thickness measurements of various corneal layers were performed and endothelial cell density determined. Results: Images of the constituent cellular and noncellular elements of the corneal epithelium, stroma, en...
Selk Ghaffari M, Sabzevari A, Radmehr B.To observe the effect of topical 1% tropicamide on equine tear production as measured by Schirmer I tear test. Methods: Fourteen adult horses received one drop of 1% tropicamide ophthalmic solution in one eye and the opposite eye served as the control. The tear production in both eyes was tested at 1, 2, 4, 6, and 24 h after 1% tropicamide administration. Results: Measurements made 1 h after treatment revealed a significant reduction in Schirmer tear test values in tropicamide treated eyes (P = 0.002). The observed decrease in tear production was maintained up to 4 h after treatment (P = 0.002...
Gilger BC, Brooks DE.This first IEOC symposium met its goals of gathering a group of leading equine ophthalmology clinicians and researchers to identify the challenges of the field. To facilitate collaboration, notes from round-table discussions, including the ideas and plans that were discussed are being complied and will be distributed to the attendees. Development of an IEOC membership organisation and website was discussed and supported by the group in an effort further to advance the science of equine ophthalmology. To present results from the collaborations made at this first IEOC meeting, an IEOC mini-sympo...
Brooks DE, Taylor DP, Plummer CE, Quinn R, Kallberg ME, Sheppard B, Barrie KP, Blackwood SE, Nunnery CM, Ben-Shlomo G, Clark CJ, Woodworth AA.To describe clinical and histologic findings in horses with iris abscesses. Design Retrospective medical records study. Methods: Medical records of horses that had iris abscesses at the University of Florida Veterinary Medical Center, Peterson & Smith Equine Hospital, and Veterinary Eye Specialists of London, Ontario, from 2005 to 2008 were reviewed. Methods: Data collected from the medical records included signalment, clinical and histologic descriptions of ocular lesions, therapy, complications, and visual outcomes. Results: The medical records of two Quarterhorses, one pony, one warmblood, ...
Baumgartner WA, Storey ES, Paulsen DB.Intraocular choristomas are rare anomalies in domestic animals and are often associated with multiple ocular malformations. A Thoroughbred foal presented for ocular abnormalities and was diagnosed with microphthalmia, corneal dermoids, severe anterior segment dysgenesis (including glandular choristomas), aphakia, retinal dysplasia, and optic nerve hypoplasia. Morphological, histochemical, and immunohistochemical comparisons were made between ocular choristomatous tissues from this foal and lacrimal gland, third eyelid gland, nasopharynx, trachea, and lacrimal sac/nasolacrimal duct from normal ...
Bertolucci C, Giudice E, Fazio F, Piccione G.The present study was undertaken to investigate the existence of intraocular pressure (IOP) rhythms in athletic thoroughbred horses maintained under a 24 h cycle of light and darkness (LD) or under constant light (LL) or constant dark (DD) conditions. We identified an IOP circadian rhythm that is entrained to the 24 h LD cycle. IOP was low during the dark phase and high during the light phase, with a peak at the end of the light phase (ZT10). The circadian rhythm of IOP persisted in DD (with a peak at CT9.5), demonstrating an endogenous component in IOP rhythm. As previously shown in other mam...
Brooks DE.Corneal transplantation, amniotic membrane transplantation, phacoemulsification cataract extraction, and laser glaucoma therapy are routine ophthalmic surgical procedures in horses. This article discusses the indications, techniques, and postoperative complications of these and other ophthalmic surgical procedures in horses. Meticulous and accurate anatomic repair can minimize postoperative complications to maintain positive visual outcomes in ophthalmic surgery of the horse.
Andersson LS, Juras R, Ramsey DT, Eason-Butler J, Ewart S, Cothran G, Lindgren G.Equine Multiple Congenital Ocular Anomalies (MCOA) syndrome consists of a diverse set of abnormalities predominantly localized to the frontal part of the eye. The disease is in agreement with a codominant mode of inheritance in our horse material. Animals presumed to be heterozygous for the mutant allele have cysts originating from the temporal ciliary body, peripheral retina and/or iris. In contrast, animals predicted to be homozygous for the disease-causing allele possess a wide range of multiple abnormalities, including iridociliary and/or peripheral retinal cysts, iridocorneal angle abnorm...
Yi NY, Davis JL, Salmon JH, Gilger BC.To determine ocular distribution and toxicity of a single injection of intravitreal triamcinolone acetonide (TA) in normal horses. Methods: Six adult horses, donated to North Carolina State University. Methods: Six horses were injected intravitreally with either 10, 20, or 40 mg (n = 2 each) of TA. The opposite eye of each horse was injected with balanced salt solution (BSS). Ocular toxicity was assessed by biomicroscopy, tonometry, indirect ophthalmoscopy, and electroretinogram. Aqueous humor (AH), vitreous humor (VH), and plasma samples were collected. Horses were euthanized 7 or 21 days aft...
Barnett KC, Blunden AS, Dyson SJ, Whitwell KE, Carson D, Murray R.The case histories described each presented with a visual deficit, varying from permanent total blindness with ophthalmoscopic evidence of optic atrophy to variable and transient visual disturbances, including occasional blindness, but with absence of ophthalmoscopic or any other ocular abnormality. Methods: Three horses of widely different age and type, but all with an original history of upper respiratory tract infection. Methods: All three cases were examined by a specialist veterinary ophthalmologist. In addition, magnetic resonance imaging (MRI) and, where possible, postmortem and histopa...
Giuliano EA, MacDonald I, McCaw DL, Dougherty TJ, Klauss G, Ota J, Pearce JW, Johnson PJ.Local photodynamic therapy (PDT) is a novel cancer therapy in veterinary ophthalmology. A prospective pilot study seeking to demonstrate proof of principle and safety for the treatment of equine periocular squamous cell carcinoma (PSCC) was therefore conducted. We hypothesized that surgical excision with adjunctive local PDT is an effective and safe treatment for equine PSCC. Methods: Nine horses (10 eyes) with PSCC were treated with surgical resection, local infiltration of resulting wound beds with 2-[1-hexyloxyethyl]-2-devinylpyropheophorbide-a (HPPH) and irradiation with 665-nm wavelength ...
Matthews AG.This paper overviews some recent developments in mammalian corneal immunobiology, and discusses how these may act as pointers towards understanding the immunology underlying some common corneal diseases in the horse, including infectious ulceration and presumptively immune-mediated non-ulcerative disease. Specifically, three aspects of corneal immunobiology are examined: the role of Toll-like receptors in surface immunity and in the etiogenesis of microbial ulceration, the relationship between conjunctiva associated lymphoid tissue (CALT) and immunoprotection of the corneal surface, and the me...
McMullen RJ, Clode AB, Pandiri AK, Malarkey DE, Michau TM, Gilger BC.A case of epibulbar melanoma in a 6-month-old, gelded, chestnut Hanoverian foal is reported. The location and clinical appearance upon initial presentation led to the tentative diagnosis of staphyloma or a congenital mass of unknown origin. An attempt was made to surgically excise the mass under general anesthesia, but due to its infiltrative nature and intraoperative appearance, most, but not all was removed without compromising the integrity of the globe. Histopathological evaluation revealed a multinodular to packeted, poorly demarcated, unencapsulated, infiltrative exophytic melanocytic ne...
Pinto NI, Gilger BC.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 wer...
Ström L, Bröjer J, Ekesten B.Visual evoked potentials (VEPs) are electrical potentials generated by neurons in the central nervous system in response to visual stimuli. A series of positive and negative wavelets in response to flash-stimuli (flash-VEP; FVEP) or reversing, iso-luminant patterns (pattern-VEP; PVEP) are recorded. Pathological conditions affecting the post-retinal pathways can alter overall waveform morphology, and also affect wavelet peak times and amplitudes. FVEPs have recently been described in horses, but more data on the variability within and between subjects is required, to adequately interpret result...
Rushton JO, Tichy A, Nell B.To date assessment of changes in ocular temperature, as a hallmark of uveitis in horses has not been determined. Therefore the aim of the current study was to determine whether ocular temperature is increased in acute uveitic eyes compared with non-uveitic eyes, and to compare an affordable thermometry device with a thermography device. Methods: Ocular temperatures of both eyes of five horses with acute unilateral uveitis and 10 normal horses were measured using thermometry and thermography. Presence and absence of acute uveitis were diagnosed through a complete ophthalmological examination. A...
Whigham HM, Brooks DE, Andrew SE, Gelatt KN, Strubbe DT, Biros DJ.Contact neodymium:yttrium aluminum garnet (Nd:YAG) laser transscleral cyclophotocoagulation (TSCP) was performed on 23 eyes of 16 horses for treatment of glaucoma. The mean highest preoperative IOP was 51 +/- 17 mmHg. Follow-up evaluation was available for 19 eyes 1 day after surgery, 14 eyes from 1 to 2 weeks, 16 eyes from 4 to 6 weeks, 9 eyes from 12 to 16 weeks, and 10 eyes greater than 20 weeks after laser treatment. The mean intraocular pressure (IOP) the day following surgery was 34 +/- 13 mmHg. The mean IOP for each follow-up period was: one to two weeks postoperative, 23 +/- 9 mmHg; fo...
Leiva M, Peña T, Armengou L, Cesarini C, Monreal L.Septicemia in humans is described as a leading cause of uveitis, which eventually can induce blindness. Objective: Uveal inflammatory findings could be related to sepsis severity in newborn foals and might be used as an indirect indicator for survival. Methods: Seventy-four septic foals, 54 nonseptic foals, and 42 healthy foals. Methods: Prospective observational clinical study. A detailed blinded, ophthalmic examination was performed by boarded ophthalmologists on all admitted newborn foals. Foals were grouped as septic (when blood culture resulted positive or the sepsis score was > or =14...
Hermans H, Ensink JM.Distichiasis is very uncommon in horses and treatment options and outcome remain unknown. Objective: To describe treatment and long-term follow-up of distichiasis in the horse. Methods: Retrospective clinical study. Methods: Case records of horses admitted for diagnosis and treatment of uni- or bilateral distichiasis between 2003 and 2012 were reviewed. Long-term (>6 months after last treatment) follow-up was by telephone conversation with the owner or referring veterinarian. Data were analysed using a Chi-squared test. Results: Eighteen cases were identified, of which 17 were Friesians. All h...
Pirie CG, LoPinto AJ, Tenney WA.OBJECTIVE To assess and compare 2 injection techniques for conducting ocular anterior segment indocyanine green angiography (ASICGA) and sodium fluorescein (SF) angiography in horses. ANIMALS 3 healthy adult female horses (age range, 19 to 25 years). PROCEDURES Horses were sedated, jugular catheters were placed, and manual restraint was used to ensure proper positioning for the angiography procedure. Two injection techniques (IV and intra-arterial) were performed for each horse 1 week apart. Intravenous injections of 0.25% indocyanine green (ICG; 50 mg) and 10% SF (10 mg/kg) were administered ...
Brooks DE.Corneal transplantation, amniotic membrane transplantation, phacoemulsification cataract extraction, and laser glaucoma therapy are routine ophthalmic surgical procedures in horses. This article discusses the indications, techniques, and postoperative complications of these and other ophthalmic surgical procedures in horses. Meticulous and accurate anatomic repair can minimize postoperative complications to maintain positive visual outcomes in ophthalmic surgery of the horse.
Regnier A, Berton I, Concordet D, Douet JY.To assess the degree and duration of corneal anaesthesia provided by topical application of a non-ophthalmic 2% lidocaine gel in horses. Methods: Experimental, 'blinded', randomized prospective study. Methods: Twelve adult horses without relevant ocular abnormalities. Methods: Baseline corneal touch threshold (CTT) measurements were obtained bilaterally by use of a Cochet-Bonnet aesthesiometer just prior to topical treatment. A volume of 0.2mL of 2% lidocaine gel was administered in one randomly selected eye and the same volume of a viscous lubricant in the other eye to serve as control. The C...
Allbaugh RA, Keil SM, Ou Z, Bello NM.To assess intraocular pressure (IOP) in conditioned equine athletes and document changes with exercise. A secondary objective was to assess associations between IOP and heart rate, as well as with other subjective physical parameters. Methods: Horses were evaluated during 50 mile endurance ride competitions. Data were collected on 69 horses during five different competitions at three different locations with 59 horses ridden once, nine horses ridden in two competitions, and one horse ridden in three competitions for a total of 80 horse-ride combinations. Methods: Intraocular pressure was measu...
Rushton JO, Kolodziejek J, Tichy A, Nowotny N, Nell B.To date the influence of herpesviruses on the development of equine ocular diseases has not been clearly determined. Objective: The purpose of this study was to illustrate the course of equine ocular findings over a period of 18 months at 6 month intervals, in correlation with the results of herpesvirus detection. Methods: 266 Lipizzaners in 3 federal states of Austria underwent complete ophthalmologic examination 4 times. Blood samples, nasal- and conjunctival swabs were obtained at the same time and used for the detection of the equid gammaherpesviruses EHV-2 and EHV-5 using consensus herpes...
Hidaka S, Kobayashi M, Ando K, Fujii Y.Lomefloxacin is a broad-spectrum fluoroquinolone antibiotic used for the treatment of bacterial extraocular disease. This study investigated the efficacy and safety of lomefloxacin eye drops for bacterial extraocular disease in horses. Lomefloxacin ophthalmic solution (0.3%) was instilled three times daily for 2-5 days in 65 horses diagnosed with bacterial extraocular disease based on clinical findings. Clinical observations and bacteriological examinations were performed at the start of treatment, 2 and 5 days after the start of treatment, and at the discontinuation or termination of treatmen...
Schaer BD.The emergency clinician is frequently in the position of receiving, evaluating, and initiating treatment on horses with ophthalmic emergencies or orbital trauma. In the best of circumstances, an ophthalmologist is available to guide initial therapy and ultimately assume responsibility for the management of the patient during the remainder of its hospitalization, but this is not always the case. The information presented here is meant to provide the emergency clinician with basic guidelines for the initial assessment and management of horses sustaining ocular injuries or presented with an ophth...
Charnock LN, Keys DA, McMullen RJ.Identify ocular findings associated with blunt ocular trauma to aid in differentiation from other equine ocular diseases. Methods: Retrospective case-control study. Methods: Medical records of horses at the Equine Clinic Munich-Riem, Munich, Germany and Auburn University, College of Veterinary Medicine were reviewed. Age, sex, breed, laterality, and clinical findings on ophthalmic examination, as well as an observed (confirmed) or unobserved (suspected) history of trauma, were recorded. Statistical analysis was performed to identify any correlation between clinical signs and blunt ocular traum...
Hardman C, McIlnay TR, Dugan SJ.A 3-year-old Paint gelding was presented for sudden onset of cataract affecting the right eye. Ophthalmic examination revealed subtle to mild microphthalmia and a mature cataract affecting the right globe. The right eye was treated with an antibiotic-corticosteroid ophthalmic ointment and phacofragmentation was recommended. On re-examination 5 months later, resorption of the cortex of the right lens and a morgagnian cataract were evident. The nucleus was positioned ventronasally in the lens capsule. The right eye had light perception, and a menace response was present. Examination of the right...
Rodriguez Galarza RM, McMullen RJ.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. Methods: Ten adult horses of various breeds with DMD or DMRS. Methods: 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 =Â...
Lassaline-Utter M, Gemensky-Metzler AJ, Scherrer NM, Stoppini R, Latimer CA, MacLaren NE, Myrna KE.To describe the clinical presentation, treatment, and outcome of a corneal dystrophy in Friesian horses and to analyze affected horses' pedigrees to investigate its heritability. Methods: Nine Friesians with bilateral disease were identified. Methods: Retrospective medical record review was used to identify Friesian horses exhibiting bilateral symmetric corneal lesions. Variables identified from medical records included patient sex and age at diagnosis; location, depth and size of corneal lesions; medical and surgical therapy instituted; and visual outcome. A four-generation pedigree for each ...
Blanchard A, Barr EM, Gilger BC.The purpose of this case series is to evaluate the use of spectral domain optical coherence tomography (SD-OCT) imaging in equine corneal disease to demonstrate the feasibility, diagnostic effectiveness, and limitations of this imaging modality. Methods: Retrospective study: Handheld SD-OCT (Envisu, Bioptigen Inc, Morrisville, NC) was used for high-resolution imaging of horses with corneal disease presenting to the North Carolina State University Equine Ophthalmology Service from 2013 to 2018. Results: Fourteen horses were included in this study, including six horses with corneal ulceration, t...
Andrysikova R, Pot S, Rüegg S, Markova J, Horackova E, Kolos F, Voelter K, Spiess B.To screen a closed herd of the Old Kladruber Horses (OKH) for the prevalence of ocular disorders and report normal ocular variations. Methods: Two hundred and sixty-one horses, 122 Old Kladruber Gray Horses, and 139 Old Kladruber Black Horses owned by the National Stud Farm Kladruby nad Labem, Czech Republic, were included in the study with signalment and pedigree information recorded. Methods: Bilateral ocular examination of manually restrained horses was performed in a darkened environment by a single examiner (RA), using a portable slit-lamp biomicroscope, direct ophthalmoscope, and monocul...
Sweeney CR, Russell GE.To determine type and frequency of complications associated with use of a one-hole subpalpebral lavage (SPL) system in horses. Methods: Retrospective study. Methods: 150 horses with 156 SPL systems. Methods: Signalment, primary complaint, method used for placement, time SPL system was in place, and complications were retrieved from medical records. Results: Complications were not associated with placement, maintenance, or removal of 66 of 156 (42%) SPL systems. A minor complication was reported in association with 53 (34%) SPL systems, and a serious complication was reported in association wit...
Henriksen ML, Dwyer AE, Krarup Nielsen R, Bäcklund S, Dahlmann Christensen N, Holberg Pihl T.To describe the most common ocular abnormalities in the Icelandic horse with focus on equine recurrent uveitis (ERU) and association between ocular abnormalities and summer eczema and coat colors. Methods: A descriptive cross-sectional study. A complete physical and ophthalmic examination as well as measurement of serum titers for Leptospira serovariants was performed on Icelandic horses from Denmark (DK) and the United States (USA). Results: One hundred and twelve Icelandic horses living in DK and 26 Icelandic horses living in the United States were included in this study (total of 138 horse...
Beard WL, Wilkie DA.Ocular and periorbital sarcoids and squamous cell carcinoma are common in equine practice. Extensive involvement of periorbital tissues often necessitates removal of the globe if the function of the eyelids can not be maintained with tumor removal alone. This report describes a modification of the standard enucleation or exenteration technique for cases in which there is insufficient skin to achieve primary closure following complete surgical excision. The caudal portion of the dorsal orbital rim is protuberant; partial excision with an osteotome facilitates skin closure by decreasing the size...
Cooley PL.When compared with small domestic animals, the horse has unique ocular characteristics (complete bony orbit, well-developed eyelid muscles, a nasal and temporal gray limbal line, granulae iridica, paurangiotic fundus). Knowledge of normal equine ocular anatomy is essential for ocular lesion interpretation. It is important to obtain a full history and general examination before sedation, nerve blocks, or other diagnostic ophthalmic tests are performed. All ocular examinations should include a systematic evaluation of both the anterior and posterior segments. Selection of other diagnostic tests ...
Tofflemire KL, Whitley EM, Flinn AM, Dufour VL, Ben-Shlomo G, Allbaugh RA, Griggs AN, Peterson CS, Whitley DR.To compare the effect of commercially available solution and compounded ointment formulations of dorzolamide(2%)-timolol(0.5%) on intraocular pressure (IOP) of normal horses. Methods: Eighteen clinically normal horses. Methods: A randomized, masked prospective design was used with horses divided into two equal groups. One eye of each horse was selected for topical ophthalmic treatment with either 0.2 mL of dorzolamide(2%)-timolol(0.5%) solution or 0.2 g of dorzolamide(2%)-timolol(0.5%) ointment every 12 h for 5 days. The contralateral eye of horses in both groups was untreated. Rebound tonomet...
Best LJ, Hendrix DV, Ward DA.To evaluate the tear film osmolality and electrolyte composition in healthy horses. Methods: 15 healthy adult horses. Methods: Each horse was manually restrained, and an ophthalmic examination, which included slit-lamp biomicroscopy, indirect ophthalmoscopy, and a Schirmer tear test, was performed. Tear samples were collected from both eyes with microcapillary tubes 3 times at 5-minute intervals. The tear samples for each horse were pooled, and the osmolality and electrolyte concentrations were measured. The mean (SD) was calculated for each variable to establish preliminary guidelines for tea...
Allbaugh RA, Ben-Shlomo G, Whitley RD.To evaluate the impact of extensive bullet-hole nontapetal fundic lesions in horses on retinal function as measured by full-field electroretinography (ERG). Methods: Full-field ERG was performed on two horses with numerous bullet-hole lesions in the nontapetal fundus of both eyes. The ERG was first recorded from the eye with the more extensive lesions in response to a low-intensity light stimulus (0.03 cd s/m(2) ) that was given at times (T) T = 5, 10, 15, 20 min of dark adaptation. Consecutively, combined rod-cone response was evaluated bilaterally in response to high-intensity light stimulus...
Peyrecave-Capo X, Saulnier N, Maddens S, Gremillet B, Desjardins I.Human autologous serum (AS) and umbilical cord serum (UCS) both contain growth and neurotrophic factors that promote corneal healing. Unassigned: Our objectives were to compare equine AS and UCS cytokine and growth factor profiles and to assess the safety and clinical feasibility of the therapeutic use of UCS eye drops in cases of spontaneous complex ulcers. Unassigned: Prospective clinical trial. Unassigned: Vitamin A insulin growth factor, platelet-derived growth factor-BB, transforming growth factor (TGF)-β1 (enzyme-linked immunosorbent assay), interleukin (IL)-1β, IL-6, interferon-γ, an...
Valentini S, Castagnetti C, Musella V, Spinella G.Objective of this study was to describe intraocular measurements in newly born foals (1-7 days of age) and assess the association between globe measurements and gender, laterality, and body weight. B-scan ultrasonographic biometry was performed on both eyes of 22 healthy foals (44 eyes) ages 1-7 days using a 10-MHz transducer. Intraocular measurements (anterior chamber depth, central lens thickness, vitreous chamber depth, axial globe length, longitudinal globe length, lens poles distance) were carried out using the ultrasound internal calipers. The influence of gender (male or female), latera...
Hamor RE, Whelan NC.Corneal ulcers are one of the most common ocular disease presentations in the horse. With the use of correct diagnostic techniques and selection of an appropriate treatment regimen, most cases result in a satisfactory outcome. The eye does not respond well to inflammation, and in complicated ulcers, this should be managed aggressively using systemic NSAIDs with a high priority assigned to removing the infectious agent. Care needs to be taken to avoid topical or systemic corticosteroid use for the treatment of equine ocular disease, however, unless the clinician is completely sure that the corn...
Keenan AV, Townsend WM.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 c...
