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.
Knickelbein KE.Numerous ocular diseases cause visual impairment and induce ocular pain that may be associated with undesired behaviors in horses. Horses with ocular pain, indicated by the presence of blepharospasm, blepharoedema, ocular discharge or rubbing the eye, should be rested from work to avoid worsening the ocular disease and to avoid undesired behaviors associated with pain or vision impairment. Horses with ocular disease are frequently head shy. Some stoic horses may not have obvious outward clinical signs despite significant visual impairment, and as such, undesired behaviors such as spooking, bal...
So YM, Kwok WH, Yap C, Wong COL, Smalley SGR, Forbes BS, Chow DWY, Ho ENM.This paper describes the detection and longitudinal monitoring of cyclosporine in plasma and urine after subconjunctival implant administration in a horse. Sensitive liquid chromatography tandem mass spectroscopy (LC-MS/MS) methods for detecting cyclosporine in horse plasma and urine have been developed and validated, with estimated limits of detection down to 1 pg/mL in both matrices. The developed methods enabled longitudinal monitoring of cyclosporine levels in blood and urine samples collected over 6 months from a horse that had received an ocular cyclosporine implant.
Dagenais A, Juette T, Benoit-Biancamano MO, Vanore M.(1) Context: Squamous cell carcinoma (SCC) is the most prevalent ocular neoplasm in horses, with a reported 45% recurrence rate when managed by surgery alone. (2) Objective: To evaluate the effect of adjunctive cisplatin biodegradable beads (CBBs) on recurrence rates of equine corneolimbal squamous cell carcinoma (SCC) and to document associated adverse effects. (3) Methods: Seventeen cases of histopathologically confirmed corneolimbal SCC in horses were retrospectively identified. Masses were surgically excised by keratectomy and/or conjunctivectomy under general anesthesia, followed by impla...
Bourassi S, Jack H, Florczyk A.A 4-year-old Arabian cross paint mare was referred for evaluation of chronic mucopurulent discharge and epiphora of the left eye. Ophthalmic and radiographic evaluations confirmed distal nasolacrimal duct atresia with absence of the nasolacrimal orifice. Initial minimally invasive treatments, including guidewire-assisted catheterization and diode laser photoablation, were unsuccessful. Definitive treatment was achieved using a Fogarty arterial embolectomy catheter under standing sedation. Controlled balloon inflation and deflation enabled progressive dilation of the obstructed duct, and a surg...
Graham AE, Carslake HB, Malalana F.Evidence for optimal location of subpalpebral lavage (SPL) systems is lacking. Objective: To compare the rate and types of complications with SPL systems located in central upper- compared with medial lower-eyelid in hospitalised patients. Methods: Prospective, randomised treatment trial. Methods: Horses admitted for ophthalmic treatment using an SPL system from February 2015 to January 2024 were included if ocular pathology did not necessitate SPL system placement in a specific location. Coin toss was used to determine location. SPL systems were monitored at least daily, and complications wer...
Collins E, Barr E, Zhang C, Steadman M, Gilger B, Henriksen ML.To describe the most efficient topical horizontally centrifuged platelet-rich fibrin (H-PRF) treatment protocol for equine ulcerative keratitis (EUK) that is easy to use, and to report the preliminary concentration of growth factors and cytokines in equine H-PRF. Unassigned: 5 client-owned horses diagnosed with EUK were enrolled over an 11-month period. Unassigned: 3 horses were geldings, and 2 were mares. The mean (± SD) age was 5.95 ± 5.01 years. The owners' main goal was to avoid surgery for EUK. Unassigned: H-PRF was used in 3 different protocols: solid H-PRF, sutured to the EUK area (n ...
Bazzano M, Laus F, Cerquetella M, Spaterna A, Marchegiani A.Phytocannabinoids have the potential to lower intraocular pressure in both normal and glaucomatous eyes and they have been tested in different animal species, but not in the horse. The present paper describes the tonometric curve of healthy adult Italian Saddle horses after oral administration of cannabidiol oil (CBD). Methods: CBD 20% was administered orally (oily solution) at the dose of 1 mg/kg to 8 adult horses and intraocular pressure (IOP) was evaluated by tonometric curve. Data were then compared to those of the same horses obtained the day before (blank) CBD administration. Results: ...
Bandera L, Guerri G, Straticò P, Pincelli MC, Celani G, Varasano V, Vignoli M, Petrizzi L.Although lens diseases are uncommon in horses, they can be disabling in advanced stages. The B-mode ultrasound is useful for diagnosing and monitoring the progression of ocular diseases such as cataracts. Elastography is an ultrasonographic technique that allows the detection and measurement of tissue stiffness. This observational cohort prospective study aimed to determine the feasibility, reproducibility, and repeatability of 2D-shear wave elastography (2D-SWE) of lenses in horses. Forty-six eyes of 23 horses with no evidence of ocular disease were included in this study. The horses underwen...
Lam KP, Keys DA, McMullen RJ.To describe infracyanine green-based photodynamic therapy (InfraCG-PDT) and evaluate outcomes in horses with immune-mediated keratitis (IMMK). Methods: Medical records from 2014 to 2020 from the Equine Clinic Munich-Riem, Germany, and Auburn University Equine Ophthalmology Service identified horses diagnosed with IMMK following ophthalmic examination that had undergone InfraCG-PDT. Methods: Multiple intrastromal injections of EmunDo (InfraCG, A.R.C. Laser, Nuernberg, Germany) within an affected quadrant or the entire cornea were treated with diffuse diode laser energy (FOX A.R.C., Laser, Nuern...
Hefner EM, Stoppini R, McMullen RJ. This study is aimed at describing two unique case presentations of iris hypoplasia and the use of semiconductor diode laser for treatment in the horse. One 20-year-old American Quarter Horse gelding and one 11-year-old pony mare were studied. The presenting clinical signs, surgical technique, and postoperative results for two cases of iris hypoplasia treated with diode laser are described. Immediate postoperative complications-postoperative ocular hypertension (POH), corneal edema, and epithelial bullae-were possible anticipated effects but were controlled with topical medications in the fi...
Ing ST, Pinard CL, James-Jenks EM, Leis ML.Our objective was to investigate the demographics and prevalence of ocular disease in a large referral population of horses in Ontario over a 10-year period. Unassigned: A retrospective analysis of medical records for 283 horses evaluated by Board-certified veterinary ophthalmologists at the Ontario Veterinary College (Guelph, Ontario) was conducted. Signalment and ocular disease were recorded. Unassigned: The 3 most common ocular abnormalities identified were uveitis (43.7%, 123 horses), ulcerative keratitis (42.0%, 119 horses), and cataract (25.1%, 71 horses). Uveitis was most often secondar...
Morgan J, Curtis Shaw G, Weisman J, Cecere T, Carvallo-Chaigneau FR.A 2-d-old Warmblood colt was submitted for autopsy with a spectrum of bilateral ocular abnormalities. At postmortem examination, a constellation of lesions within the anterior segment included retention of ectodermal elements, compatible with choristoma. Ocular choristomas can be localized to different intraocular structures and are rare in equids. The morphologic features in our case were suggestive of abnormal corneal differentiation.
Holz N, Suárez J, Hetzel U, Rampazzo A, Stoppini R.A 15-year-old Swiss Warmblood gelding was presented to the ophthalmology service of Zurich University due to severe visual impairment. Ophthalmic and neurologic examinations were performed, raising suspicion of post-retinal blindness. Standing contrast computed tomography (CT) of the head revealed a partially calcified, soft tissue attenuating mass in the sphenopalatine sinus with concurrent compression of the optic nerves and chiasm. Differential diagnosis included neoplasia and granulomatous disease. The horse was euthanized, and the head was subsequently examined by magnetic resonance imagi...
de Moura Alonso J, Apolonio EVP, Teng FS, Perandré PI, Amorim RL, Mazaro RD, Watanabe MJ, Alves ALG, Hussni CA.In horses, basal cell neoplasms are uncommon benign tumors with slow growth mostly reported in the skin and eyelid. Malignant presentation is even more uncommon. This report describes a basal cell carcinoma (BCC) in the periocular region of a 10-year-old donkey. The animal presented good body condition and a neoformation in the right eye, noted 3 months prior to hospital admission. At the ophthalmological examination, the mass was identified above and adhered to the cornea, measuring 3.0 × 2.5 × 1.5 cm. Cytology revealed a suspicion of a malignant epithelial neoplasm, characterized ...
Płoneczka-Janeczko K, Armstrong E, Siemieniuch-Tartanus M, Magdziarz M.The aim of the study was to explore and characterise healthy foals' eye microbiomes in the first two months of life. Unassigned: Conjunctival swabs were collected three times, not later than 12 h after delivery and again at the end of the first and the second months of life from six clinically healthy foals of the Polish Konik breed. The average interval between the first and second samplings was 33.3 days and between the second and third was 35.6 days. Next-generation sequencing performed on a MiSeq sequencer in paired-end technology was used to analyse the composition of the conjunctival mic...
Stafford LS, Plummer CE, Smith WC, Gibson DJ, Sharma J, Vicuna V, Diakite S, Larkin J.Recurrent uveitis (RU), an autoimmune disease, is a leading cause of ocular detriment in humans and horses. Equine and human RU share many similarities including spontaneous disease and aberrant cytokine signaling. Reduced levels of SOCS1, a critical regulator of cytokine signaling, is associated with several autoimmune diseases. Topical administration of SOCS1-KIR, a peptide mimic of SOCS1, was previously correlated to reduced ocular pathologies within ERU patients. Unassigned: To further assess the translational potential of a SOCS1 mimetic to treat RU, we assessed peptide-mediated modulatio...
Gerras J, Young K, Roberts D, Waldman G, Salmon JH, Gilger BC.To describe the ocular findings, chronology of disease, and serum leptospiral titers in a group of horses, mules, and donkeys following an outbreak of leptospirosis. Unassigned: Fifty Equidae in central North Carolina had ophthalmic examinations and serum leptospiral microscopic agglutination test (MAT) titers performed every 3-6 months for 24 months followed by a final examination at 34 months. Unassigned: Throughout the nearly three-year study period, 17 horses (34%; 17/49 horses) developed signs of uveitis; 20 eyes (20/34; 58.8%) of these 17 horses were visual at the initial examinati...
Larsen MME, Eriksson A, Impellizeri JA.To describe the procedure and outcome of electrochemotherapy (ECT) with bleomycin as a first-line treatment for bilateral ocular surface squamous neoplasia (OSSN) in the eye of a horse. Methods: A client-owned 5-year-old Haflinger gelding with limbal-conjunctival squamous cell carcinoma. Methods: During general and local anesthesia, injection of bleomycin in the ocular tumor was followed by electroporation, applied with a 15 mm needle electrode, needles held parallel to the ocular surface. Results: Treatment with ECT resulted in therapeutic electric pulses and complete tumor response with no...
Farkas A, Thieme K, Soimala T, Jensen CK, Eule JC.This retrospective study evaluates the efficacy of povidone-iodine (PI) and polyhexamethylene biguanide (PHMB) as preoperative antiseptics in equine ophthalmic procedures. Methods: Horses that underwent routine ophthalmic surgery and procedures. Methods: Data were collected retrospectively from the medical records of equine patients undergoing ophthalmic procedures. Inclusion criteria were sampling for aerobic microbial culture at three different time points (T0: pre-irrigation, T1: post-irrigation, and T2: postoperatively) and T0 showing bacterial growth. Microbiological outcomes were assesse...
Morris JM, Lassaline ME, Nunnery CM, Teixeira LBC, Martins BC, Moore BA, Knickelbein KE, Scherrer NM, Plummer CE.Little information describing the biologic behaviour and therapies for corneal lymphoma exist. Objective: To characterise histologically confirmed equine corneal lymphoma considering breed, age or sex predisposition, histologic and immunologic features, therapies and outcomes. Methods: Retrospective case series. Methods: A multicentre retrospective medical record review was used to identify horses that presented with corneal disease confirmed morphologically as corneal lymphoma from 2012 to 2022. Results: Mean age at diagnosis was 10.5 years. Males represented 18/26 cases. Warmblood (14) and...
Sano Y, Miura C, Kinoshita Y, Kakimoto M, Tsuda T, Matsuda K.Congenital cystic eye (CCE) is a rare congenital ocular disease, which has been suggested to be caused by problems with optic vesicle invagination. This is characterized by the formation of intraorbital cystic lesions lined by undifferentiated neuroepithelium. However, cases involving ocular structures with varying degrees of differentiation have also been reported as CCE in humans and animals. In horses, CCE have only been reported as a case presenting as neuroepithelial-lined cysts without the formation of ocular structures. This paper describes large bilateral intraorbital cysts in a 1-day-...
Allen R, Goodhead AD.Warmblood horses are a popular breed around the world for equestrian sports. Previous studies have investigated ocular findings in other breeds of horses; however, no studies exist for the Warmblood breed. Objective: To determine the prevalence of ocular abnormalities in a convenience sample of Warmblood horses in South Africa and to determine if the prevalence of lens and chorioretinal lesions increase with age. Methods: Descriptive, observational study. Methods: Warmblood horses underwent a full ophthalmic examination which included a Schirmer tear test (STT), tonometry, fluorescein dye test...
Kiesse O, Torgerson P, Pot SA, Stadler S.A retrospective data analysis was performed on 17 eyes from 13 horses which underwent a sub-Tenon's injection to facilitate phacoemulsification or pars plana vitrectomy under general anesthesia between 2018 and 2022. All procedures were performed by the same veterinary ophthalmologist. Seven eyes received a sub-Tenon's dose of 7 ml lidocaine (XylocainÒ, 2 % lidocaine hydrochloride, Germany, Aspen Germany GmbH), and 10 eyes received 7 ml mepivacaine (MepinaestÒ purum 2 %, mepivacaine hydrochloride, Switzerland, Gebro Pharma GmbH). Statistical analysis compared onset and duration of gl...
McMullen RJ.To review data on the advances in equine ophthalmic imaging that have been made during the past 5 years and highlight advantages of using multiple imaging modalities to improve clinical observational skills and improve diagnostic accuracy. Methods: A literature review from 2019 through 2024 of equine ophthalmic digital photography, fundus photography, ocular and orbital ultrasonography (US), ultrasound biomicroscopy (UBM), confocal microscopy (CM), spectral domain optical coherence tomography (SD-OCT), radiography, CT, and MRI. Results: Digital photography remains the cornerstone of equine oph...
Smith HL, Love KR, Antezana A, Barr EM, Gilger BC, Oh A.To determine clinical outcome, treatment costs, and hospitalization duration in horses treated for keratomycosis and identify ophthalmic examination and diagnostic results associated with these outcomes. Methods: This was a retrospective study of 126 equine keratomycosis cases between 2004 and 2020 with fungal infection confirmed on cytology, culture, and/or histopathology and a minimum of 1-month follow-up. Details of the ophthalmic examination, diagnostic test results, and treatment and cost outcomes were recorded. Outcomes of interest were analyzed by treatment type. The relationship of pat...
D'Agostino AL, Giuliano EA, Kuroki K, Martin LM.To describe the first report of third eyelid cartilage eversion in an adult American Quarter Horse mare. Methods: A 22-year-old American Quarter Horse mare presented to the University of Missouri Veterinary Health Center Equine Hospital for a 2-week history of a third eyelid cartilage abnormality of the left eye with no known recent trauma. Complete ophthalmic examination revealed third eyelid cartilage eversion of the left nictitans. The abnormal scrolled cartilage was surgically excised using a handheld cautery unit and submitted for histopathologic evaluation. Results: Histopathologic findi...
Labelle AL, Gemensky Metzler AM, McMullen RJ, Wiggans KT, Labelle P, Hamor RE.To describe the clinical appearance, histopathology, and treatment of equine intraocular melanocytic neoplasia in adult horses. Unassigned: A retrospective review of medical records was conducted. Data recorded included signalment, ocular examination findings, physical examination findings, therapeutic interventions, and case outcomes. Histopathologic characteristics of enucleated globes were evaluated. A Student's -test was used to evaluate differences in the interval from diagnosis to last known outcome between horses receiving therapeutic interventions and horses undergoing monitoring alone...
Moody LM, Hicks SL, Foote BC, Hendrix DV, Ward DA.Equine corneal disease is common and painful. Current pain mitigation strategies are often suboptimal, especially early in the disease. Objective: To evaluate the effects of local anaesthetic delivery via indwelling retrobulbar catheter on corneal sensitivity, pupil size, pupillary light responses (PLRs), and ocular motility in normal horses. Methods: Randomised, controlled crossover experiment. Methods: One eye was randomly selected from seven horses. A 20-gauge catheter was placed in the retrobulbar space and injected with 10 mL of 0.5% bupivacaine or 0.9% saline. Cochet-Bonnet esthesiomet...
Gupta RC, Lall R, Srivastava A, Sinha A.Hyaluronic acid (also known as hyaluronan or hyaluronate) is naturally found in many tissues and fluids, but more abundantly in articular cartilage and synovial fluid (SF). Hyaluronic acid (HA) content varies widely in different joints and species. HA is a non-sulfated, naturally occurring non-protein glycosaminoglycan (GAG), with distinct physico-chemical properties, produced by synoviocytes, fibroblasts, and chondrocytes. HA has an important role in the biomechanics of normal SF, where it is partially responsible for lubrication and viscoelasticity of the SF. The concentration of HA and its ...
Arkill KP, Winlove CP.(1) To establish whether the tidemark and calcified cartilage are permeable to low molecular weight solutes, thereby providing a potential pathway for nutrition of cells in the deep cartilage. (2) To investigate transport from the subchondral microcirculation into calcified cartilage in an intact perfused joint and the effects on transport of static loading. Methods: The permeability of the tidemark and calcified cartilage was investigated in plugs of cartilage and subchondral bone which formed the membrane of a diffusion cell. Transport from the subchondral microcirculation and the effects of...
Gerding JC, Gilger BC.Equine recurrent uveitis (ERU) is a leading cause of vision loss in horses. Objective: To assess the prognosis and impact of ERU on affected horses and their owners by evaluating the signalment, treatment and outcome (including the loss of use, vision assessment and economic loss). Methods: Retrospective impact study. Methods: Medical records of horses presenting to the North Carolina State University Veterinary Health Complex (NCSU-VHC) with ERU between 1999 and 2014 were reviewed. Signalment, clinical signs, ophthalmic examination findings, treatments and outcomes were evaluated. Owner quest...
Nikiforov TT, Rendle RB, Goelet P, Rogers YH, Kotewicz ML, Anderson S, Trainor GL, Knapp MR.A new method for typing single nucleotide polymorphisms in DNA is described. In this method, specific fragments of genomic DNA containing the polymorphic site(s) are first amplified by the polymerase chain reaction (PCR) using one regular and one phosphorothioate-modified primer. The double-stranded PCR product is rendered single-stranded by treatment with the enzyme T7 gene 6 exonuclease, and captured onto individual wells of a 96 well polystyrene plate by hybridization to an immobilized oligonucleotide primer. This primer is designed to hybridize to the single-stranded target DNA immediately...
Balazs EA, Denlinger JL.The availability of elastoviscous solutions of highly purified hyaluronan has created two new therapeutic methods in human and veterinary medicine: viscosurgery and viscosupplementation. Viscosurgical tools and implants are widely used in ophthalmology and have been suggested for use in otology. Visco-supplementation of joint fluid using elastoviscous hyaluronan solutions is widely used in the treatment of equine traumatic arthritis. It was also suggested for use in idiopathic osteoarthritis in humans, but this application has not received wide acceptance. Cross-linked forms of hyaluronan have...
Knollinger AM, La Croix NC, Barrett PM, Miller PE.To compare intraocular pressure (IOP) measurements obtained with a rebound tonometer in dogs and horses with values obtained by means of applanation tonometry and direct manometry. Methods: Prospective study. Methods: 100 dogs and 35 horses with clinically normal eyes, 10 enucleated eyes from 5 dogs, and 6 enucleated eyes from 3 horses. Methods: In the enucleated eyes, IOP measured by means of direct manometry was sequentially increased from 5 to 80 mm Hg, and IOP was measured with the rebound tonometer. In the dogs and horses, results of rebound tonometry were compared with results of applana...
Cheng FP, Fazeli A, Voorhout WF, Marks A, Bevers MM, Colenbrander B.Peanut agglutinin (PNA) was used to assess the sperm acrosomal status and the acrosome reaction during gamete interaction in the equine species. PNA exclusively binds to the outer acrosomal membrane of stallion spermatozoa, as was established by transmission electron microscopy. Fluorescein isothiocyanate-PNA (FITC-PNA) labeling was used to monitor sperm acrosomal changes during a prolonged incubation period of 24 hours and during a 2-hours incubation in the presence of 5 microM calcium ionophore A23187. In addition, after a 4-hours preincubation in SP-TALP medium, sperm samples were incubated...
Furusawa T, Iwano H, Hiyashimizu Y, Matsubara K, Higuchi H, Nagahata H, Niwa H, Katayama Y, Kinoshita Y, Hagiwara K, Iwasaki T, Tanji Y, Yokota H....Bacterial keratitis of the horse is mainly caused by staphylococci, streptococci, and pseudomonads. Of these bacteria, Pseudomonas aeruginosa sometimes causes rapid corneal corruption and, in some cases, blindness. Antimicrobial resistance can make treatment very difficult. Therefore, new strategies to control bacterial infection are required. A bacteriophage (phage) is a virus that specifically infects and kills bacteria. Since phage often can lyse antibiotic-resistant bacteria because the killing mechanism is different, we examined the use of phage to treat horse bacterial keratitis. We isol...
Binley K, Widdowson PS, Kelleher M, de Belin J, Loader J, Ferrige G, Carlucci M, Esapa M, Chipchase D, Angell-Manning D, Ellis S, Mitrophanous K....RetinoStat(®) is an equine infectious anemia virus-based lentiviral gene therapy vector that expresses the angiostatic proteins endostatin and angiostatin that is delivered via a subretinal injection for the treatment of the wet form of age-related macular degeneration. We initiated 6-month safety and biodistribution studies in two species; rhesus macaques and Dutch belted rabbits. After subretinal administration of RetinoStat the level of human endostatin and angiostatin proteins in the vitreous of treated rabbit eyes peaked at ∼1 month after dosing and remained elevated for the duration o...
Johns IC, Baxter K, Booler H, Hicks C, Menzies-Gow N.To describe the bacterial and fungal flora of the normal conjunctiva of horses in the UK; to determine the effect of horse age, sex, geographic location, and housing on this flora; and to determine the most appropriate antimicrobial drug(s) for prophylactic treatment of corneal ulcers. Methods: A total of 60 adult healthy horses were studied. Methods: Swabs of the conjunctiva were obtained from 60 horses housed in two locations within the UK. Specimens were cultured for aerobic bacteria and fungi, and sensitivity against six ophthalmic antimicrobials assessed. The effect of age, sex, location ...
Sandmeyer LS, Breaux CB, Archer S, Grahn BH.To determine the prevalence of congenital stationary night blindness (CSNB) in Appaloosa horses in western Canada, investigate the association with the leopard complex of white spotting patterns, and further characterize the clinical and electroretinographic aspects of CSNB in the Appaloosa. Methods: Three groups of 10 Appaloosas were studied based on coat patterns suggestive of LpLp, Lplp, and lplp genotype. Methods: Neurophthalmic examination, slit-lamp biomicroscopy, indirect ophthalmoscopy, measurement of corneal diameter, streak retinoscopy, scotopic and photopic full-field and flicker ER...
Ireland JL, McGowan CM, Clegg PD, Chandler KJ, Pinchbeck GL.This study reports on aspects of preventive health care and on the prevalence of disease in geriatric (≥30 years old) horses and ponies in North-West England and North Wales. Of 128 questionnaires mailed to horse owners, 87 useable responses were received and 69 horses were subject to veterinary examination. Of the animals examined, 16% were underweight with body condition scores (BCS)3/5). This contrasted with the owner responses that reported 23% of the animals surveyed to be underweight and only 3% to be overweight. When assessed at trot, 77% of the horses were lame on at least one limb, ...
Andrew SE, Nguyen A, Jones GL, Brooks DE.To evaluate seasonal effects on the presence or absence of fungal and aerobic bacterial flora of the conjunctival fornix of normal Florida Thoroughbred horses. Methods: Both eyes of 100 horses. Methods: Horses with normal anterior segment ophthalmic examinations from three farms in north central Florida were included. Each animal had the ventral conjunctival fornix of each eye swabbed with sterile culturettes. Samples were taken in October, January, April, and July (1999-2000). Aerobic and fungal cultures were plated. Bacterial cultures were reviewed at 24 and 48 h. Fungal cultures were review...
Bussieres M, Krohne SG, Stiles J, Townsend WM.To evaluate the efficacy of using a porcine small intestinal submucosa (SIS) graft covered by a conjunctival flap for the surgical repair of full-thickness corneal wounds in dogs, cats and horses. Methods: All records dating from August 1999 to February 2003 from Purdue University Veterinary Teaching Hospital of patients that had undergone ophthalmic surgical procedures and received a SIS corneal graft for a full-thickness lesion were reviewed. Fifteen cases were identified including six dogs, two cats and seven horses. Requirements for inclusion in this study were that SIS was used as a corne...
Witkowski L, Cywinska A, Paschalis-Trela K, Crisman M, Kita J.Equine recurrent uveitis (ERU) has various etiologies, with Leptospira infection and genetic predisposition being the leading risk factors. Regardless of etiology, expression of ocular proteins associated with maintenance of the blood-ocular barrier is impaired in ERU. The recurring-remitting cycle of ERU repeatedly disrupts the blood-ocular barrier, allowing the previously immune-privileged ocular environment to become the site of a progressive local autoimmune pathology that ultimately results in tissue destruction and vision loss. The immune-mediated process involves humoral and cellular me...
Spiess BM.Equine recurrent uveitis (ERU) has always been and still is an important disease with a significant impact on the horse industry in Europe, with a prevalence of 8-10%. The need to understand and manage the disease has spurred the development of veterinary ophthalmology in general, although the aetiology of the disease remains the subject of intense discussion. It is most probably an autoimmune disease triggered, at least in Europe, in the majority of cases by Leptospira spp. The therapy of ERU has evolved over the centuries from various methods of bloodletting to rational medical therapy using...
Ramsey DT, Ewart SL, Render JA, Cook CS, Latimer CA.OBJECTIVE: To determine the incidence and describe ocular abnormalities in a cross-section of the population of Rocky Mountain Horses. Design: Prospective study. Animals: Five-hundred and fourteen Rocky Mountain Horses. Procedure: Ophthalmic examinations were performed using a slit-lamp biomicroscope and an indirect ophthalmoscope. Intraocular pressures were measured by applanation tonometry. Eyes from six horses were obtained for histologic examination. RESULTS: Cysts of the posterior iris, ciliary body, and peripheral retina were detected most frequently (249 horses), and were always located...
Andersson LS, Wilbe M, Viluma A, Cothran G, Ekesten B, Ewart S, Lindgren G.Equine Multiple Congenital Ocular Anomalies (MCOA) syndrome is a heritable eye disorder mainly affecting silver colored horses. Clinically, the disease manifests in two distinct classes depending on the horse genotype. Horses homozygous for the mutant allele present with a wide range of ocular defects, such as iris stromal hypoplasia, abnormal pectinate ligaments, megaloglobus, iridociliary cysts and cataracts. The phenotype of heterozygous horses is less severe and predominantly includes iridociliary cysts, which occasionally extend into the temporal retina. In order to determine the genetic ...
Gilger BC.Equine recurrent uveitis (ERU) is a common disease in horses in the USA. There have been many advances in the treatment of ERU; however, frequent misdiagnosis of ERU occurs in cases of primary corneal or uveal disease. It is critical to remember that primary uveitis (i.e. one bout of inflammation) is a different disease to ERU, which is an immune mediated recurrent uveitis. Standard symptomatic anti-inflammatory therapy is effective to control most cases of ERU; however, some horses require advanced therapy, such as placement of drug delivery devices or removal of the vitreous, when they fail ...
Keller RL, Hendrix DV.Bacterial ulcerative keratitis is a common and often vision-threatening problem in horses. Emerging bacterial resistance to commonly used topical antibiotics has been demonstrated. Previous antibiotic use may alter the antimicrobial susceptibility of bacterial isolates. Objective: To document aerobic bacterial isolates and associated bacterial susceptibilities from horses with ulcerative keratitis treated at the University of Tennessee between January 1993 and May 2004 and determine whether prior antibiotic therapy affected antimicrobial susceptibility of the isolates. Methods: Medical records...
Gilger BC, Michau TM.Equine recurrent uveitis (ERU) is one of the most common causes of blindness in horses. Until recently, treatment of this condition consisted only of symptomatic therapy, typically with steroidal and nonsteroidal medications. A better understanding of the disease process(es) has permitted new medical and surgical therapies that have recently been described. This article highlights clinical features of ERU, the causes of ERU, and new management and treatment options for horses with ERU.
Gilger BC, Wilkie DA, Clode AB, McMullen RJ, Utter ME, Komaromy AM, Brooks DE, Salmon JH.To determine the long-term efficacy, complications, and duration of effect of a cyclosporine (CsA) suprachoroidal implant (CSI) in horses with equine recurrent uveitis (ERU). Methods: Horses with ERU were treated with a 6-mm diameter, 25 mg, reservoir matrix CsA implant in the deep sclera adjacent to the suprachoroidal space. Horses with follow-up >1 year were examined for frequency of uveitis episodes, complications, and vision at last recheck. Results: Data from 151 eyes of 133 horses from the USA and Europe that had CsA devices implanted for ERU were reviewed. Follow-up time ranged from 13 ...
Ilginis T, Clarke J, Patel PJ.The last two decades have seen a revolution in ophthalmic imaging. In this review we present an overview of the breadth of ophthalmic imaging modalities in use today and describe how the role of ophthalmic imaging has changed from documenting abnormalities visible on clinical examination to the detection of clinically silent abnormalities which can lead to an earlier and more precise diagnosis. Methods: This review is based on published literature in the fields of ophthalmic imaging and with focus on most commonly used imaging modalities. Results: New imaging techniques enable non-invasive eva...
Dwyer AE, Crockett RS, Kalsow CM.Recurrent uveitis, a leading cause of blindness in horses, often develops as a sequela to systemic leptospirosis. Over a 7-year period, 63 of 112 (56%) horses with uveitis were seropositive for Leptospira interrogans serovar pomona, but only 23 of 260 (9%) horses without uveitis were seropositive. Odds-ratio analysis revealed that seropositive horses were 13.2 times more likely to have uveitis than were seronegative horses. Of the 63 seropositive horses with uveitis, 59% developed blindness, compared with only 24% in the 49 seronegative horses with uveitis that lost vision in 1 or both eyes du...
Davis AB, Schnabel LV, Gilger BC.Equine immune-mediated keratitis (IMMK) leads to increased corneal opacity and inflammation secondary to an alteration of the local immune system. Bone marrow-derived mesenchymal stem cells (BM-MSC) have been shown to modulate the immune system by downregulating inflammation. Four horses with unilateral IMMK poorly responsive to traditional medical treatments underwent novel, autologous subconjunctival BM-MSC therapy. Bone marrow was harvested and processed as previously described for equine orthopedic disease. Horses received autologous subconjunctival BM-MSC injections approximately every 3-...
Priest HL, Irby NL, Schlafer DH, Divers TJ, Wagner B, Glaser AL, Chang YF, Smith MC.Borrelia burgdorferi, the etiologic agent of Lyme disease is a tick born spirochetal infection. Clinical signs of Lyme borreliosis are uncommon in horses, but when present they are often vague and nonspecific. In horses, Lyme borreliosis has been implicated in musculoskeletal, neurological, reproductive, and ocular disorders, including uveitis, but definitive diagnosis can be challenging as the causative agent is rarely isolated and serologic tests can be unreliable and do not confirm active disease. Here, we report two cases of equine uveitis associated with B. burgdorferi based on the identi...
Wollanke B, Rohrbach BW, Gerhards H.To measure antibody titers against Leptospira interrogans in serum and vitreous humor and determine the prevalence of L interrogans in vitreous humor of horses with recurrent uveitis. Methods: Cross-sectional study. Methods: 242 horses (270 eyes) with recurrent uveitis undergoing vitrectomy and 39 control horses (54 eyes) without any history or clinical signs of recurrent uveitis undergoing euthanasia or enucleation for unrelated reasons. Methods: Serum and vitreous humor were tested for antibodies against 13 serovars of L interrogans. Vitreous humor was submitted for leptospiral culture; isol...
Schnitzer J.The distribution of astrocytes has been studied in whole-mounted horse and monkey retinae by the immunocytochemical localization of glial fibrillary acidic protein (GFAP). In the horse, astrocytes were found to be restricted to a narrow zone close to the optic nerve head. This is also the only region of the horse retina that is vascularized. In the monkey, astrocytes were found ubiquitously in the nerve fiber layer of the retina, apart from the avascular fovea centralis which lacked astrocytes. These observations strongly suggest that retinal astrocytes co-occur with blood vessels, a feature w...
Reed Z, Thomasy SM, Good KL, Maggs DJ, Magdesian KG, Pusterla N, Hollingsworth SR.Equine keratomycosis in the western USA has received little study, probably owing to its low prevalence. Objective: To determine clinical features, predominant fungal isolates, treatment modalities and outcomes of horses with keratomycosis in California and compare these with results from different geographic regions. Methods: Records of horses presented to the University of California-Davis Veterinary Medical Teaching Hospital (UCD-VMTH) with confirmed keratomycosis between 1987 and 2010 were reviewed for this retrospective study. Information retrieved from the record included background, oph...
