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.
Myrna KE, Herring IP.To assess the efficacy and kinetics of a continuous infusion modality for topical ophthalmic drug delivery via subpalpebral lavage in horses. Methods: Five ophthalmically normal horses Methods: A constant-rate continuous delivery pump was used to apply 0.01% fluorescein solution to the eyes of five ophthalmically normal horses via subpalpebral lavage. Fluorescein was applied at a rate of 0.14 mL/h for 72 h. Tear samples were collected from the ventral conjunctival fornix at regular intervals via capillary tube and tear fluorescein concentrations were determined via spectral assay. Laboratory s...
Nunnery C, Pickett JP, Zimmerman KL.This report documents congenital stationary night blindness (CSNB) in two non-Appaloosa horse breeds (Thoroughbred and Paso Fino). History of vision impairment since birth, normal ocular structures on ophthalmic examination, and electroretinographic findings were consistent with CSNB. In one horse (Thoroughbred), a 9-year follow-up was carried out. In the Paso Fino, severe vision impairment from birth to approximately 1 year of age in both dim and bright light situations led to humane euthanasia and histopathologic confirmation of the disorder.
Brünott A, van der Velden MA.In this case report a 20-year-old horse with unilateral eosinophilic keratitis is presented. The occurrence, clinical symptoms, histological findings and treatment of this ocular disorder are described and discussed against the background of relevant literature. Local administration of 0.1% dexamethason was successful.
Gilmour MA, Clarke CR, Macallister CG, Dedeo JM, Caudell DL, Morton RJ, Pugh M.To investigate intraocular penetration of orally administered doxycycline in the normal equine eye and to compare intraocular and serum doxycycline concentrations. Procedures Six mares were administered doxycycline at 10 mg/kg every 12 h by nasogastric tube for 5 days. Blood, aqueous, and vitreous samples were collected on days 1 and 5. All samples were assayed for doxycycline concentrations. Aqueous and vitreous samples were also assayed for protein quantitation. Results: Doxycycline was rapidly absorbed after the first dose (T(max) value of 1.42 +/- 1.28 h); and elimination of doxycycline oc...
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...
Gilger BC, Michau TM, Salmon JH.The purpose of this study is to describe clinical and histologic findings, treatment, and outcome of horses with suspected immune-mediated keratitis (IMMK). Methods: Retrospective study. Methods: Nineteen horses that presented to NCSU-VTH from 1998 to 2004 with IMMK. Procedures Information retrieved from the medical records included signalment, duration of clinical signs, therapy prior to initial examination, ophthalmic abnormalities, diagnostics performed, therapy instituted, and long-term vision. Results: Nineteen horses (22 eyes) were diagnosed with IMMK. Three distinct clinical groups were...
Gilger BC, Reeves KA, Salmon JH.To measure the ocular surface area, scleral thickness, and the aqueous and vitreous humor volumes in the canine and equine eye. Animals studied Fourteen canine and 16 equine cadaver eyes. Methods: Eyes were measured either fresh or following fixation in formalin. Ocular surface area was calculated using the fluid displacement method. Globes were hemisected and aqueous and vitreous humor were collected and quantitated. Scleral thickness was measured by digital caliper, by image projection, and by ultrasonic biomicroscopy (UBM). Results: Mean +/- standard deviation (SD) scleral surface areas in ...
Bosch G, Klein WR.To determine the usefulness and clinical outcome of a combined procedure of superficial keratectomy and cryosurgery as a treatment for limbal neoplasms in horses. Methods: Retrospective study. Methods: Thirteen horses with 14 limbal tumors. Methods: Medical records of all patients with limbal tumors, referred to the Department of Equine Sciences of Utrecht University between 1995 and 2002, were retrieved. Patient data were analyzed with respect to signalment, tumor surface area and histologic diagnosis. Surgery, performed under general anesthesia, included surgical debulking of the tumor follo...
Gemensky-Metzler AJ, Wilkie DA, Kowalski JJ, Schmall LM, Willis AM, Yamagata M.To determine effects of topical antimicrobial and antimicrobial-corticosteroid preparations on the ocular flora of horses. animals: 40 horses. Methods: One eye was treated 3 times daily for 2 weeks with one of the following ointments: (1) neomycin-bacitracin-polymyxin B, (2) 0.6% prednisolone-0.3% gentamicin, (3) neomycin-polymyxin B-0.05% dexamethasone, or (4) treated (artificial tears) control. Contralateral eyes of treated control eyes served as untreated control eyes. Corneal and conjunctival specimens for bacterial and fungal cultures were collected prior to initiation of treatment, after...
Kaps S, Richter M, Philipp M, Bart M, Eule C, Spiess BM.A 12-year-old Haflinger gelding was presented to the veterinary medical teaching hospital of the University of Zurich with a light-pink raised mass on the temporal limbus and conjunctiva of the left eye. Squamous cell carcinoma was confirmed histologically after keratectomy and cryotherapy. Seven months later, a smooth pink, progressively enlarging mass was observed within the cornea of the left eye. Ultrasonographically, the mass was not only infiltrating the corneal stroma but seemed to protrude into the anterior chamber. The globe was surgically removed and submitted for pathology. A histol...
Rohrbach BW, Ward DA, Hendrix DV, Cawrse-Foss M, Moyers TD.To evaluate the effect of vaccination against leptospirosis on frequency and days to recurrence of uveitis and progression of disease in horses with equine recurrent uveitis (ERU). Methods: Forty-one horses with ERU. Methods: Horses were randomly assigned to experimental (vaccinated) or control groups. Vaccine containing six serovars of Leptospira or placebo was administered, an ophthalmic examination performed and blood samples drawn on days 0, 28, 180 and 365. Antibody titers were measured against each serovar. Recurrence of uveitis was verified by ophthalmic examination. Results of the init...
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...
Saroglu M, Aktas M, Olgun D, Arun SS.A tumor-like tissue mass of lateral-limbal site in the right eye of a 12-year-old Cob Pony mare was presented for surgical removal. The mass, covering the lateral limbus, bulbar conjunctiva and part of the cornea, was surgically removed, and the corneal defect repaired with a pedicle bulbar conjunctival graft. The mass was inflammatory in nature containing mononuclear cells. No recurrence or complication occurred at 6- and 12-month follow-up examination.
Stoppini R, Gilger BC, Malarkey DE, Ratto A, Brigati G.A Russian jumper horse presented because of an ocular perilimbal conjunctival mass and, on clinical examination, two bilateral conjunctival masses were found, of different size and conformation. Attempts at complete excision of the left eye mass and excisional biopsy of the right eye mass were performed. The left eye mass recurred rapidly, but resolved completely after topical corticosteroid therapy. The two lesions had similar histopathologic features, characterized by focal, chronic, primarily lymphocytic conjunctivitis with follicular lymphoid hyperplasia. Special histopathologic staining t...
Mosunic CB, Moore PA, Carmicheal KP, Chandler MJ, Vidyashankar A, Zhao Y, Roberts RE, Dietrich UM.To determine the effects of treatment with and without adjuvant radiation therapy on recurrence of ocular and adnexal squamous cell carcinoma (SCC) at specific anatomic locations in horses. Methods: Retrospective study. Methods: 91 horses. Methods: Medical records of horses with histologically confirmed ocular and adnexal SCC evaluated from 1985 to 2002 were reviewed. Sex, breed, age, type of treatment, location, and recurrence of SCC were recorded. Two treatment groups determined by recurrence of SCCs treated with and without adjuvant radiation therapy were established. Results: The anatomic ...
McCowan C, Stanley RG.Abstract A heavily pigmented tumor was removed from the lateral, perilimbal, bulbar conjunctiva of a bay Thoroughbred horse. Excision was incomplete and the base of the tumor was lasered on the assumption that the tumor was a melanoma. No other ophthalmic lesions were seen. Histology showed the mass to be a pigmented squamous cell carcinoma (SCC). The prognosis and recommended treatment protocols are different for SCC and melanoma. This is, to the best of our knowledge, the first report of an ocular, pigmented SCC in the veterinary literature.
Rothschild CM, Sellon DC, Bryan GM, Gay JM, Hines MT.The objectives of this study were to observe the effects of trimethoprim-sulfadiazine on equine tear production and to determine normal fluctuations in Schirmer tear test (STT) values in horses. A randomized, placebo-controlled, blinded clinical trial measuring STT values in 15 horses over an 8-week period was performed. The treatment group (eight horses) received 30 mg/kg trimethoprim-sulfadiazine orally once a day and the control group (seven horses) received placebo (flour) at the same time. All horses were housed outdoors throughout the study. Schirmer tear test values were measured at 0, ...
Evans K, Smith M, McDonough P, Wiedmann M.A retrospective study was conducted to determine case histories, microbiological characteristics, and molecular subtypes associated with Listeria monocytogenes infections of the eye in large animals. For selected cases, environmental L. monocytogenes contamination patterns on case farms were also evaluated to probe for potential sources and spread of listerial eye infections. Records of 170 L. monocytogenes isolates from animal infections were reviewed to determine the fraction of isolates associated with eye infections (conjunctivitis, keratitis, and uveitis) of animals and to gather informat...
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...
Gemensky-Metzler AJ, Wilkie DA, Cook CS.To describe semiconductor diode laser use for anterior uveal cyst deflation and coagulation in dogs, horses and cats. Methods: The presenting clinical signs, surgical technique and postoperative results for four dogs, nine horses and seven cats with anterior uveal cysts treated with diode laser are described. Treated cysts were of sufficient size and/or number to potentially impair vision, damage the corneal endothelium, or increase intraocular pressure (IOP). One dog with free-floating cysts exhibited 'fly biting' behavior. Cysts were suspected of causing shying on the affected side and/or he...
Paglia DT, Miller PE, Dubielzig RR.James Wardrop should be remembered not only as one of the founders of ocular pathology but also for his contributions to the field of comparative ophthalmology. He described a "specific inflammation" that veterinarians today know as equine recurrent uveitis. As described by Wardrop in the 19th century, this condition is known today to eventually lead to blindness.
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.
Denis HM.Corneal disease is common in equine ophthalmology and requires vigilant monitoring and appropriate therapy to optimize the outcome. Many equine corneal diseases, particularly those that progress rapidly, may benefit from surgical intervention. These include descemetoceles, deep corneal lacerations and ulcers, corneal perforation/iris prolapse, ulcerative keratitis, corneal stromal abscesses, and corneoscleral neoplasia. Indications for corneal transplantation include optical, tectonic, therapeutic, and cosmetic purposes. Corneal transplantation is most often implemented in equine patients for ...
Matthews AG.It is conservatively estimated that some form of lens opacity is present in 5% to 7% of horses with otherwise clinically normal eyes.These opacities can range from small epicapsular remnants of the fetal vasculature to dense and extensive cataract. A cataract is defined technically as any opacity or alteration in the optical homogeneity of the lens involving one or more of the following: anterior epithelium, capsule, cortex, or nucleus. In the horse, cataracts rarely involve the entire lens structure (ie, complete cataracts) and are more usually localized to one anatomic landmark or sector of ...
Michau TM, Gilger BC.Effects of traumatic injury or inflammation on the equine eye can be catastrophic. These ocular conditions can frequently result in blindness or chronic pain. In addition to blindness and pain, permanent unsightly cosmetic defects can occur. This article addresses options available for improved cosmetic outcome in horses with ocular scars or requiring enucleation. Many of these options have been described in detail previously. New information has been added to the discussion of each option where pertinent.
Wilkie DA, Gilger BC.Glaucoma is a diverse group of vision-impairing disorders that have as a common bond an elevation of intraocular pressure(IOP) to a level incompatible with the health of the eye. Glaucoma can be congenital, primary, or secondary. Congenital equine glaucoma is associated with developmental abnormalities of the iridocorneal angle or, in many cases, with the more severe anterior segment dysgenesis.
Carastro SM.This article is intended to provide the practitioner with a succinct but complete source regarding equine orbital and ocular anatomy,instrumentation available for ophthalmic examination, a methodical examination technique, sedation and regional nerve blocks, and diagnostic procedures involving the eye. Such knowledge of orbital and ocular anatomy is essential to allow recognition of normal,normal variations, or an abnormality of the equine eye and orbit.
Matas Riera M, Donaldson D, Priestnall SL.The aim of this article was to describe Descemet's membrane detachment (DMD) following phacoemulsification in five equine eyes and to review the human literature on this topic. In the last decade, there has been increased reporting of DMD in the human literature, in particular following cataract surgery. The natural history of DMD remains unknown and although various medical and surgical treatments have been advocated there is no recognized 'gold standard' treatment for DMD. This case series reports the diagnosis of DMD in four horses (5 eyes) in association with phacoemulsification surgery. T...
Hermans H, Lloyd-Edwards RA, Ferrão-van Sommeren AJH, Tersmette AA, Schouten JCM, Serra Bragança FM, van Loon JPAM.In standing ophthalmic surgery in horses, a retrobulbar nerve block (RNB) is often placed blindly for anesthesia and akinesia. The ultrasound (US)-guided RNB may have fewer complications, but the two techniques have only been compared once in equine cadavers. This study compares the techniques for success and complication rates and analyzes the effect of training on US guidance. Twenty-two equine cadavers were divided into three groups: blind RNBs were performed bilaterally in eight cadavers, US-guided RNBs were performed bilaterally in seven cadavers, and after US-guided training, blind RNBs ...
Buyukmihci NC, MacMillan A, Scagliotti RH.Mass-like lesions of the iris were evaluated in 15 horses or ponies of various ages and breeds. Breed or gender predilection was not found. These lesions were most often found in blue irides at the 12 o'clock region. Because the lesions transilluminated and changed shape rapidly with changes in pupillary size, they were hypothesized to be zones of iris hypoplasia. Histologic evaluation of one specimen supported this interpretation. The lesions were not associated with any other ocular or systemic abnormality.
Matthews AG, Poulter T.The levels of albumin, immunoglobulin G (including IgG [T]), IgA and IgM in the serum and aqueous humour of 47 horses and ponies with no ophthalmic abnormalities were determined by single radial immunodiffusion. There was a linear relationship between serum and aqueous albumin levels. No relationship of serum and aqueous IgG levels was observed. IgA was detected in only one aqueous sample. IgM was not detected in aqueous humour from any eye in this study. The factors which may influence albumin and immunoglobulin levels in normal aqueous humour are discussed.
McLaughlin SA, Whitley RD, Gilger BC.The lens represents a unique tissue in light of its embryologic development, retention of old cells and nuclear make-up, transparent nature, immune privileged status, and metabolic restrictions. Disorders of malformation and malposition occur, but cataract development is the most common and significant problem for owners and animals. Technologic and pharmacologic advances have allowed surgical removal of equine cataracts to become an acceptable alternative, capable of returning a visually impaired horse to a functional status. Uveal inflammation represents the greatest threat to successful sur...
Wotman KL, Johnson AL.Many systemic diseases have ocular manifestations. In some cases, ocular abnormalities are the most obvious or first recognized sign of disease that prompts veterinary evaluation. In other cases, the systemic disease leads to secondary ocular changes that might lead to loss of vision or globe if not addressed. Therefore, recognition of ocular abnormalities that might result from systemic diseases is an essential skill for the equine practitioner. This article provides practitioners with information regarding the most common systemic diseases of horses in North America that have ocular manifest...
Yang VY, Eaton JS, Harmelink K, Hetzel SJ, Sanchez A, Lund JR, Smith LJ.Injection techniques for retrobulbar anaesthesia are published in horses, but neither safety nor anaesthetic efficacy and duration have been evaluated objectively in vivo. Objective: To characterise the safety and efficacy of one published technique for retrobulbar anaesthesia. Methods: Randomised, controlled descriptive experiment. Methods: Unilateral retrobulbar injection with 10 mL lidocaine (2%) was performed in eight sedated adult mares. Contralateral eyes served as untreated controls. Neurophthalmic parameters, intraocular pressure (IOP), and corneal and periocular sensation were measur...
Martín-Suárez EM, Mesa P, Portillo M, Morgaz J, Moreno O, Guisado A, Galán-Rodríguez A.This study sought to compare the Schirmer Tear Test (STT)-1 results at 30 (STT30) versus 60 (STT60) seconds in healthy horses. This study included a total of 56 healthy horses. STT-1 was performed in both eyes, right eye first, and the wetting lengths were measured in STT30 and STT60. To evaluate the reduction of the initial reflex phase, the wetting length velocity was measured during the first 30 seconds. The effects of eye, age, weight, sex, and ambient temperature and humidity on STT values were evaluated. Mean (standard deviation) STT30 and STT60 were 19.06 (3.88) and 24.26 (4.50) mm. The...
Gratzek AT, Kaswan RL, Martin CL, Champagne ES, White SL.Topical cyclosporine A was safely used in a series of 11 cases of equine keratitis and keratouveitis and appeared to be an effective anti-inflammatory agent in 9 cases. The clinical diagnoses included interstitial keratouveitis, endotheliitis, multifocal punctate keratopathy and a melting stromal ulcer. In most cases, the presence or absence of insidious bacterial infection was not conclusively determined. Topical cyclosporine A had no deleterious effects in this series of cases. The authors suggest that topical cyclosporine in both aqueous and lipid base vehicles should be investigated and ev...
Dennis DA, Pinard CL, Kenney DG, Salcedo RJ, Trout DR.The standard placement of a subpalpebral lavage system may not be feasible in some horses with eyelid disease. We describe placement of a commercially available, indwelling nasolacrimal lavage system that circumvents eyelid perforation. This novel approach provided for effective delivery of drugs to 1 horse with periocular and corneal disease. . Le placement standard d’un système de lavage subpalpébral peut ne pas être réalisable chez certains chevaux atteints de maladies oculaires. Nous décrivons le placement d’un système de lavage nasolacrymal à demeure qui évite la perforation d...
Bauer BS.Although not comprehensive of all ocular conditions in the equine species, this article concentrates on various ophthalmic conditions observed in the horse where laboratory diagnostics are recommended. The importance of laboratory diagnostic testing cannot be underestimated with equine ophthalmic disease. In many cases, laboratory diagnostics can aid in obtaining an early diagnosis and determining appropriate therapy, which in turn, can provide a better prognosis. In unfortunate cases where ocular disease results in a blind, painful eye necessitating enucleation, light microscopic evaluation i...
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...
Myrna KE.This article provides a brief, clinically relevant review of neurologic disorders of the eye. A description of the neuro-ophthalmic examination is provided. Stepwise descriptions of the most common neuro-ophthalmic abnormalities are provided along with common rule outs.
Alling CR, Cremer J, Liu CC, Lewin AC, Camacho-Luna P, Carter RT.To evaluate changes in intraocular pressure (IOP) with variable head position in healthy, anesthetized horses in hoisted inversion and to assess the influence of various cofactors (age, sex, body weight, body condition score, and neck length) on IOP changes during hoisting. Methods: Seventeen healthy adult horses without significant ocular abnormalities. Methods: Subjects were administered intravenous xylazine/butorphanol premedication and ketamine/midazolam induction with xylazine/ketamine boluses for anesthetic maintenance. While hoisted, IOP was measured in triplicate for each eye via rebou...
Stonex TM, Zibura AE, Andres M, Gilger BC, Oh A.To describe the use of 1% polidocanol as the sole treatment for a superficial orbital venous malformation in a horse. Methods: A 23-year-old Welsh Cobb cross gelding with a distensible swelling affecting the left lower eyelid, and secondary palpebral margin abnormalities and superficial keratitis. Methods: Color flow Doppler ultrasonography revealed non-pulsatile blood flow within the tortuous vascular network most consistent with a superficial orbital venous malformation appearing to involve the lateral palpebral and transverse facial veins. An intravenous catheter was placed within the later...
Cichocki BM, Myrna KE, Moore PA.To describe and evaluate a modified penetrating keratoplasty technique utilizing ACell® for management of equine deep stromal or full-thickness corneal stromal abscesses (SA). Methods: Cases presenting to the University of Georgia Ophthalmology service for surgical management of SA necessitating penetrating keratoplasty (PK) were included in the study population. Surgery entailed the use of an ACell® disk sutured within the deep level of a stepped full-thickness corneal incision with an overlying conjunctival pedicle flap placed in the superficial step incision. Patients were evaluated for s...
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). ...
Ing S.A 22-year-old miniature horse gelding was brought to a veterinary clinic with multiple porcupine quills embedded in the face. One quill had perforated through the left caudoventral cornea but did not extend beyond the anterior chamber. The horse was referred to a specialist clinic for removal of the intraocular quill and subsequent primary surgical repair of the corneal wound. Following aggressive medical treatment, the horse retained vision. Piquants de porc-épic oculaires et faciaux chez un cheval miniature. Un cheval hongre miniature de 22 ans a été amené à une clinique vétérinaire a...
Czerwinski SL, Lyon AW, Skorobohach B, Léguillette R.Ophthalmic antibiotic therapy in large animals is often used empirically because of the lack of pharmacokinetics studies. The purpose of the study was to determine the pharmacokinetics of topical tobramycin 0.3% ophthalmic solution in the tears of normal horses using an automated immunoassay analysis. Results: The mean tobramycin concentrations in the tears at 5, 10, 15, 30 minutes and 1, 2, 4, 6 hours after administration were 759 (±414), 489 (±237), 346 (±227), 147 (±264), 27.6 (±28.4), 14.8 (±66.6), 6.7 (±18.6), and 23.4 (±73.4) mg/L. Mean tobramycin concentration was maintained abo...
Matheis FL, Birkmann K, Ruetten M, Pot SA, Spiess BM.A 10-year-old German Warmblood gelding was referred to the Equine Department of the Vetsuisse Faculty, University of Zurich, Switzerland, for an iris mass OD, lethargy, intermittent fever, and coughing. Ophthalmic examination revealed a 7 × 9 mm raised, fleshy, whitish to pinkish, vascularized iris mass at the 2 o`clock position OD. Fundic examination showed multifocal round, brown to black, slightly raised lesions with indistinct margins and a surrounding hyperreflective zone OU. Physical examination revealed a temperature of 39.2 °C, sinus tachycardia, preputial and ventral edema, and an e...
Lores M, Rakestraw P, De Rijck M, Yarbrough T.Application of an autogenous fascia lata graft in the treatment of keratomalacia in the horse has not been reported. The present case describes the use of an autologous fascia lata graft to surgically treat a complicated corneal ulcer in a horse. Methods: A 12-year-old Arabian mare was admitted to Sharjah Equine Hospital with a history of right eye ulcerative keratitis of unknown duration. Following a week of aggressive medical treatment, the condition deteriorated and a keratectomy and pedicle conjunctival graft were performed. A week later, the conjunctival graft partially dehisced and the u...
Mackenzie CJ, Carslake HB, Robin M, Kent RJ, Malalana F.An 8-year-old mare was presented for investigation of a 1-month history of blepharospasm, eyelid swelling, corneal edema, and ocular discharge of the right eye (OD). Ophthalmic examination confirmed mucopurulent ocular discharge, conjunctival hyperemia, and a dry, dull appearance to the cornea OD. Schirmer tear test results confirmed an absence of tear production OD (0 mm/min) consistent with keratoconjunctivitis sicca. Treatment with topical 0.2% cyclosporine A resulted in an improvement in clinical signs. An episcleral cyclosporine A implant was placed under standing sedation 5 days after in...
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...
Halse S, Pizzirani S, Parry NM, Burgess KE.A 3-year-old Marwari mare was presented for evaluation of an irregular, reddish mass protruding from behind the right third eyelid. The mass appeared to arise at the ventral limbal area, involved the perilimbal bulbar conjunctiva and widely extended into corneal tissue. No other ocular or systemic abnormalities were detected at the time of presentation. The mass was surgically removed by lamellar keratectomy, with defocused CO(2) laser used as adjunctive therapy to treat the surgical exposed area and its surroundings. Histopathologic evaluation showed sheets of densely packed, well-differentia...
Harrington JT, McMullen RJ, Clode AB, Gilger BC.A 2-month-old, 110-kg Saddlebred filly presented for evaluation of bilateral cataracts. A hypermature cataract in the left eye (OS) and an incipient nuclear cataract in the right eye (OD) were diagnosed. Electroretinography and ocular ultrasound revealed no contraindications for surgical removal of the cataractous lens OS. Phacoemulsification and implantation of a +14 diopter (D) intraocular lens (IOL) OS were performed at 4 months of age without complication, with the exception of a partial iridectomy performed on a small iris section that prolapsed through the corneal incision. Complete opht...
Gordon E, Stang BV, Heidel J, Poulsen KP, Cebra CK, Schlipf JW.To determine if corneal epithelial cell integrity is detrimentally affected by short-term administration of 1.0% morphine sulfate. Additionally, we sought to determine if topical 1.0% morphine applied to the equine cornea would result in ocular or systemic absorption. Methods: Six healthy horses. Methods: Morphine sulfate (1.0%) was applied topically to one eye every four hours for 72 h before horses were euthanized. Serum samples were collected at varying time points during the study and aqueous and vitreous humor were collected immediately after euthanasia. Morphine quantification in serum, ...
Sano Y, Matsuda K, Okamoto M, Takehana K, Hirayama K, Taniyama H.Antigen-presenting cells (APCs) in the uveal tract participate in ocular immunity including immune homeostasis and the pathogenesis of uveitis. In horses, although uveitis is the most common ocular disorder, little is known about ocular immunity, such as the distribution of APCs. In this study, we investigated the distribution of CD163-positive and MHC II-positive cells in the normal equine uveal tract using an immunofluorescence technique. Eleven eyes from 10 Thoroughbred horses aged 1 to 24 years old were used. Indirect immunofluorescence was performed using the primary antibodies CD163, MHC...
Droutsas K, Giachos I, Katsiampoula V, Kourti P, Kymionis G, Petrou P.To describe the off-label use of lyophilized equine pericardium for tectonic enhancement of the sclera in a case of progressive scleromalacia perforans. Methods: An 82-year-old woman with a history of varicella zoster virus sclerokeratitis presented with a progressively expanding scleral thinning at the superonasal quadrant of the anterior sclera of her left eye. The eye was blind because of intractable glaucoma. To avoid perforation of the exposed choroid, a single layer of lyophilized equine pericardium was sutured over the scleral perforation. After performing a conjunctival peritomy in the...
Scherrer NM, Hopster K.To study the surgical, anesthetic and recovery qualities of horses receiving either a neuromuscular blocking agent (atracurium) or intravenous lidocaine (treatment groups A and L, respectively). Methods: A total of thirty horses presented for ocular surgery were used in this study. Methods: Horses were randomly assigned to receive either atracurium (group A) or a lidocaine constant rate infusion (group L). Surgical quality was graded on a scale from 1 (excellent)-5 (poor). While anesthetized, the heart rate, oxygen saturation and mean arterial blood pressure, and end-expiratory carbon dioxide ...
Mettenleiter EM.Diagnosis of diseases of the inner eye of horses is problematic, especially in cases where ophthalmoscopic examination is impaired or prevented by cloudiness of the optical apparatus. In addition, examination of retrobulbar affection normally only allows indirect conclusions on localization and extent of alteration. By the use of ultrasound on diseased horse eyes a detailed examination of the inner eye with retrobulbar structures is possible even in these cases. Here, we present several clinical pictures which are difficult or impossible to diagnose by ophthalmoscopical means. For example, son...
