Topic:Ophthalmology
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.
Survey of retinal haemorrhages in neonatal thoroughbred foals. Twenty-seven of 167 neonatal thoroughbred foals (16 per cent) were found to have retinal haemorrhages after a careful examination of the entire fundus. Experience in differentiating haemorrhages from other lesions, and the selection of foals from normal populations, were considered to have an important effect on their apparent incidence. Bilateral haemorrhages were more common and there was a significantly higher incidence in female foals. The numbers of haemorrhages ranged between one and 20; 36 per cent of eyes with retinal haemorrhages had the small punctate type and 56 per cent had the spl...
The effect of supramaximal exercise on equine platelet function. When blood is collected into sodium citrate in the proportion of 9 parts blood:1 part sodium citrate, the concentration of plasma sodium citrate in the sample will depend on the packed cell volume (PCV) of the blood sample. This difference in plasma sodium citrate concentration secondary to alterations in PCV significantly affects human platelet aggregation responses. Since horses attain a high PCV in response to high-intensity exercise we investigated the effect of differences in sample plasma sodium citrate concentration on equine platelet aggregability. In addition, low molecular weight hep...
Diagnostic ophthalmology. Corneal ulcer with severe secondary anterior uveitis in a pony. The study reports on the diagnosis and treatment of a severe case of corneal ulceration and anterior uveitis in a 1-year-old Norwegian fjord pony, which did not respond to initial […]
[35 leptospira isolated from the vitreous body of 32 horses with recurrent uveitis (ERU)]. 130 vitreous samples, systematically collected in 1998 from 117 horses during vitrectomy, were cultured for the presence of leptospires. All horses suffered from equine recurrent uveitis (ERU), also known as periodic ophthalmia or moon blindness, and were treated surgically to combat painful attacks, and to preserve vision. In 35 out of 130 vitreous samples (35/130 = 26.9%), leptospires could be isolated. These isolates belong to the grippotyphosa serogroup (n = 31) and to the australis serogroup (n = 4). So, for the first time, leptospires were recovered from eyes in vivo in a large number of...
Equine infectious keratitis. 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...
Subconjunctivally implanted micro-osmotic pumps for continuous ocular treatment in horses. To evaluate the feasibility of using a subconjunctivally implanted micro-osmotic pump for continuous delivery of medication to the eyes of horses- during a 7-day period. Methods: 4 healthy adult horses. Methods: With horses restrained in a standing position, micro-osmotic pumps were implanted subconjunctivally in each eye for 7 days. The treatment eye received an atropine-loaded micro-osmotic pump (100 microl of 1.5% atropine), and the contralateral eye received a sterile saline-loaded pump (100 microl of 0.9% NaCl) as a control treatment. Pupil size was measured at 12-hour intervals until val...
Systemic dexamethasone concentration in horses after continued topical treatment with an ophthalmic preparation of dexamethasone. To determine concentrations of dexamethasone in serum and urine of horses treated repeatedly with a topically administered ophthalmic dexamethasone preparation. Methods: 4 clinically normal horses (2 mares, 2 geldings). Methods: 0.1% dexamethasone ophthalmic ointment was administered to the left eye of each horse every 5 to 9 hours for 8 consecutive days, yielding an estimated cumulative dexamethasone dose of 6.4 microg/kg of body weight. Serum and urine samples were obtained before the first dexamethasone treatment, on days 4 and 8 of treatment, and 24, 48, and 96 hours after cessation of tre...
Ocular manifestations of equine motor neuron disease. The characteristics of the ocular manifestations of equine motor neuron disease (EMND) are described. Forty-two horses with histories, clinical signs and necropsies compatible with EMND were the subjects of this study. Ophthalmoscopic lesions that varied in severity were found in 40 of 42 horses and appeared as a distinct pigmented reticulated pattern at the tapetal-nontapetal junction or throughout the fundus, depending upon severity. The pattern colours ranged from yellow brown to black. Areas of hyperreflectivity formed mosaic patterns in the tapetal fundus. ERG B-wave amplitudes were usual...
Tumors of the eye and ocular adnexal tissues. This article reviews options in dealing with tumors of the cornea and conjunctiva, nictitating membrane neoplasms, and eyelid neoplasms. Orbital tumors, optic nerve and other intraocular tumors are also discussed.
[Demonstration of intraocular leptospira in 4 horses suffering from equine recurrent uveitis (ERU)]. Vitreous samples from 43 horses which underwent vitrectomy because of equine recurrent uveitis (ERU) were cultured for leptospires. Out of 4 vitreous samples (4/43 = 9%), leptospires could be isolated. In 3 cases, serovar grippotyphosa, and in one case, a serovar out of the serogroup Australis were identified. So for the first time, in several horses with ERU in vivo cultures of vitreous material were positive for leptospires. A strong evidence of association between leptospiral infection and uveitis is discussed for many years. In this investigation the leptospiral etiology is confirmed. Vitr...
Progesterone-induced acrosome reaction in stallion spermatozoa is mediated by a plasma membrane progesterone receptor. The aim of the present study was to investigate whether the induction of stallion sperm acrosome reaction (AR) by progesterone is mediated by binding of progesterone to a receptor on the sperm plasma membrane or to an intracellular progesterone receptor. Progesterone-BSA conjugate labeled with fluorescein isothiocyanate (P-BSA-FITC) in combination with a vital stain, ethidium homodimer, was applied to visualize the presence of the progesterone receptor on living spermatozoa. Alternatively, an indirect immunofluorescence technique employing a monoclonal antibody (C-262) against human intracellu...
Ocular lesions in horses with lymphosarcoma: 21 cases (1977-1997). To determine the most common ocular lesions in horses with lymphosarcoma. Methods: Retrospective study. Methods: 79 horses histologically confirmed to have lymphosarcoma. Methods: Ophthalmic examinations were performed by a single individual. Results: 21 of 79 horses had lesions involving the eye or ocular adnexa. Infiltration of the palpebral conjunctiva and eyelids was the most common lesion (n = 11). Other lesions included uveitis (n = 4), corneoscleral masses (2), third eyelid masses (2), and diffuse retrobulbar infiltrates (2). Conclusions: In horses with lymphosarcoma, ocular lesions may...
Antimicrobial susceptibility patterns of fungi isolated from horses with ulcerative keratomycosis. To evaluate in vitro susceptibility to topical antifungal medications, as measured by minimum inhibitory concentration (MIC) and 50% inhibitory concentration (IC50%), of fungal isolates from horses with ulcerative keratomycosis in Florida; to compare results with those of other studies to identify differences in susceptibility patterns among fungi isolated from horses in different geographic regions; and to note indications of fungal resistance to drugs tested in other studies. Methods: Corneal fungal cultures from client-owned horses from Florida with ulcerative keratomycosis (n = 22). Method...
Ocular tuberculosis in a horse. This paper is the first report of systemic tuberculosis involving the eyes in a horse. The animal lost condition and gradually became increasingly blind in both eyes; it was eventually euthanased. The pathological findings included bilateral, mycobacterial granulomatous uveitis with unilateral retinal detachment and necrosis, and disseminated, mycobacterial granulomatous foci in the myocardium, lungs, bronchial lymph nodes, kidneys, liver, pancreas, colon and visceral serosal surfaces, with the most extensive lesions in the myocardium. The mycobacteria were identified as Mycobacterium avium.
Complications associated with use of a one-hole subpalpebral lavage system in horses: 150 cases (1977-1996). 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...
Neodymium:yttrium-aluminum-garnet laser treatment of cystic granula iridica in horses: eight cases (1988-1996). To determine clinical features of cystic granula iridica in horses and outcome of horses treated with an ophthalmic neodymium:yttrium-aluminum-garnet (Nd:YAG) laser. Methods: Retrospective study. Methods: 8 horses. Methods: An ophthalmic Nd:YAG laser was used to deflate cysts in all horses. Results: Horses were examined because of visual impairment (n = 5), decreased jumping performance (2), or head shaking (1). Clinical signs associated with cysts resolved in all horses after treatment. Short- and long-term complications did not develop, and cysts did not recur. Conclusions: Cystic granula ir...
Evaluation of itraconazole-dimethyl sulfoxide ointment for treatment of keratomycosis in nine horses. To evaluate the efficacy of itraconazole-dimethyl sulfoxide ointment for treatment of keratomycosis in horses in the northeastern United States. Methods: Prospective clinical trial. Methods: 9 horses (10 affected eyes). Methods: All horses treated for keratomycosis at Cornell University between July 1994 and July 1996 were included in the study. The diagnosis of keratomycosis was confirmed by cytologic examination, and all horses were treated with 0.25 ml of a 1% itraconazole-30% dimethyl sulfoxide petrolatum-based ointment, applied to the affected eye every 4 hours. Results: Topical applicati...
[Application possibilities of laser surgery in veterinary medicine. 3: Literature review and some case reports]. The transmission of the laser beam trough flexible fibers enables an endoscopic application. Since this technique is minimal invasive and often does not require general anaesthesia there is an increasing interest in the use of laser techniques-for example in equine upper respiratory tract surgery. This paper gives a review about reported laser application in the different fields of veterinary surgery with emphasis on laser practice in dermatology, ophthalmology and endoscopic laser application.
Ocular diseases of llamas: 194 cases (1980-1993). To identify ocular and adnexal diseases to which llamas in North America are susceptible, to determine prevalence of these diseases in llamas, and to compare prevalences of the major ocular diseases of llamas, cattle, and horses. Methods: Retrospective study. Methods: 194 llamas, 4,937 cows, and 11,950 horses with ocular disease. Methods: Medical records of all llamas entered into the Veterinary Medical Database between 1980 and 1993 were reviewed. Data on ocular structures affected and types of ocular disease were compiled. Prevalences of uveitis, corneal ulcers, and ocular squamous cell carc...
Corneal concentrations and preliminary toxicological evaluation of an itraconazole/dimethyl sulphoxide ophthalmic ointment. The objectives of this study were to determine the concentration of itraconazole achieved in corneal tissue and aqueous humour after topical application of a 1% itraconazole ointment: to determine the effect of including dimethyl sulphoxide (DMSO) in the ointment on achievable ocular tissue itraconazole concentrations; and to assess if any gross or histopathologic ocular toxicity results from the topical application of 1% itraconazole with or without the addition of DMSO. The experimental trial consisted of 6 horses considered to have normal eyes. Each horse had one eye treated with 0.3 mL of ...
Visual outcome and ocular survival following iris prolapse in the horse: a review of 32 cases. The medical records of 32 horses treated for iris prolapse (IP) during an 8 year period, at the University of Florida Veterinary Medical Teaching Hospital, were reviewed. Iris prolapse was associated with perforated corneal ulcers in 15 horses (47%), ruptured stromal abscesses in 2 horses (6%), and full thickness corneal lacerations in 15 horses (47%). Initial ophthalmic examinations revealed IP with severe iridocyclitis in all eyes and keratomalacia in 8 eyes with corneal ulcers, one with a stromal abscess and 1 with a corneal laceration. Hyphema was present in 7 eyes with corneal lacerations...
Use of peanut agglutinin to assess the acrosomal status and the zona pellucida-induced acrosome reaction in stallion spermatozoa. 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...
Eosinophilic keratoconjunctivitis in seven horses. Eosinophilic keratoconjunctivitis was diagnosed in 7 horses at The Ohio State University between 1976 and 1994. All horses had moderate-to-severe blepharospasm, chemosis, and conjunctival hyperemia; epiphora; and extensive yellow-to-white caseous mucoid discharge. Corneal ulcers associated with this disease were perilimbal and extended centrally. All ulcers were covered with a white necrotic plaque firmly attached to the underlying cornea. Other ophthalmic abnormalities were not detected. Corneal scrapings examined cytologically contained numerous eosinophils interspersed between epithelial ce...
Penetrating keratoplasty for treatment of recurrent squamous cell carcinoma of the cornea in a horse. Squamous cell carcinoma involving the cornea and conjunctiva of the left eye in a 14-year-old horse was treated by superficial keratectomy in combination with beta-radiation and radiofrequency hyperthermia. The tumor recurred 4 months later in the central cornea at the edge of the previous keratectomy site. Penetrating keratoplasty was performed in an effort to remove the tumor and retain a visual eye. The eye was visual 13 months after surgery. Mild fibrosis and vascularization were observed in the area of the penetrating keratoplasty.
The zygomatic branch of the auriculopalpebral nerve: can it be normally palpated in the live horse? A detailed description is given of the methods to locate and palpate a subcutaneous part of the zygomatic branch of the auriculopalpebral nerve in 9 out of 10 adult horses examined. This permits the exact placing of local anaesthetic along the nerve branch at the described site, resulting in the akinesis of the m orbicularis oculi and the elimination of the blink reflex. This facilitates ophthalmologic examination and possible treatment of some eye conditions.
[Sonographic diagnosis (B-mode techniques) for the eyes of horses. 2. Pathological cases]. 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...