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.
Brooks DE, Plummer CE, Mangan BG, Ben-Shlomo G.To describe clinical findings in equine subepithelial keratomycosis (SEK). Methods: Retrospective medical records study. Methods: Medical records of horses that had subepithelial keratomycosis (SEK) at the University of Florida Veterinary Medical Center from 2007 to 2011 were reviewed. Methods: Data collected from the medical records included signalment, clinical descriptions of ocular lesions, diagnostic techniques, and therapeutic outcomes. Results: Twenty-one horses, consisting of three Quarter horse geldings, two Morgan geldings, one Morgan mare, two Arabian mares, three Arabian geldings, ...
Rull-Cotrina J, Molleda JM, Gallardo J, Martín-Suárez E.To assess the refractive state of the equine eye utilizing retinoscopy. To compare the refractive state of Spanish Thoroughbred horses with the refractive state of Crossbred horses. Methods: The refractive state of 135 horses (264 eyes) was assessed utilizing streak retinoscopy. Two perpendicular meridians were examined in order to assess astigmatism at a working distance of approximately 67 cm. A group of 81 Spanish Thoroughbred horses was compared with a group of 54 Crossbred horses. Cyclopentolate ophthalmic solution was instilled in the eyes of a group of 18 horses to determine if accommod...
Finno CJ, Aleman M, Ofri R, Hollingsworth SR, Madigan JE, Winfield L, Bannasch DL.Neuroaxonal dystrophy (NAD) is a disease characterized by the sudden onset of neurologic signs in horses ranging from 4 to 36 months of age. Equine degenerative myeloencephalopathy (EDM), a disease that has been associated with low vitamin E concentrations, is considered a more advanced form of NAD. The objective of this report is to describe the electrophysiological features of NAD/EDM in American Quarter horses (QHs). HORSES: Six NAD/EDM-affected QHs and six unaffected QHs were evaluated by ophthalmic examination and electroretinography. Five of the NAD/EDM-affected QH and five unaffected QH...
Galera PD, Brooks DE.Keratomycosis in the horse exists in several unique clinical forms. This paper discusses the diagnosis and clinical management of keratomycosis in the horse associated with tear film instability, epithelial keratopathy, subepithelial infiltrates, superficial and deep ulcers, plaques, melting ulcers, descemetoceles, iris prolapse, and stromal abscesses. Prompt diagnosis and aggressive treatment of equine keratomycosis can make a major difference in the maintenance of a cosmetic and visual eye.
Dwyer AE.Equine practitioners examine patient eyes on a daily basis. Indications range from inspection of normal anatomy to treatment of traumatized eyes to workups of sight threatening inflammatory or neoplastic ocular conditions. Assessment of equine eyes requires practitioners to take time to create a good "exam room" in the field and administer appropriate restraint, sedation and/or regional anesthesia to facilitate thorough examination. Accurate diagnosis and treatment of equine eye problems requires skill in ocular surface staining and cytology, and basic proficiency in standing surgery. Expertis...
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...
Santos M, Gutierrez-Nibeyro S, Stewart A, Hyde R, Rodgerson D.The clinical, diagnostic and therapeutic features of a horse with a wooden foreign body embedded in the deep portion of the right masseter muscle adjacent to the right orbit are presented. The purpose of this report is to describe the clinical presentation, magnetic resonance imaging findings and treatment of a penetrating wooden foreign body in a horse that had no history of trauma or evidence of a puncture wound. This report documents the usefulness of magnetic resonance imaging to detect a wooden foreign body embedded in the soft tissues of a horse with a chronic copious ocular discharge. T...
Greenberg SM, Plummer CE, Brooks DE, Craft SL, Conway JA.An 8-year-old Gypsy Vanner gelding presented to the University of Florida Ophthalmology service for the evaluation of chronic, recurrent corneal ulcers behind the third eyelid of the right eye. On ophthalmic examination, a cluster of aberrant hairs was identified growing along the margin of the third eyelid. This portion of third eyelid was surgically excised, and histopathology identified the haired tissue as a dermoid. Chronic keratitis secondary to a third eyelid dermoid was diagnosed, and excision appeared curative at 6 months post-operative follow-up.
Cavens VJ, Gemensky-Metzler AJ, Wilkie DA, Weisbrode SE, Lehman AM.To describe the long-term histologic and intraocular pressure (IOP) lowering effects of diode laser transscleral cyclophotocoagulation (TSCP) on the normal equine eye. Methods: Eight normal adult horses. Methods: TSCP was performed in one randomly assigned eye. Sixty spots were treated at settings of 1500 ms and 1500 mW. Two horses were randomly selected for euthanasia at 2, 4, 12, or 24 weeks post-TSCP. Both eyes were enucleated and histologically evaluated. Intraocular pressure was measured by applanation tonometry prior to TSCP, immediately post-TSCP, twice daily for 7 days post-TSCP and th...
Holve DL.To determine the effect of sedation with detomidine on intraocular pressure (IOP) in standing horses and whether topical ocular application of anesthetic alters this effect. Methods: Clinical trial. Methods: 15 clinically normal horses. Methods: Horses were assigned to group 1 (n = 7) or 2 (8). Intraocular pressure measurements were obtained at baseline (before sedation) and 10 minutes after IV administration of detomidine (0.02 mg/kg [0.009 mg/lb]). Group 1 horses had an additional IOP measurement at 20 minutes after sedation. For group 2 horses, topical ocular anesthetic was administered 10 ...
Evans PM, Armour MD, Dubielzig RR. To describe the gross and histopathological ocular findings in a horse following suspected lightning injury. Methods: The eyes of a 2-year-old thoroughbred gelding were clinically and histopathologically evaluated following a severe lightning storm following euthanasia because of visual impairment. Results: Severe corneal edema and hydrops were noted clinically oculus dexter. Indirect ophthalmoscopy revealed bilateral symmetrical raised hyporeflective peripapillary geographic lesions. Histopathologic evaluation revealed corneal edema in the right eye with normal corneal endothelium...
Irby NL.A complete neuro-ophthalmologic assessment is relatively simple, requires minimal instrumentation and should be performed as part of every complete ophthalmic and neurologic examination. This article has summarized the tests that comprise and the species-specific details of the complete neuro-ophthalmologic of the equine patient. Selected causes of sudden blindness in the horse were summarized and some common neuro-ophthalmic conditions with significant ophthalmic consequences, such as facial nerve paralysis, were discussed. Split-lid tarsorrhaphies, which are indicated but rarely used in case...
Pirie CG, Pizzirani S. To describe a novel digital single lens reflex (dSLR) camera adaptor for anterior and posterior segment photography. Methods: The adaptor was used to evaluate canine, feline, and equine patients presenting to Tufts Ophthalmology service. Anterior segment imaging was conducted with the adaptor mounted between a dSLR camera body (Canon 7D) and a macro lens (Canon EF-S 60mm/f2.8). Posterior segment imaging was performed with the aid of an indirect ophthalmic lens mounted in front of the macro lens. Coaxial illumination during viewing was provided by a single white light-emitting diode (LE...
Mathes RL, Burdette EL, Moore PA, Myrna KE.To report concurrent clinical intraocular findings in horses with depigmented punctate chorioretinal foci and to document any correlation with equine recurrent uveitis (ERU). Methods: Records of 131 horses (241 eyes) examined at the University of Georgia Veterinary Teaching hospital from 2001 to 2010 were reviewed with either clinically normal fundi or depigmented punctate chorioretinal foci in the absence of other fundic pathology. Data collected included patient signalment, concurrent clinical ocular findings and follow-up information. Sex, presence of no other intraocular findings, presence...
de Sousa ME, Araújo MA, Mota RA, Porto WJ, Souza AK, Dos Santos JL, da Silva PP.Normal fungal conjunctiva microbiota of horses remains stable in healthy animals, free from ocular and/or systemic diseases which may, eventually, cause ocular alterations. The knowledge of the fungal microbiota is of great importance due to the reduced number of studies reported in the literature and also to the large occurrence of ocular alterations, mainly keratomycosis, in these animals. The aim of this study was to isolate and to identify the fungi present in the ocular conjunctiva of healthy horses belonging to the Military Police Cavalry of Alagoas. Samples from both conjunctival sacks ...
Curling A.Equine recurrent uveitis has traditionally been treated with medical management to reduce ocular inflammation and control pain during a single episode. Newer management methods include surgical options such as cyclosporine implantation and vitrectomy. These methods were developed not only to control inflammation but also to eliminate the underlying cause of uveitis in order to prevent recurrence.
Curling A.Equine recurrent uveitis is a cyclical disease that affects the eye and often leads to high management costs and unfavorable results, such as blindness. Research has improved understanding of the roles of various etiologies, especially leptospirosis, in initiating and perpetuating the pathogenesis of equine recurrent uveitis. Research has also led to the discovery that specific breeds and horses with specific coat color patterns may be predisposed to developing recurrent uveitis.
Labelle AL, Hamor RE, Townsend WM, Mitchell MA, Zarfoss MK, Breaux CB, Thomasy SM, Hall T.To determine types and frequency of ophthalmic lesions detected in neonatal foals evaluated for nonophthalmic disease at 3 veterinary referral hospitals and to investigate associations between systemic and ophthalmic diseases in these foals. Methods: Prospective cross-sectional study. Methods: 70 foals < 30 days old. Methods: Complete ophthalmic examinations were performed. Signalment, clinical signs, mentation during ophthalmic examination, results of clinicopathologic tests, and diagnosis of systemic disease were recorded. Descriptive data analysis including a χ(2) test for associations was...
Marfe G, Massaro-Giordano M, Ranalli M, Cozzoli E, Di Stefano C, Malafoglia V, Polettini M, Gambacurta A.Stem cell technology has evoked considerable excitement among people interested in the welfare of animals, as it has suggested the potential availability of new tools for several pathologies, including eye disease, which in many cases is considered incurable. One such example is ulcerative keratitis, which is very frequent in horses. Because some of these corneal ulcers can be very severe, progress rapidly and, therefore, can be a possible cause of vision loss, it is important to diagnose them at an early stage and administer an appropriate treatment, which can be medical, surgical, or a combi...
Hilton HG, Magdesian KG, Groth AD, Knych H, Stanley SD, Hollingsworth SR.Nonsteroidal anti-inflammatory drugs (NSAIDs) are commonly used systemically for the treatment of inflammatory ocular disease in horses. However, little information exists regarding the ocular penetration of this class of drugs in the horse. Objective: To determine the distribution of orally administered flunixin meglumine and firocoxib into the aqueous humor of horses. Methods: Fifteen healthy adult horses with no evidence of ophthalmic disease. Methods: Horses were randomly assigned to a control group and 2 treatment groups of equal sizes (n = 5). Horses assigned to the treatment groups rece...
Townsend WM, Jacobi S, Bartoe JT.Presently, intraocular lenses (IOLs) are not routinely implanted after equine cataract surgery. Subsequently, horses are visual but markedly farsighted (hyperopic). This report describes the surgical results and visual status after phacoemulsification and implantation of IOLs in mature horses with spontaneous cataracts. Six eyes of 5 mature horses underwent phacoemulsification and implantation of a +14 diopter (D) foldable IOL. Recheck ocular examinations were performed at 1, 4 and 24 weeks post operatively. Refractive error was recorded at 4 weeks post operatively. Visual status, refractive e...
Andersson LS, Axelsson J, Dubielzig RR, Lindgren G, Ekesten B.Multiple congenital ocular anomalies (MCOA) syndrome is a hereditary congenital eye defect that was first described in Silver colored Rocky Mountain horses. The mutation causing this disease is located within a defined chromosomal interval, which also contains the gene and mutation that is associated with the Silver coat color (PMEL17, exon 11). Horses that are homozygous for the disease-causing allele have multiple defects (MCOA-phenotype), whilst the heterozygous horses predominantly have cysts of the iris, ciliary body or retina (Cyst-phenotype). It has been argued that these ocular defects...
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, ...
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 ...
Wada S, Ode H, Hobo S, Niwa H, Katayama Y, Takatori K.To describe a case of superficial keratomycosis caused by Mortierella wolfii (M. wolfii) in a horse. Methods: A thoroughbred filly was presented with painful right eye of 2 days' duration. A superficial corneal ulcer was observed ventrally together with multifocal punctuate opacities axially. Samples were collected by swabbing and scraping the ulcerated lesion and submitted for microbiologic and cytologic examination. Results: Microscopic evaluation of debrided corneal tissue revealed the presence of nonseptate fungal hyphae, and culture of a corneal swab yielded fungal growth. Medical treat...
Sandmeyer LS, Bellone RR, Archer S, Bauer BS, Nelson J, Forsyth G, Grahn BH. To determine if congenital stationary night blindness (CSNB) exists in the Miniature Horse in association with leopard complex spotting patterns (LP), and to investigate if CSNB in the Miniature Horse is associated with three single nucleotide polymorphisms (SNPs) in the region of TRPM1 that are highly associated with CSNB and LP in Appaloosas. Methods: Three groups of Miniature Horses were studied based on coat patterns suggestive of LP/LP (n=3), LP/lp (n=4), and lp/lp genotype (n=4). Methods: Horses were categorized based on phenotype as well as pedigree analysis as LP/LP, LP/lp,...
Smith PJ, Gum GG, Whitley RD, Samuelson DA, Brooks DE, Garcia-Sanchez GA.Tonometric and tonographic techniques were evaluated in the normal pony and compared to other species. Applanation tonometry was utilised to calculate the ocular ridigity of the normal equine eye. The mean intraocular pressure for the pony eye was established as 23.5 mm Hg (sd +/- 4.5). Comparing the non-anaesthetised and anaesthetised pony eye (xylazine-ketamine and glycerol guaiacolate) no significant change in intraocular pressure occurred (P < 0.49). Mean aqueous outflow facility was 0.88 microliter/min/mm Hg (sd +/- 0.65) which is significantly higher (P < 0.01) than the canine and ...
Matthews AG, Crispin SM, Parker J.A wide range of fundic variants are encountered during routine ophthalmoscopic examination of visually normal horses, often causing the examiner difficulty in assessing their clinical significance. Many of these are anatomical variants having no significant effect on visual function, and lie within the limits of normality in the horse. This paper illustrates this range of variants and discusses their anatomical basis and physiological consequences. Colobomata are non-progressive discontinuities in the structure of the anatomic fundus, occasionally noted as incidental findings during ophthalmos...
Sanchez S, Studer M, Currin P, Barlett P, Bounous D.Listeria monocytogenes is ubiquitous in the environment but is rarely reported as a cause of keratitis in animals. In this case, a mare was presented with epiphora and evidence of pain in the right eye. Listeria monocytogenes was isolated from a corneal lesion, and bacteria were also seen in the cytologic evaluation. This is the first reported case of ulcerative keratitis associated with L. monocytogenes in a horse.
Proietto L, Beatty SS, Plummer CE.To compare corneal cytology samples from three common sampling techniques: cytobrush (CB), Kimura platinum spatula (KS), and the handle edge of a scalpel blade (SB). Methods: Equine patients presenting to the University of Florida College of Veterinary Medicine with ulcerative keratitis were included. Following diagnosis of corneal ulcer and sampling for microbial culture, two cytology samples per technique were collected with sterile CB, KS, and SB in a randomized order. Cytologic evaluation was performed by two observers masked to collection method. Objective measures of sample cellularity, ...
Neumann SM, Kainer RA, Severin GA.In the main study, hyperthermia was induced by radio-frequency current to obtain a single, central, corneal lesion in the right eye and 2 separate limbal lesions in the left eye of 13 light horses and 8 ponies. Intracorneal and intralimbal temperature profiles for the procedure were obtained in a separate study from the eyes of a horse and a pony treated in the same manner. After treatment of the principal eyes and 6 sham-treated eyes, clinical observations were conducted for up to 6 months, using indirect ophthalmoscopy, biomicroscopy, and fluorescein staining. Immediately after hyperthermic ...
Dziezyc J, Millichamp NJ, Keller CB.The medical records of 12 horses that had cataracts removed by use of phacofragmentation were reviewed. Cataracts were removed from 16 eyes in horses ranging in age from 2 months to 15 years. Complications after surgery included corneal ulcers in 13 eyes, diffuse corneal edema in 5 eyes, and uncontrollable uveitis in 3 eyes. Follow-up information was obtained in all horses from 1 month to 3.5 years after surgery. Visual results were judged good by owners or veterinarians in 10 of the horses.
Marolt J, Naglić T, Hajsig D.A case of a spontaneous mycokeratitis of a previously injured cornea in a horse is described. The infection was caused by Aspergillus oryzae. After application of Chloramphenicol ophthalmic ointment a corneal clouding was found in the centre which was circularly sharply defined and which - after dispensing Dexamethason-Neomycin eye drops - expanded all over to a purulent keratitis. The demarcated and initially non purulent mycotic lesions largely improved after the application of tincture of iodine, whereas the purulent keratitis could be completely cured only by a lasting treatment with Lugol...
Scherrer NM, Lassaline-Utter M, McKenna BC.To determine the histologic findings associated with masses in the nictitating membranes (third eyelids) of horses and to identify prognostic factors associated with recurrence and the outcome. Methods: Retrospective case series. Methods: 50 horses with masses in a third eyelid. Methods: Medical records of horses with partial or complete excision of a third eyelid and submission for histologic evaluation between September 1998 and November 2012 were reviewed. Horses were included if follow-up information for at least 1 year after surgery was available. Information regarding signalment and trea...
de Sousa ME, Araújo MA, Mota RA, Porto WJ, Souza AK, Dos Santos JL, da Silva PP.Normal fungal conjunctiva microbiota of horses remains stable in healthy animals, free from ocular and/or systemic diseases which may, eventually, cause ocular alterations. The knowledge of the fungal microbiota is of great importance due to the reduced number of studies reported in the literature and also to the large occurrence of ocular alterations, mainly keratomycosis, in these animals. The aim of this study was to isolate and to identify the fungi present in the ocular conjunctiva of healthy horses belonging to the Military Police Cavalry of Alagoas. Samples from both conjunctival sacks ...
Neaderland MH, Riis RC, Rebhun WC, Erb HN.Corneal ulcers to the depth of the anterior third of the stroma were created surgically in both eyes of 10 ponies. One eye in each pony was treated topically with chloramphenicol and 1% atropine ophthalmic ointments 3 times per day; the contralateral eye was not treated topically. All ponies were given phenylbutazone orally for relief of ocular pain. Fluorescein-stained ulcers were measured once a day. The median healing time of the treated eyes (11 days) and the median healing time of the nontreated eyes (13.5 days) were found not to be significantly different. Clinically, however, more sever...
McLellan GL, Archer FJ.A 19-year-old Shetland pony presented with unilateral ocular discomfort and abnormal ocular appearance. Keratoconjunctivitis sicca, ulcerative keratitis and brown discoloration of the corneal stroma were identified on ophthalmic examination. The etiology of keratoconjunctivitis sicca was not determined in this case. For practical and financial reasons, the owners requested enucleation of the affected eye. Histopathologic examination revealed extensive loss of corneal epithelium overlying a zone of hypereosinophilic, degenerate, and necrotic corneal stroma. This well-circumscribed region of cor...
Davidson HJ, Pinard CL, Keil SM, Brightman AH, Sargeant JM.The ocular effects of latanoprost ophthalmic solution were evaluated in two studies, with eight horses in each study. One eye of each horse was treated with latanoprost ophthalmic solution once daily for 5 days, and the opposite eye received a control solution of sterile eyewash. Intraocular pressure and pupillary diameter were measured daily for 5 days after treatment. Latanoprost had no significant effect on intraocular pressure or pupillary diameter in normal horse eyes compared with control eyes in these studies. Placement of an eyelid nerve block resulted in significantly lower intraocula...
Rendle DI, Hughes KJ.Intracameral injection of tissue plasminogen activator has been suggested as a means of hastening the clearance of blood from the anterior chamber and reducing the risk of synechia and fibrotic membrane formation in horses with hyphaema. The following report describes a case of ocular trauma in which intracameral injection of tenecteplase (TNK), a new-generation plasminogen activator, resulted in rapid resolution of hyphaema and successful outcome. However, a large dose (1 mg) was administered and may have been associated with retinopathy and keratopathy. TNK may be an effective treatment for ...
Hamor RE, Roberts SM, Severin GA, Trawnik WR, Johnson WJ.Specific details on surgical procedures, although not covered here, are available in other references. Factors enhancing the overall cosmetic appearance obtained with procedures are emphasized, providing information that should allow veterinarians to offer clients a good cosmetic appearance and effective treatment for disfiguring ocular problems in their horses. Questions regarding procedures should be addressed to your referral ophthalmologist or, in the case of a corneoscleral prosthesis, the ocularist assisting.
Mettenleiter EM.In this presentation, normal sonoanatomy of the horse eye will be introduced and biometrical data of 30 healthy eyes along optical axis will be presented. We used the ultrasound system Philips Diagnost R 1200 in connection with a 5 MHz linear transducer. With this equipment it is possible to visualize and measure at the unaltered eye the cornea, the anterior chamber of the eye, ciliary body, iris, lens, vitreous body, wall of the posterior globe (retina, choroid, sclera) and retrobulbar structures (optical nerve, retrobulbar muscles, orbital fat pad, bony orbita). The echographical examination...
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.
Faghihi H, Rajaei SM, Mehrazin H, Golabdar S, Brooks DE.The aim of this study was to evaluate the effect of topical 1% tetracaine hydrochloride on the intraocular pressure (IOP) in ophthalmologically normal horses. Thirty eyes of 15 clinically normal horses were used for this study. The animals were randomly assigned to two groups (treatment and control). Prior to the instillation of 1% tetracaine or placebo, the baseline IOPs (T0) of each animal were recorded in both groups. Then one drop of tetracaine was instilled randomly into one eye of each horse in the treatment group (8 horses). In the control group (7 horses), one drop of artificial tear w...
Arenas-Gamboa AM, Mansell J.Haemangiosarcomas (HSAs) are malignant tumours of endothelial cell origin. Epithelioid HSA is a variant of the histologically conventional HSA that has little or no morphological evidence of a vascular origin and has been reported rarely in domestic animals. The following report documents six cases of equine epithelioid HSA occurring in the ocular tissues of horses with a mean age of 19.8 years at the time of diagnosis. Microscopically, all of the lesions consisted of solid sheets or cords of epithelioid cells with rare narrow clefts or small spaces containing erythrocytes that were often the ...
Hisey EA, Martins BC, Donnelly CG, Cassano JM, Katzman SA, Murphy CJ, Thomasy SM, Leonard BC.This study aimed to define the antimicrobial peptide (AMP) expression pattern of the equine ocular surface and amniotic membrane using a targeted qPCR approach and 3'Tag-sequencing. It will serve as a reference for future studies of ocular surface innate immunity and amniotic membrane therapies. Methods: A targeted qPCR approach was used to investigate the presence of orthologs for three of the most highly expressed beta-defensins (DEFB1, DEFB4B, and DEFB103A) of the human ocular surface and amniotic membrane in equine corneal epithelium, conjunctiva, and amniotic membrane. 3'Tag-sequencing wa...
Ramsey DT, Whiteley HE, Gerding PA, Valdez RA.An 11-year-old Quarter Horse gelding was evaluated because of a persistent, raised band of 1- to 2-mm subepithelial plaques of the left cornea. Cytologic examination of corneal scrapings revealed numerous eosinophils and segmented neutrophils, with few mast cells, plasma cells, and lymphocytes. Bacteriologic culture yielded sparse growth of alpha-hemolytic Streptococcus and Staphylococcus spp. Histologically, the plaques consisted of subepithelial foci of fragmented and degenerated collagen fibers infiltrated by eosinophils and neutrophils, with few lymphocytes, plasma cells, and macrophages. ...
Chandler KJ, Billson FM, Mellor DJ.Ophthalmic lesions were detected in 67 of 83 horses and ponies aged 15 years or more. Degeneration of the vitreous, followed by senile retinopathy, were the most common lesions and both of them became more common with advancing age, although few of the owners reported disturbances of vision in their animals.
Leigh H, Gozalo-Marcilla M, Esteve V, Gutiérrez Bautista ÁJ, Martin Gimenez T, Viscasillas J.Standing surgery in horses combining intravenous sedatives, analgesics and local anaesthesia is becoming more popular. Ultrasound guided (USG) peribulbar nerve block (PB) has been described in dogs and humans for facial and ocular surgery, reducing the risk of complications versus retrobulbar nerve block (RB). Objective: To describe a technique for USG PB in horse cadavers. Methods: Landmarks and PB technique were described in two equine cadaver heads (Phase 1), with computed tomography (CT) imaging confirming contrast location and spread. In Phase 2, ten equine cadaver heads were randomised t...
Hacker DV, Moore PF, Buyukmihci NC.In 4 horses with ocular angiosarcomas, the common characteristics were that all horses were aged, and the neoplasms developed initially on conjunctival surfaces, grew slowly, and metastasized despite excision and radiation treatment. Histopathologically, the neoplasms were of 2 types: a capillary pattern of scant stroma and endothelial-lined vascular channels, and a solid pattern composed of sheets of pleomorphic cells with hyperchromatic nuclei and poorly defined cytoplasmic borders. Definitive diagnosis was made by use of factor VIII:RAg, which stained the tissues intensely.
Turner AG.A discussion of ocular conditions of foals with an emphasis on congenital and inherited disorders is presented. An understanding of the normal postnatal development of the eye and adnexae is important. Recognition of inherited abnormalities is essential when giving advice on breeding suitability, and prompt attention or referral of deteriorating ocular conditions in foals ensures the best outcome for future use. Congenital conditions may be recognized for the first time in older animals during their first thorough eye examination.
Brünott A, Boevé MH, Velden MA.To describe the clinical symptoms of 10 cases of superficial nonhealing corneal ulcers in horses and to evaluate the results of grid keratotomy in these patients. Methods: Retrospective study. Methods: Ten horses with superficial nonhealing corneal ulceration in one eye. Methods: The signalment, history and clinical symptoms are reported of 10 patients with superficial nonhealing corneal ulcers during the period from August 2003 to February 2005. Grid keratotomy was performed in all cases. In addition, the surgical procedure of grid keratotomy and response to therapy are described. Results: Ho...
Rebhun WC.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.
Yamagata M, Wilkie DA, Gilger BC.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...
Westermeyer HD, Hendrix DV, Ward DA, Cox SK.To determine ocular tissue drug concentrations after topical ocular administration of 0.3% ciprofloxacin and 0.5% moxifloxacin in ophthalmologically normal horses. Methods: 24 ophthalmologically normal adult horses. Methods: 0.3% ciprofloxacin and 0.5% moxifloxacin solutions (0.1 mL) were applied to the ventral conjunctival fornix of 1 eye in each horse as follows: group 1 (n = 8) at 0, 2, 4, and 6 hours; group 2 (8) at 0, 2, 4, 6, and 10 hours; and group 3 (8) at 0, 2, 4, 6, 10, and 14 hours. Tears, cornea, and aqueous humor (AH) were collected at 8, 14, and 18 hours for groups 1, 2, and 3, r...
Meister U, Görig C, Murphy CJ, Haan H, Ohnesorge B, Boevé MH.Phacoemulsification and intraocular lens (IOL) implantation during cataract surgery in horses occur with increasing frequency. To reduce the postoperative refractive error it is necessary to determine the proper IOL power. In the present study retinoscopy, keratometry and ultrasonographic biometry were performed on 98 healthy equine eyes from 49 horses. The refractive state, corneal curvature (keratometry) and the axial location of all optical interfaces (biometry) were measured. The influences of breed, height at the withers, gender and age on values obtained and the comparison between the le...
