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.
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...
Komáromy AM, Andrew SE, Sapp HL, Brooks DE, Dawson WW.The goal of our study was the evaluation of a practical method for the recording of flash electroretinograms (ERGs) in sedated, standing horses with the DTL microfiber electrode. Methods: The horses were sedated intravenously with detomidine hydrochloride (0.015 mg/kg). The pupil was dilated and the auriculopalpebral nerve was blocked. The ERGs were recorded with the active electrode on the cornea (DTL), the reference electrode near the lateral canthus, and the ground electrode over the occipital bone. The light intensities of the white strobe light were 0.03 cd x s/m2 (scotopic) and 3 cd x s/...
Cutler TJ.Ophthalmic conditions of the older horse are becoming increasingly common as geriatric care advances. The close relation between the eye and other structures of the head exposes the globe to direct expansion of clinical disease and raises management issues. Integrating an ophthalmic and fundic examination into the annual evaluation should reward the investment, permit enhanced patient care, and potentially provide early identification of systemic conditions. Surgical and medical management of neoplastic conditions is most successful with early identification and therapy. It is hoped that this ...
Storey ES, Gerding PA, Scherba G, Schaeffer DJ.To determine survival over time of infectious equine herpesvirus-4, feline herpesvirus-1, and feline calicivirus in three commercially available and commonly used ophthalmic solutions (eyewash, fluorescein, and proparacaine HCl). Methods: Viruses used in this study were originally isolated from eyes of animals referred to the University of Illinois. Equine herpesvirus-4 was propagated in MDBK cells and feline herpesvirus-1 and feline calicivirus in CRFK cells. Methods: After separately inoculating a designated solution with a specific titer of an individual virus, solutions were incubated per ...
Kingston JK, Bayly WM, Sellon DC, Meyers KM, Wardrop KJ.To investigate the effects of formaldehyde fixation on equine platelets using flow cytometric methods to evaluate markers of platelet activation. Methods: Blood samples from 6 Thoroughbreds. Methods: The degree of fluorescence associated with binding of fluorescein isothiocyanate (FITC)-conjugated anti-human fibrinogen antibody and FITC-annexin V in unactivated and adenosine diphosphate (ADP)-, platelet activating factor (PAF)-, and A23187-activated platelet samples in unfixed and 0.5, 1.0, and 2.0% formaldehyde-fixed samples was assessed by use of flow cytometry. Results: In samples incubated...
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...
Ehrenhofer MC, Deeg CA, Reese S, Liebich HG, Stangassinger M, Kaspers B.Investigations of the pathophysiology of ocular diseases require a detailed knowledge of the microanatomy of the eye. The available information is still inadequate for the equine retina despite the importance of eye diseases in equine medicine. Here we provide a comprehensive analysis of the histologic features of the horse eye as a reference for future studies. Thirty normal eyes of 15 healthy horses were examined immediately after slaughter. The retina of the horse differs considerably in the degree and quantity of neurons and glial elements as well as in vascular patterns compared to the re...
Beard WL, Wilkie DA.Ocular and periorbital sarcoids and squamous cell carcinoma are common in equine practice. Extensive involvement of periorbital tissues often necessitates removal of the globe if the function of the eyelids can not be maintained with tumor removal alone. This report describes a modification of the standard enucleation or exenteration technique for cases in which there is insufficient skin to achieve primary closure following complete surgical excision. The caudal portion of the dorsal orbital rim is protuberant; partial excision with an osteotome facilitates skin closure by decreasing the size...
Gilger BC, Wilkie DA, Davidson MG, Allen JB.To evaluate the use of an intravitreal sustained-release cyclosporine (CsA) delivery device for treatment of horses with naturally occurring recurrent uveitis. Methods: 16 horses with recurrent uveitis. Methods: Horses with frequent recurrent episodes of uveitis or with disease that was progressing despite appropriate medication were selected for this study. Additional inclusion criteria included adequate retinal function as determined by use of electroretinography, lack of severe cataract formation, and no vision-threatening ocular complications (eg, retinal detachment, severe retinal degener...
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.
Miller TL, Willis AM, Wilkie DA, Hoshaw-Woodard S, Stanley JR.To determine the most appropriate anatomical location for diode laser probe placement to accurately photoablate the equine ciliary body using a contact, transscleral approach. Methods: Original research. Methods: Forty-two freshly enucleated adult equine eyes were evaluated. The horizontal, medial vertical, central vertical, and lateral vertical lengths of the cornea were measured from limbus to limbus. Needles were inserted perpendicular to the sclera at specific distances posterior to the external limbus at the 1, 2, 4, 5, 6, 7, 8, 10, 11 and 12 o'clock positions. The per cent frequency that...
Hardman C, McIlnay TR, Dugan SJ.A 3-year-old Paint gelding was presented for sudden onset of cataract affecting the right eye. Ophthalmic examination revealed subtle to mild microphthalmia and a mature cataract affecting the right globe. The right eye was treated with an antibiotic-corticosteroid ophthalmic ointment and phacofragmentation was recommended. On re-examination 5 months later, resorption of the cortex of the right lens and a morgagnian cataract were evident. The nucleus was positioned ventronasally in the lens capsule. The right eye had light perception, and a menace response was present. Examination of the right...
Kershaw O, von Oppen T, Glitz F, Deegen E, Ludwig H, Borchers K.The prevalence of EHV-2 in 27 horses with keratoconjunctivitis and 21 clinically healthy horses of different ages and stocks were analyzed. We demonstrated that EHV-2 was present in 12 keratoconjunctivitis cases as shown by nested PCR on ocular swabs. This is statistically more often than in the control group, where only two ocular swabs were EHV-2 positive. Cocultivation was successful on peripheral blood leukocytes of healthy and diseased horses but not on swabs. We isolated ten EHV-2 strains from diseased and nine from control horses, whereas 16 isolates showed different restriction enzyme ...
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...
Fleming PR, Crompton JL, Simpson DA.The aim of this study was to highlight the neuro-ophthalmological dangers associated with horse riding, and working around horses, and the importance of wearing adequate headgear to protect the rider from neuro-ophthalmic injuries. It raises the questions of whether the current laws regarding helmet use are satisfactory, and whether helmets currently used are of an adequate standard. Methods: The records over a 20-year period of one neuro-ophthalmologist in Adelaide were reviewed producing 22 patients with neuro-ophthalmological sequelae of head injuries as a result of horse-related accidents....
Moore CP, Grevan VL, Champagne ES, Collins BK, Collier LL.Five horses presented with unilateral pink, smooth, nonulcerated conjunctival masses with histologic features characteristic of inflammatory pseudotumors, i.e. proliferative inflammatory lesions clinically resembling true neoplasia. Although causes for the inflammatory lesions were not determined, based on the presence histologically of mononuclear (predominantly lymphocytic) inflammatory cell infiltrates and the absence of infectious agents, parasites or foreign bodies, an immune-mediated pathogenesis was suspected. Affected horses ranged from 5 to 8 years of age with no apparent breed or sex...
Herring IP, Pickett JP, Champagne ES, Troy GC, Marini M.OBJECTIVE: To determine the effect of topical 1% ophthalmic atropine sulfate on intraocular pressure (IOP) in ocular normotensive horses. Animals Studied Eleven clinically healthy horses. Procedures IOP was measured bilaterally twice daily, at 8 AM and 4 PM, for 5 days. No medication was applied for the first 2 days of the study. Thereafter, one eye of each horse was treated with 0.1 mL of topical 1% atropine sulfate ointment twice daily (7 AM and 7 PM) for 3 days. The contralateral eye served as a control. In eight of the horses, an additional IOP reading was taken 3 days following cessation ...
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...
Crispin SM.The iris is derived from interaction between neural crest tissue and the adjacent neuroectoderm of the optic cup. Developmental anomalies of the equine iris are common, and include congenital miosis, iris cysts, various manifestations of iris hypoplasia, heterochromia, and persistent pupillary membrane remnants. They may be found alone or in combination with other ocular defects.
Brooks DE, Andrew SE, Denis H, Strubbe DT, Biros DJ, Cutler TJ, Samuelson DA, Gelatt KN.Purpose To describe the clinical appearance of corneal epithelial cell microerosions associated with keratomycosis in the horse. METHODS: Retrospective clinical study. RESULTS: Multifocal, punctate, superficial corneal opacities with positive rose bengal retention were noted in six horses with presumed 'viral keratitis'. Faint fluorescein staining was also present in three cases. Equine herpesvirus tissue culture inoculation was negative for a cytopathic effect in three cases. Aspergillus (n = 3), Curvularia (n = 1), and an unidentified fungus (n = 1) were cultured in five horses, and hyphae f...
Gilger BC, Malok E, Stewart T, Ashton P, Smith T, Jaffe GJ, Allen JB.OBJECTIVE: To determine the long-term toxicity of an intravitreal device releasing continuous cyclosporinee A (CsA) in normal eyes of horses by evaluating clinical signs, electroretinography, and histopathology. Animals Studied Ten adult horses with normal ophthalmic examinations were used in this study Procedure(s) Four horses had one eye implanted with a CsA device, and six horses had the right eye implanted with a CsA-containing device (10 eyes with CsA in total) and the left eye (six eyes in total) with the device without drug (control). The implants were placed in the vitreous of the eyes...
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...
Williams MM, Spiess BM, Pascoe PJ, O'Grady M.OBJECTIVE: To identify any systemic effects of topical and subconjunctival administration of atropine sulfate in the horse. Animals studied Six mature grade horses were treated hourly in one eye with topical ophthalmic atropine drops for 24 h. Five horses were treated subconjunctivally in one eye with 3 mg of atropine sulfate. Procedures Pupillary light reflexes, pupil size, electrocardiographic parameters, girth measurements, intestinal motility, and clinical signs of abdominal pain were monitored. RESULTS: Alteration in auscultated gut motility and clinical signs of abdominal pain were the m...
Crispin SM.Tear-deficient dry eye (keratoconjunctivitis sicca), and evaporative dry eye, with some overlap between these two categories, are two major categories of dry eye recognized in the horse. Careful examination of the eyelid margins, the inner and outer surfaces of the upper and lower eyelids, assessment of blink and third eyelid movement, specific testing of tear production, assessment of corneal sensitivity, and slit-lamp examination of the ocular surface before and after fluorescein dye application is recommended to detect dry eye problems. Rose Bengal dye application is also recommended in man...
Brooks DE, Andrew SE, Biros DJ, Denis HM, Cutler TJ, Strubbe DT, Gelatt KN.Purpose To describe 11 clinical cases of ulcerative keratitis in horses associated with beta-hemolytic Streptococcus equi in Florida, USA. METHODS: Retrospective clinical study (1996-99). RESULTS: Beta-hemolytic Streptococcus equi was cultured from 11 horses with deep ulcers, descemetoceles or iris prolapse (n = 8), a suture abscess found with a penetrating keratoplasty for a stromal abscess (n = 1), and ulceration that developed following keratectomy/irradiation for corneal squamous cell carcinoma (n = 2). Beta-hemolytic Streptococcus equi subspecies zooepidemicus was found in 10 eyes and sub...
Whigham HM, Brooks DE, Andrew SE, Gelatt KN, Strubbe DT, Biros DJ.Contact neodymium:yttrium aluminum garnet (Nd:YAG) laser transscleral cyclophotocoagulation (TSCP) was performed on 23 eyes of 16 horses for treatment of glaucoma. The mean highest preoperative IOP was 51 +/- 17 mmHg. Follow-up evaluation was available for 19 eyes 1 day after surgery, 14 eyes from 1 to 2 weeks, 16 eyes from 4 to 6 weeks, 9 eyes from 12 to 16 weeks, and 10 eyes greater than 20 weeks after laser treatment. The mean intraocular pressure (IOP) the day following surgery was 34 +/- 13 mmHg. The mean IOP for each follow-up period was: one to two weeks postoperative, 23 +/- 9 mmHg; fo...
Giuliano EA, Maggs DJ, Moore CP, Boland LA, Champagne ES, Galle LE.The objective of this study was to describe method of placement, and frequency and severity of complications associated with a subpalpebral lavage system placed in the medial aspect of the equine inferior eyelid. The inferomedial subpalpebral lavage (ISPL) tube is positioned deep in the medial aspect of the inferior conjunctival fornix so that the footplate lies flat between the lower eyelid and the anterior surface of the nictitans. Retrospective data from the placement of 92 ISPL systems placed in 86 horses during a 31-month period were examined. Tube placement was performed using sedation a...
Frühauf B, Ohnesorge B, Deegen E, Boevé M.Current information suggests that equine recurrent uveitis (ERU) is an immune-mediated reaction to infectious agents or to autologous ophthalmic tissue. Recurrences are associated with progression of irreversible ocular damage. This report describes the intraoperative technique, complications, and long-term results of 38 eyes in 35 horses with ERU that underwent pars plana vitrectomy. The majority of the horses were warm-blooded. Recurrence of ERU was prevented in 35 of the 38 eyes. Some horses, especially in patients with incipient cataracts, developed vision loss in postoperative, quiescent ...
Gasthuys F, Pockelé K, Vervaet C, Weyenberg W, De Prijck K, Pille F, Vlaminck L, Nelis H, Remon JP.The in vivo behaviour of 5% gentamicin sulphate ocular mini-tablets (2-mm diameter, 6.525 mg weight) was compared with gentamicin eye drops in six ponies. Two mini-tablets were inserted on the bulbar conjunctiva of the right eye while a similar dose of gentamicin was administered via eye drops in the left eye. Irritation induced by the mini-tablets and the eye drops was evaluated using a visual analogue scale (0-10). Tears were sampled with ophthalmologic absorption triangles for 1 min for the determination of the concentration of gentamicin sulphate using a microbiological plate diffusion met...
Makra Z, Csereklye N, Riera MM, McMullen RJ, Veres-Nyéki K.In this controlled, blinded, randomized block pilot study, the main objective was to evaluate the effectiveness of intravenous flunixin meglumine, phenylbutazone, and acupuncture on ocular pain relief using a multifactorial pain scale in the horse. Four experimental horses underwent corneal epithelial debridement in four sessions, when a randomly selected treatment or a control was used. All horses were pain scored before corneal wounding, then at 18 time points, when 11 parameters were allocated. Differences in the area under the curve of pain scores between the treatment groups were analyzed...
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...
Bessonnat A, Vanore M.Evaluate the effect of repeated doses of topical 1% cyclopentolate hydrochloride alone and in combination with topical 2.5% phenylephrine on pupil diameter (PD), tear production (STT-1), intraocular pressure (IOP), digestive function (gut motility and feces production), and heart rate (HR). Methods: Six healthy mares. Methods: In a prospective, randomized, controlled, and crossover design study, the left eye of six healthy mares was administered 0.2 mL of cyclopentolate alone and in combination with 0.2 mL of phenylephrine. The drugs were administered 3 times a day for 1 day, twice a day fo...
Himebaugh NE, Robertson JB, Weninger K, Gilger BC, Ekesten B, Oh A.The aim of this study was to assess the transmission of the ultraviolet (UV) radiation (200-400 nm) through intact enucleated globes of different species (dogs, cats, pigs, rabbits, horses, and humans) using spectrophotometry. Globes of cats (n = 6), dogs (n = 18), pigs (n = 10), rabbits (n = 6), horses (n = 10), and humans (n = 4) were analyzed. A 5-10 mm circular area of sclera and choroid from the posterior aspect of the globe was removed under a surgical microscope, leaving the retina intact in all species except the horse. Glass coverslips were added in horses and rabbits du...
Gemensky-Metzler AJ, Wilkie DA, Weisbrode SE, Kuhn SE.To determine appropriate location and energy settings for trans-scleral cyclophotocoagulation (TSCPC) for buphthalmic equine globes. Methods: Eleven horses with a buphthalmic eye blinded by glaucoma presented for enucleation. Methods: Globe and corneal dimensions were measured via ultrasonography and calipers, and TSCPC was performed under general anesthesia immediately prior to enucleation. Part 1: In nine globes, sixty sites were lasered 4 mm posterior to the limbus in the dorsotemporal and ventrotemporal quadrants at settings of 1500 milliwatts and 1500 ms. Globes were processed and section...
Wafy MN, Hassan EA, El-Maaty AMA, Abu-Seida AM.Despite the extensive research on ocular ultrasonography, there is paucity of information regarding ocular biometry and color Doppler imaging of the donkey's eye. This study establishes B-scan ocular biometry and color Doppler ultrasonographic reference values in normal donkeys and describes effect of laterality, maturity and gender on ocular biometry and vasculature. Forty (80 eyes) clinically normal immature and mature donkeys of both sexes were included. Transpalpebral ocular ultrasonography was made using a 12-MHz linear transducer. Biometric ocular measurements were made including the ant...
Von Zup M, Lassaline M, Kass PH, Miller PE, Thomasy SM.Brimonidine is an α2 -adrenergic agonist that decreases aqueous humour production and may increase uveoscleral outflow. It has not been evaluated in normal or glaucomatous equine eyes. Objective: To evaluate the efficacy and safety of brimonidine in lowering intraocular pressure (IOP), alone and in conjunction with timolol, as a treatment for equine glaucoma by comparing IOP in normal equine eyes treated with brimonidine and brimonidine-timolol, respectively, with IOP in control eyes. Methods: A balanced crossover design with 16 horses receiving one of two treatments, brimonidine and brimonid...
Weinstein WL, Moore PA, Sanchez S, Dietrich UM, Wooley RE, Ritchie BW.To determine whether a novel third-generation chelating agent (8 mM disodium EDTA dehydrate and 20 mM 2-amino-2-hydroxymethyl-1, 3-propanediol) would act as an antimicrobial potentiator to enhance in vitro activity of antifungal medications against fungal isolates obtained from horses with mycotic keratitis. Methods: Fungal isolates (3 Aspergillus isolates, 5 Fusarium isolates, 1 Penicillium isolate, 1 Cladosporium isolate, and 1 Curvularia isolate) obtained from horses with mycotic keratitis and 2 quality-control strains obtained from the American Type Culture Collection (ATCC; Candida albica...
Giuliano EA, Maggs DJ, Moore CP, Boland LA, Champagne ES, Galle LE.The objective of this study was to describe method of placement, and frequency and severity of complications associated with a subpalpebral lavage system placed in the medial aspect of the equine inferior eyelid. The inferomedial subpalpebral lavage (ISPL) tube is positioned deep in the medial aspect of the inferior conjunctival fornix so that the footplate lies flat between the lower eyelid and the anterior surface of the nictitans. Retrospective data from the placement of 92 ISPL systems placed in 86 horses during a 31-month period were examined. Tube placement was performed using sedation a...
To evaluate the effect of four recumbent body positions on intraocular pressure (IOP) in anesthetized normal horses. Methods: Ten nonglaucomatous adult horses. Methods: Intraocular pressure was measured with a rebound tonometer in both eyes of standing sedated horses (baseline), then under general anesthesia during four randomized recumbent body positions, including Trendelenburg (Tr; 15-degree head down), reverse Trendelenburg (RTr; 15-degree head up), dorsal, and lateral; only the superior eye was measured in lateral positions. The mean of 3 IOP readings was taken at each position, allowing ...
Lamkin I, Pugliese B, Nystrom J, Fubini SL, Knickelbein KE.To describe the successful restoration of superior eyelid function in a horse following traumatic avulsion using an advancement flap blepharoplasty and subdermal hyaluronic acid filler. Methods: A 21-year-old American Paint Horse stallion who was attacked by a fellow stallion resulting in numerous traumatic injuries including avulsion of approximately 75% of the left superior eyelid. Methods: With standing sedation and locoregional anesthesia, the superior eyelid wound was debrided and an advancement flap blepharoplasty (H-plasty) and temporary tarsorrhaphy were performed. Routine healing of t...
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...
Plummer CE, Kallberg ME, Ollivier FJ, Barrie KP, Brooks DE.To describe and evaluate a surgical technique utilized for the therapy of deep corneal stromal abscesses (DSA) in horses. The DSA is excised and replaced with a partial thickness corneal lamellar allograft. Methods: A retrospective clinical study describing the indications for the surgical technique utilized and the outcomes of this procedure in 10 eyes of 10 horses. Results: Each affected eye had a discrete DSA within the posterior stroma. An initial partial thickness semicircular corneal incision was made at the limbus, followed by anterior stromal lamellar dissection over the lesion. After ...
Berzina I, Trumble NS, Novicki T, Sharkey LC.An 11-year-old American Saddlebred gelding was presented for evaluation of a nonpainful subconjunctival mass involving the lateral canthus of the left eye. Other findings included a central corneal scar and a small central cataract of the lens in the left eye. Fine-needle aspiration of the mass was performed and cytologic examination revealed marked pyogranulomatous inflammation with intralesional fungal hyphae, consistent with mycetoma. The fungal structures were elongated and characterized by nonstaining walls; several bulbous yeast-like structures were also observed. The mycetoma was surgic...
Van Der Woerdt A, Wilkie DA, Gilger BC, Strauch SM, Orczeck SM.OBJECTIVE: To determine the effect of single and multiple-dose 0.5% timolol maleate on intraocular pressure (IOP) and pupil size between 8 AM and 8 PM. Animals Nine female horses with normotensive eyes. Procedure IOP, horizontal and vertical pupil size were measured on a single day, between 8 AM and 8 PM at hours 0, 0.5, 1, 2, 4, 6, 8, 10, and 12. A single dose of 0.5% timolol maleate was applied to both eyes immediately after the first measurement at 8 AM. IOP and pupil size were measured at 8 AM and 4 PM in a 5-day experiment of twice-daily application of 0.5% timolol maleate. RESULTS: A sig...
Torres LEC, Florez CO, Oliveira JG, Vieira GD, Ribeiro IS, Keller KM, Leme FOP, Fantini P, Maranhão RPA.In equine ophthalmology, ulcerative keratitis is among the most common conditions and, in general, arises as a consequence of some trauma suffered. Secondarily, subsequent contamination by pathogenic or resident bacteria of the horse's ocular microbiota may have undesirable consequences. Under physiological conditions, the normal microbiota coexists with the immune status of the host, serving as a barrier, ensuring the health of the ocular surface, and inhibiting the proliferation of pathogens. However, in the imbalance of immune barriers, the normal microbiota can become pathogenic and lead t...
Ström L, Michanek M, Ekesten B.To investigate age-associated changes of flash visual evoked potentials (FVEPs) in sedated horses. Methods: Twenty-eight clinically healthy Standardbred Warmblooded trotters, aged 36 hours to 28 years. Methods: Light-adapted FVEPs and FERGs were recorded (An-vision RETIport, Roland-consult, Germany) in response to flash stimuli. Sedation was obtained using alpha-2-agonists intravenously. Akinesia of the eyelids was induced and pupils were dilated. Results: Reproducible FVEPs and FERGs were readily recorded from all foals and horses. The FVEP waveform included up to four positive components (...
Molleda JM, Cervantes I, Galán A, Tardón R, Gallardo JM, Martín-Suárez EM.To describe the protocol and appearance of fluorescein angiography (FA) in normal horses. Methods: A total of 25 healthy horses aged between 5 and 15 years. Methods: The horses were sedated with 15 microg/kg detomidine and 50 microg/kg butorphanol and dilated with topical tropicamide 1%. All angiograms were recorded after intravenous bolus injection of 10 mg/kg of fluorescein sodium solution. Results: Two successive angiographic phases could be discerned: the choriopapillary phase, starting at 46.95 +/- 9.48 s, and the retinal vascular phase, starting at 47.79 +/- 10.38 s. The retinal vascular...
Wilkie DA.Although many ophthalmic procedures can be performed on the standing horse, the decision to perform a procedure under sedation rather than general anesthesia must be made on the basis of the temperament of the horse, severity of the injury, and skill of the veterinarian. For example, veterinarians who are not comfortable with small suture material may find accurate repair of an eyelid laceration easier after general anesthesia rather than attempting to handle this suture in a moving patient. Correct use of nerve blocks and topical anesthesia will greatly facilitate examination, diagnosis, and ...
Gordon E, Sandquist C, Cebra CK, Heidel J, Poulsen K, Schlipf JW.To evaluate whether topical ocular application of 1% morphine sulfate would change corneal sensitivity and to identify the duration of action. Methods: Eight healthy adult horses. Methods: Corneal touch threshold (CTT) was measured in the center of one randomly selected eye of each horse by Cochet-Bonnet esthesiometer (Luneau Cochet-Bonnet Esthesiometer; Western Ophthalmics, Lynnwood, WA, USA). Immediately following baseline CTT measurement, 0.3 ml of 1.0% preservative-free morphine sulfate (Morphine Sulfate 25 mg/ml Preservative-free; Hospira, Lake Forest, IL, USA) (3 mg) was applied to th...
Ansari Mood M, Rajaei SM, Faghihi H, Ghiadi A.This study was performed to evaluate the effect of topical 1% cyclopentolate hydrochloride on tear production (STT), intraocular pressure (IOP), and vertical pupil diameter (VPD) in healthy Turkman horses. Forty eyes of 20 clinically normal horses were used for this study, which were randomly assigned to two groups. Before instillation of 1% cyclopentolate, the baseline STT, IOP, and VPD of each group were recorded. Then, one drop of cyclopentolate was instilled randomly into one eye of each animal, and the contralateral eye served as control. Measurements were repeated at 20 minutes, 60 min...
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...
Wada S, Yoshinari M, Katayama Y, Anzai T, Wada R, Akuzawa M.A 2-year-old Thoroughbred filly presented with ocular pain and epiphora of the left eye. The pupil was miotic and the cornea edematous near the ventro-temporal limbus, but did not retain any fluorescein. The topical antibiotics and atropine and diclofenac, and systemic flunixin meglumine and antibiotic therapy did not resolve the condition. A pink and fleshy infiltrate developed near the limbus indicating nonulcerative keratouveitis. The anterior uveitis deteriorated as manifested by the presence of dyscoria, hypopyon, and organized fibrin in the anterior chamber. Ocular signs were improved by...
Pucket JD, Allbaugh RA, Rankin AJ, Ou Z, Bello NM.To compare efficacy and duration of effect on corneal sensitivity of 0.5% proparacaine hydrochloride, 0.5% bupivacaine hydrochloride, 2% lidocaine hydrochloride, and 2% mepivacaine hydrochloride solutions following ocular administration in clinically normal horses. Methods: 68 clinically normal horses. Methods: 60 horses were assigned to receive 1 anesthetic agent in 1 eye. For each of another 8 horses, 1 eye was treated with each of the anesthetic agents in random order with a 1-week washout period between treatments. Corneal sensitivity was assessed via corneal touch threshold (CTT) measurem...
Bentley E, Murphy CJ.A thermal cautery technique was used to treat spontaneous chronic corneal epithelial defects (SCCEDs) in 9 eyes of 8 dogs and 2 eyes of 2 horses. Animals were sedated, and a topical anesthetic was applied. A handheld thermal cautery unit was then used to make multiple, small (< or = 1 mm in diameter), superficial burns throughout the affected area. The cautery unit was applied just until the slightest degree of contraction of the collagen fibrils was observed. After the stromal bed of the defect was treated, a rim of epithelium that extended approximately 1 mm around the denuded stroma was ...
Gunsalus K, Taylor R, Croix N.To report the clinical history, surgical management, and histologic findings of meibomian gland calcification and osseous metaplasia in a horse. Methods: A 21-year-old Selle Français gelding presented with a 9 months history of blepharitis, blepharospasm, and epiphora affecting the right eye. The horse was diagnosed with meibomianitis and impaction with associated granulomas, but not treated surgically for 6 years. Methods: Physical and ophthalmic examinations, and systemic bloodwork were performed. A diamond burr debridement was performed on a corneal ulceration, and meibomian gland nodul...
Tofflemire K, Whitley EM, Allbaugh R, Ben-Shlomo G, Griggs A, Strong T, Whitley RD.To evaluate the effect of topical ophthalmic 0.005% latanoprost alone and in combination with 0.1% diclofenac on healthy horses. Methods: Twelve healthy adult horses. Methods: A randomized, masked crossover design was used with horses divided into three groups for once daily treatment in one randomly selected eye. For arm 1 of the study, Group D (n = 3) received 0.1% diclofenac, Group L (n = 3) received 0.005% latanoprost, and Group DL (n = 6) received 0.005% latanoprost and 0.2 ml of 0.1% diclofenac. For arm 2 of the study, horses from Group D and L were placed into Group DL and horses from G...
Nardi S, Nuti M, Nocera I, Sgorbini M, Marmorini P, Barsotti G.This study assesses lacrimal secretion in healthy foals within 48 hours after birth and evaluates their variations in lacrimal secretion and menace response appearance during the first month of life. A total of 31 Standardbred foals were evaluated. Foals were housed with their dams in 4 × 4 m boxes throughout the study. A complete ophthalmic examination was performed for each animal enrolled in the study, including the foals' dams which were used as a control group to compare the lacrimal secretion of foals at birth with that of adult horses. In foals, the Schirmer Tear Test I (STT I) and m...
Gerard MP, Wotman KL, Komáromy AM.Infectious conditions of the equine head are commonly encountered in clinical practice. Pathogenic bacterial, viral, and fungal organisms may localize in the extensive nasal passages, paranasal sinuses, and guttural pouches, creating a range of clinical signs and conditions that can be severe enough to lead to unexpected fatality. Renewed interest in equine dentistry has led to a greater recognition of dental disease that is associated with infection. This article focuses on bacterial and fungal infections of the main anatomic regions of the equine head, where advances in diagnosis and managem...
