Topic:Cataracts
Cataracts in horses refer to the clouding of the lens within the eye, leading to impaired vision. This condition can affect one or both eyes and varies in severity from small, non-progressive opacities to complete lens opacity resulting in blindness. Cataracts can be congenital, meaning present at birth, or acquired due to factors such as aging, trauma, or disease. Diagnosis typically involves a thorough ophthalmic examination using specialized equipment to assess the extent and impact on vision. Treatment options depend on the severity and underlying cause, with some cases potentially requiring surgical intervention. This page compiles peer-reviewed research studies and scholarly articles that explore the etiology, diagnosis, and management of cataracts in equine patients.
Phacoemulsification Combined with Pars Plana Vitrectomy: Outcome in Horses with Acquired Cataracts Associated with Uveitis. Cataracts resulting from equine recurrent uveitis (ERU) or other forms of uveitis are usually associated with rapid progression. ERU is the most common ocular disease cause of blindness and cause of cataracts in horses. The necessity for the posterior capsulorhexis (PC) during phacoemulsification (PE) is controversial. This study aimed to evaluate vision and complications after PE combined with pars plana vitrectomy (PPV) in horses with uveitis-associated cataracts and compare the PE technique with and without posterior capsulorhexis. Methods: Thirty-two eyes of 28 horses with uveitis-associat...
Equine uveitis: Outcome and adverse effects after one or two intravitreal low-dose gentamicin injections. Uveitis is common in horses, potentially turning chronic (persistent or recurrent) resulting in impaired vision or blindness. All mainstay therapeutics aims at controlling inflammation, but long-term or lifelong treatment is often needed with possibly severe side effects. Therefore, intravitreal injections with low-dose gentamicin (IVGI) have been used in attempt to give a long-lasting result with potentially less side effects. Objective: To retrospectively assess outcome and long-term complications following one or two low-dose IVGI in Swedish horses with chronic uveitis. Methods: Retrospecti...
Breed predispositions to congenital and juvenile cataracts in horses at two academic institutions. Determination of horse breeds predisposed to congenital and juvenile cataracts will enable investigations into potential genetic mechanisms for cataracts in horses. Objective: To investigate horse breed predispositions to congenital and juvenile cataracts in two academic referral populations. Methods: Retrospective case series. Methods: Medical record identification of horses diagnosed with congenital or juvenile cataracts at the Cornell University Equine Hospital (2000-2022) and the University of California-Davis (UCD) Large Animal Clinic (1990-2021). Signalment, examination findings and trea...
Preliminary evaluation of safety and migration of immune activated mesenchymal stromal cells administered by subconjunctival injection for equine recurrent uveitis. Equine recurrent uveitis (ERU), an immune mediated disease characterized by repeated episodes of intra-ocular inflammation, affects 25% of horses in the USA and is the most common cause of glaucoma, cataracts, and blindness. Mesenchymal stromal cells (MSCs) have immunomodulatory properties, which are upregulated by preconditioning with toll-like receptor agonists. The objective was to evaluate safety and migration of TLR-3 agonist polyinosinic, polycytidylic acid (pIC)-activated MSCs injected subconjunctivally in healthy horses prior to clinical application in horses with ERU. We hypothesized ...
Knowledge and practice of radiation safety in Brazilian equine veterinarians are less than optimal: An online survey. Exposure to ionizing radiation is an occupational risk for veterinarians due to the potential for carcinogenesis, reproductive disorders, cataracts, and hereditary genetic changes. This survey study aimed to identify the radiological protection practices routinely used by veterinarians who work with portable digital X-ray equipment in horses in Brazil and assess their knowledge regarding current legislation. A total of 120 voluntary participation questionnaires were sent to veterinarians who used portable digital radiographic equipment in horses nationwide. The frequencies of the answers were ...
Survey of ocular abnormalities in draft horses. To determine the prevalence of ocular disease in draft horses in the United States. Methods: Draft horses of various breeds and ages. Methods: Nondilated ophthalmic examination was performed using slit lamp biomicroscopy and indirect ophthalmoscopy. Intraocular pressures were measured when possible. Results: One hundred sixty-five draft horses were examined. Age range: 10 days to 33 years (mean 10.8 years, median 10 years); 87 geldings (52.7%), 71 mares (43.0%), 7 stallions (4.2%); 64 Percherons (38.8%), 51 Belgians (30.9%), 29 Clydesdales (17.6%), 15 Shires (9%), and 6 other draft bre...
Ocular abnormalities in the Icelandic horse with a focus on equine recurrent uveitis: 112 Icelandic horses living in Denmark and 26 Icelandic horses living in the United States. To describe the most common ocular abnormalities in the Icelandic horse with focus on equine recurrent uveitis (ERU) and association between ocular abnormalities and summer eczema and coat colors. Methods: A descriptive cross-sectional study. A complete physical and ophthalmic examination as well as measurement of serum titers for Leptospira serovariants was performed on Icelandic horses from Denmark (DK) and the United States (USA). Results: One hundred and twelve Icelandic horses living in DK and 26 Icelandic horses living in the United States were included in this study (total of 138 horse...
A retrospective histologic study of 140 cases of clinically significant equine ocular disorders. Ocular diseases are an important category in equine medicine; however, most articles regarding histologic ocular lesions in horses are exclusive to a specific condition and do not provide a complete review of clinically significant ocular disease frequency in a diagnostic laboratory. We reviewed sections of equine eyes from 140 cases (98 enucleations [biopsies] and 42 autopsies) with clinically relevant ocular alterations at 2 diagnostic centers in the United States. The most common primary conditions were non-traumatic keratitis (36), equine recurrent uveitis (ERU; 31), traumatic injuries (22...
[Intravitreal injection of low-dose gentamicin for the treatment of ERU-affected horses]. Aim of the study was the retrospective evaluation regarding vision and recurrence in equine recurrent uveitis (ERU)-affected horses treated by intravitreal low-dose gentamicin injection in Tierklinik Alt Sammit during the years 2006-2013. Methods: The study included 50 equine patients (61 ERU-affected eyes) of different age and breed with different stages of ERU. The solution for the injection contained 4.0 mg sterile gentamicin per eye. The injection was performed according to the procedure described by Pinard et al. in 2005 under general anaesthesia in lateral recumbency of the patient and...
Prevalence of owner-reported ocular problems and veterinary ocular findings in a population of horses aged ≥15 years. Previous studies suggest that ocular disease is common among aged horses but owners may fail to identify or underestimate their clinical relevance. Objective: To document the prevalence of owner-reported ocular disease in horses aged ≥15 years. In a subset of these horses, to document ophthalmic findings from veterinary examination and compare with owner-reported ocular disease, and to determine risk factors for veterinary ophthalmic findings. Methods: Cross-sectional study. Methods: Owners of aged horses completed a survey on management, clinical signs and medical history. Risk factors for ...
Intraocular lens power calculation for the equine eye. 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...
Disease and Surgery of the Equine Lens. Examination of the lens is critical, particularly when evaluating horses with visual impairment or performing prepurchase examinations. To adequately evaluate the lens, the pupil must be pharmacologically dilated. A cataract is any lens opacity. The size, density, and position of a cataract determine the impact on vision. Cataracts may be congenital or inherited or occur secondary to trauma or equine recurrent uveitis. Surgical removal is the only treatment option for vision impairing cataracts, but careful selection of surgical candidates is critical for successful outcomes.
The prevalence of ocular diseases in polish Arabian horses. Equine ocular diseases pose a medical challenge due to long-lasting and cost-consuming therapies as well as economic issues associated with potential decrease in value of affected horses. The scale of the problem is significant but difficult to precisely define because epidemiological data is limited and lacks consistency in presentation. To date, no retrospective studies specifically investigating Arabian horses have been published. Results: The aim of this cross-sectional study was to investigate the prevalence of ocular lesions and define the ocular diseases present in Arabian horses from b...
Descemet’s membrane detachment in horses; case series and literature review. 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...
Visual outcomes of phacoemulsification cataract surgery in horses: 1990-2013. To evaluate the long-term visual outcome of phacoemulsification lens extraction surgery in foals and horses and identify any unique postoperative complications that affect the visual outcome. Methods: This is a retrospective medical records study of phacoemulsification cataract surgery in 95 foals and horses from 1990 to 2013. Results: Cataracts were removed by phacoemulsification from 111 eyes of 95 horses ranging in age from 22 days to 26 years (average 8.0 ± 5.7 years). Forty-four of the 95 animals were foals (46.3%). Sixteen horses or foals had surgery bilaterally. One hundred and two eye...
Ophthalmological findings in a closed herd of Lipizzaners. There are no studies on the ophthalmic health status in the Lipizzaner breed. Objective: To perform an ophthalmological survey in a closed herd in 3 housing systems. Methods: All horses at the Federal Stud Piber, Heldenberg and the Spanish Riding School Vienna were subjected to ophthalmological examination. Findings were documented and correlated with factors such as age, gender, location and housing situation. The interrelation of abnormalities of different regions was determined by calculating accuracy. Pedigree analysis of horses affected by cataract was performed. Results: A total of 267 h...
Ocular abnormalities in healthy Standardbred foals. To determine the prevalence and describe ocular abnormalities in healthy Standardbred foals within 48 h of birth. Methods: One hundred and two neonatal foals. Methods: All foals had an unassisted delivery. On the basis of physical examination and the results of hematological and biochemical parameters, all foals were unaffected by systemic diseases. A complete ophthalmic examination was performed within 48 h of birth. Foals with ocular hemorrhages were re-examined weekly until the abnormalities were resolved. Results: 65/102 (63.7%) foals did not show ocular abnormalities, while in 37/102 (36....
A pilot study on the corneal curvatures and ocular dimensions of horses less than one year of age. Intraocular lenses (IOLs) have been implanted in adult equine eyes after cataract surgery. Foals and weanlings comprise a large proportion of those horses undergoing cataract surgery. Due to potential differences in the size and corneal curvature of the juvenile eye, it is not currently known whether implantation of adult IOLs is appropriate in foals and weanlings. The objective of the study was to measure the anterior chamber depth (ACD), central lens thickness (CLT), vitreous chamber depth (VCD), axial globe length (AGL) and corneal curvature of horses less than one year of age. The axial di...
Phacoemulsification and +14 diopter intraocular lens placement in a Saddlebred foal. 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...
Diode laser endoscopic cyclophotocoagulation in the normal equine eye. To determine the clinical and histologic effects of diode endoscopic cyclophotocoagulation (ECP) in the phakic equine eye. Methods: Phase I: 10 equine cadaver eyes. Phase II: four normal adult horses. Methods: Phase I: ECP probe angle of reach (AR) was determined. Multiple ECP energy levels: 0.75, 0.90, 1.05, 1.20, 1.35, 1.50 J, and the resulting visible and histologic ciliary process changes were evaluated. Phase II: Ocular quadrants were treated with ECP at 0.90, 1.14, 1.38 J, and a control. The contralateral eye underwent a sham operation. Tissue changes (clinical and histologic) were evalu...
Ophthalmic lesions in neonatal foals evaluated for nonophthalmic disease at referral hospitals. 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...
Phacoemulsification and implantation of foldable +14 diopter intraocular lenses in five mature horses. 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...
Multiple congenital ocular anomalies in Icelandic horses. 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...
A survey of ocular abnormalities in miniature horses. To determine the incidence of ocular abnormalities in miniature horses. Methods: Descriptive study. Methods: Fifty-three miniature horses. Methods: Ophthalmic examinations were performed using diffuse and focal illumination, slit-lamp biomicroscopy and indirect ophthalmoscopy. Coat color, mane and tail color, age and gender were recorded with results of ophthalmic examination. Results: Ocular abnormalities detected most frequently consisted of cysts arising from the posterior iris, ciliary body, and peripheral retina, curvilinear streaks of retinal pigmented epithelium extending from the perip...
Ocular anomalies in a herd of Exmoor ponies in Canada. To characterize the ocular anomalies, determine their recurrence in families and assess the mode of inheritance of the most prevalent anomalies through pedigree analysis in a herd of Exmoor ponies. Methods: Thirty Exmoor ponies residing in south-western Ontario, Canada. Methods: Ophthalmic examination was performed using direct ophthalmoscopy, slit-lamp biomicroscopy and indirect ophthalmoscopy, pre- and post-pupillary dilation. Following compilation of ocular findings, pedigree analysis was conducted to assess the recurrence pattern of specific anomalies in families and the data were tested f...
Current developments in equine cataract surgery. The purpose of this review is to discuss the evolution of equine cataract surgery over the past 50 years to its current stage. Equine cataract surgery is performed similarly compared with the techniques used in human ophthalmology and in other veterinary species. However, enough differences exist to make surgical lens removal and intraocular lens implantation in the horse an intrinsically unique endeavour. Due to the size of the adult equine globe, the introduction of species-specific instrumentation has provided the cornerstone to many of the changes made regarding surgical technique over the...
Long-term outcome after implantation of a suprachoroidal cyclosporine drug delivery device in horses with recurrent uveitis. To determine the long-term efficacy, complications, and duration of effect of a cyclosporine (CsA) suprachoroidal implant (CSI) in horses with equine recurrent uveitis (ERU). Methods: Horses with ERU were treated with a 6-mm diameter, 25 mg, reservoir matrix CsA implant in the deep sclera adjacent to the suprachoroidal space. Horses with follow-up >1 year were examined for frequency of uveitis episodes, complications, and vision at last recheck. Results: Data from 151 eyes of 133 horses from the USA and Europe that had CsA devices implanted for ERU were reviewed. Follow-up time ranged from 13 ...
Complications of ophthalmic surgery in the horse. Corneal transplantation, amniotic membrane transplantation, phacoemulsification cataract extraction, and laser glaucoma therapy are routine ophthalmic surgical procedures in horses. This article discusses the indications, techniques, and postoperative complications of these and other ophthalmic surgical procedures in horses. Meticulous and accurate anatomic repair can minimize postoperative complications to maintain positive visual outcomes in ophthalmic surgery of the horse.
Equine Multiple Congenital Ocular Anomalies maps to a 4.9 megabase interval on horse chromosome 6. Equine Multiple Congenital Ocular Anomalies (MCOA) syndrome consists of a diverse set of abnormalities predominantly localized to the frontal part of the eye. The disease is in agreement with a codominant mode of inheritance in our horse material. Animals presumed to be heterozygous for the mutant allele have cysts originating from the temporal ciliary body, peripheral retina and/or iris. In contrast, animals predicted to be homozygous for the disease-causing allele possess a wide range of multiple abnormalities, including iridociliary and/or peripheral retinal cysts, iridocorneal angle abnorm...