Multiple congenital ocular anomalies syndrome in a family of Shetland and Deutsches Classic ponies in Belgium

The multiple congenital ocular anomalies (MCOA) syndrome has been associated with the Silver phenotype only in a few equine breeds. This report describes the phenotypic and genotypic characteristics of MCOA in a family of Silver‐coated Shetland ponies including a 20‐year‐old stallion, 17‐year‐old mare and their 1.5‐year‐old female offspring. Another 7‐year‐old Silver female Deutsches Classic Pony descending from the same dam but from a different sire, was also examined. Each pony underwent a complete ophthalmic examination, tonometry, ocular ultrasonography and genotyping for the silver coat colour. The stallion had a thickened iris, temporal retinal atrophy and bilateral iridociliary and peripheral retinal cysts. All females presented more severe anomalies: cornea globosa, iridocorneal adhesions, miosis, hypoplastic granula iridica and poorly responsive pupils to light and to pharmacological mydriasis. Iris hypoplasia, anterior cortical cataracts and temporal retinal atrophy were detected in 2 mares. One female presented bilateral lens subluxation. Supero‐temporal cystic structures were confirmed ultrasonographically in all ponies. The stallion was heterozygous for the Silver mutation, whereas all females were homozygous. This is the first report of the MCOA syndrome in a family of Shetland ponies and a Deutsches Classic Pony in association with the Silver phenotype, in Europe.     

Phenotypic description of multiple congenital ocular anomalies in Comtois horses

Multiple congenital ocular anomalies (MCOA) and their relation to coat colour genotype have not yet been described in Comtois horses, unlike in Rocky Mountain Horses. The objectives of the study were to describe prevalence, nature and severity of congenital ocular anomalies relating to the PMEL17 (Silver) mutation in Comtois horses. Seventy‐four purebred Comtois and one half‐cross Comtois horses, aged 10 days to 18 years, were examined by transillumination, direct ophthalmoscopy and ultrasonography. Hair samples were collected from 34 horses for coat colour genotyping. Sixty‐six horses (88%) revealed cysts (65 horses) or abnormal thickness (one horse) of the ciliary bodies, most of them only diagnosed by ultrasonography. Cysts were localised in the nasal part of the eye in 8 horses. All these horses presented the silver phenotype with mane and tail being white or flaxen, or were chestnut with genetic testing confirming PMEL17 mutation. Of these, 39 (58%) showed MCOA‐syndrome with iridal hypoplasia (100%), cataract (85%), cornea globosa (56%) and lens luxation (8%). Only 8 bay mature horses (11%) were classified as being disease‐free. Genetic testing confirmed that cyst‐phenotype horses were heterozygous carriers for the Silver mutation, MCOA‐phenotype horses were homozygous carriers, and bay horses were noncarriers. Bay homozygous carriers had significantly lighter coat colour than heterozygous carriers. One foal with heterozygous mutation had normal eyes. Thus, MCOA‐syndrome related to PMEL17 mutation is overrepresented in Comtois horses, and should be taken into consideration for breeding purposes. Ultrasonography permitted detection of cysts in all Silver carriers apart from one, some of them being localised in the nasal part of the eye.     

Equine Multiple Congenital Ocular Anomalies (MCOA) syndrome in PMEL17 (Silver) mutant ponies: five cases

Objective To describe the clinical phenotype and genetics of equine Multiple Congenital Ocular Anomalies (MCOA) syndrome in PMEL17 (Silver) mutant ponies. Animals studied Five presumably unrelated ponies. Procedures The ponies were examined under field conditions in their barn by slit lamp biomicroscopy, indirect ophthalmoscopy, and applanation tonometry. Blood was collected and genomic DNA extracted for MCOA genotyping using the PMEL17ex11 marker. Results One pony solely presented with temporal ciliary body cysts, suggestive of the less severe Cyst phenotype of MCOA; the animal was heterozygous at the MCOA locus. Multiple bilateral anterior segment anomalies were identified in four ponies, consistent with the more severe MCOA phenotype characterized by cornea globosa, iris hypoplasia, encircling granula iridica along the pupillary ruff, and cataracts. These animals were homozygous for the mutant MCOA allele. Four of the ponies had a silver dapple or chocolate coat color with white or flaxen manes and tails. Silver dappling was masked by the palomino coloring of a 5th pony that was homozygous at the MCOA locus. Conclusions The MCOA syndrome can be seen in ponies. The results of both clinical evaluation and genotyping resembled the previously described MCOA of both Rocky Mountain and Kentucky Mountain Saddle horses.     

Congenital ocular abnormalities of Rocky Mountain Horses

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 temporally. Curvilinear streaks of retinal pigmented epithelium extending from the peripheral temporal retina marked the boundary of previous retinal detachment in 189 horses. Retinal dysplasia was detected in 125 horses. Multiple ocular anomalies were evident in 71 horses and were always bilateral and symmetrical. Affected eyes had a large, clear cornea that protruded excessively and had an apparent short radius of curvature, a deep anterior chamber, miotic and dyscoric pupil, and iris hypoplasia. Pupillary light responses were decreased or absent and pupils failed to dilate after repeated instillation of mydriatic drugs in horses with multiple ocular anomalies. Less frequently encountered abnormalities included peripheral iridocorneal adhesions and goniosynechiae. Congenital cataract was always present in eyes with multiple abnormalities. Intraocular pressures did not differ among horses with normal eyes and horses with multiple ocular abnormalities. Histologic examination of eyes corroborated the clinical appearance.     

Recurrent adnexal lymphoma in a horse

Lymphoma is a relatively uncommon neoplasm in the horse; however, it is considered the most common neoplasia of the equine haemolymphatic system. Limited reports of adnexal lymphoma have been documented in the literature, with no known reports of recurrence nearly a decade after mass excision. The objective is to describe a case of recurrent adnexal lymphoma in a 20-year-old Quarter Horse gelding presented to the Ophthalmology service at the University of Florida Veterinary Hospital (UFVH) for evaluation of a solitary subconjunctival mass of the right eye (OD). A focal, pink, fleshy mass associated with the dorsomedial bulbar conjunctiva was noted. An excisional biopsy was performed. Histopathology revealed lymphoma with clean margins. The client declined staging and further therapy at the initial visit. Approximately 8 years later, the horse began to exhibit intermittent mild to moderate diffuse swelling of the conjunctiva OD. Six months after onset, the swelling worsened acutely and was accompanied by severe swelling of the left conjunctiva (OS). The horse then returned to UFVH and was diagnosed with diffuse, bilateral conjunctival lymphoma. Humane euthanasia was elected. T cell lymphoma was confirmed with immunohistochemistry performed post-mortem. At necropsy, neoplastic tissue was observed throughout the adnexal and ocular tissues of both eyes and in the submandibular lymph nodes. Adnexal lymphoma is an uncommon neoplasm in the horse. To the authors’ knowledge, this is the first documentation of a nodular adnexal lymphoma that involved an 8-year period without recurrence followed by development of diffuse, bilateral disease. Typically, surgical excision of the nodular form of lymphoma involving the extraocular tissues yields an improved prognosis compared with the diffuse form of the disease. Further investigation is necessary to determine if nodular forms of adnexal lymphoma represent early stages of diffuse extraocular or systemic disease.     

Presumed post‐traumatic ocular chondrosarcoma with intrathoracic metastases in a cat

An indoor‐only, 5‐year‐old, spayed female domestic shorthair cat presented for an ophthalmic examination of the left eye. An intraocular tumor with secondary glaucoma and blindness was diagnosed; the globe was enucleated and sent for histopathological examination. Gross examination revealed a solid white mass filling the entire vitreous space and replacing the iris and ciliary body. The lens and retina appeared to be similarly replaced by the neoplasm. Histological examination revealed a complete loss of the internal ocular structures, with a ruptured capsule as the only remnant of the lens within an extensive malignant mesenchymal neoplastic cell proliferation. The cells were polygonal, with well‐defined cytoplasmic borders and abundant weakly basophilic cytoplasm, embedded within the islands of chondroid matrix. No neoplastic invasion of the sclera was apparent. The animal died 6 months after the enucleation due to respiratory distress. Gross examination revealed numerous firm, white to tan nodular masses with smooth to mildly irregular surfaces dispersed throughout the parietal pleura, thoracic surface of the diaphragm, tracheobronchial and mediastinal lymph nodes, pericardium, and lungs. On cross‐section, the neoplastic nodules were solid and variably translucent, resembling hyaline cartilage. Histologically, these nodules were similar to the neoplasm identified earlier in the left globe. Metastasis of post‐traumatic ocular chondrosarcoma has not yet been described in cats. This is therefore believed to be the first report of metastases of this type of neoplasm in cats. This case adds to the limited set of data on the outcome of this type of tumor.     

A case of canine ocular onchocercosis in Portugal

Onchocercosis is a newly recognized disease in dogs that has been reported with higher frequency in Europe and in the United States. We report a case of a 3‐year‐old male mongrel stray dog from the Algarve region (South Portugal) who had a retrobulbar granuloma containing a filaroid nematode of the genus Onchocerca. A gravid adult female parasite was embedded in a granulomatous inflammation adjacent to the sclera beyond the retina. The parasite was 191 to 267 μm in diameter (mean = 225 μm), surrounded by a cuticule and owing a uterus that was filled with small unsheated microfilariae. The cuticule consisted of two separated layers in longitudinal sections. The external layer had cuticular ridges and the internal layer contained striations. Sequencing of the COI and ND5 mitochondrial genes confirmed the identity of this parasite as Onchocerca lupi. Furthermore, the first sequence of the 12S mitochondrial gene is reported in this study.     

Abnormal ocular pigment deposition and glaucoma in the dog

The combined occurrence of ocular pigment deposition and glaucoma has been described in Cairn Terriers. Recently, this condition was also observed in two other breeds: the Boxer (two cases) and the Labrador Retriever (one case). Six dogs were referred to the Ophthalmology section of the Department of Clinical Sciences of Companion Animals and to a private referral clinic because of glaucoma or blindness in one or both eyes. In five cases ophthalmic examination showed pigment depositions in the sclera around the entire circumference of the perilimbal zone. Eight enucleated eyes (four eyes of two Cairn Terriers, three eyes of two Boxers and one eye of a Labrador Retriever) were examined microscopically. All eyes showed the same findings: an extensive infiltration of large melanin-containing cells with an eccentric nucleus, located in the iris, ciliary body, retina, choroids and sclera. Transmission electron microscopy of two of the examined eyes revealed that the morphology of most of these cells was consistent with melanophages. While reports in the veterinary literature concerning this condition are limited the cells concerned have been described to be melanocytes. Further research is needed to conclusively identify the cell type. As described in the present report, the histologic and transmission electron microscopic findings suggest a different etiology of the ocular pigment deposition and glaucoma compared with the pigment dispersal syndrome in humans.     

Idiopathic ocular and nasal granulomatous inflammatory disease in a dog

A young female Akita presented for ocular and nasal lesions. Examination showed bilateral 360 degree limbal masses that extended onto the peripheral cornea. In addition, intranasal granulomatous masses were observed by rhinoscopy. Histopathologic examination with immunohistochemical staining showed that these masses were almost identical and were classified as an idiopathic, T-cell rich, granulomatous inflammation. The dog responded well to anti-inflammatory medication and the disease remains in remission 2 years after the initial presentation.     

Topical hypertonic saline as a treatment for ocular and nasal hirudiniasis in a dog

This case report describes ocular and nasal leech infestation (hirudiniasis) in a dog. The patient presented for a suspected ocular foreign body. The patient was sedated to allow proper examination, which revealed a leech foreign body attached to the bulbar conjunctiva adjacent to the inferotemporal limbus of the left eye. A 3.5% hypertonic saline solution was applied topically to the eye in four sequential drops, until the leech detached itself and was removed with a cotton bud. The affected eye was found to have a small corneal ulcer, a small area of scleral haemorrhage, and prominent lymphoid follicles within the third eyelid. Approximately 5 min after the leech was removed, another leech emerged from the left nostril. The patient was sent home on chloramphenicol ointment for treatment of the corneal ulcer, was rechecked 4 days later by an American Board of Veterinary Ophthalmology resident (PM) and found to have a normal ocular exam. This case report highlights that topical hypertonic saline solution (3.5%) can be an effective and easily prepared treatment for ocular and nasal hirudiniasis in veterinary patients.     

Idiopathic granulomatous disease with ocular adnexal and cutaneous involvement in a dog.

Idiopathic granulomatous disease was the cause of bilateral eyelid masses and additional ocular adnexal disease in a dog. Histologically similar granulomas developed concurrently in distant sites including the limbs, prepuce, and testicles. Periodic resolution and redevelopment of the masses were observed and were unaffected by corticosteroid treatments. Rapid diminution of some of the masses was found after treatment with polyethylene glycol modified L-asparaginase, but poor client compliance and episodes of spontaneous resolution of some of the masses made it difficult to accurately assess effectiveness of treatment. Clinicians should be aware that ocular adnexal granulomas may simulate neoplasms and be a component of a more widespread disease process.