Bilateral corneal dermoids associated with bilateral choroido-scleral colobomas in a cat: retinographic and optical coherence tomography study with surgical outcome and follow-up.

PURPOSE: To report a case of feline bilateral corneal dermoids, associated with unilateral iris coloboma and bilateral choroido-scleral colobomas in the same dorsolateral position, to describe retinographic and optical coherence tomography (OCT) characteristics, surgical outcome, and follow-up. ANIMAL STUDIED: A 9-month-old domestic shorthaired cat in which a full ophthalmoscopic examination was performed for evaluation of dermoids resulting in a diagnosis of associated iris coloboma in one eye and posterior colobomas in both eyes. PROCEDURES: Retinographies and OCT were performed under anesthesia to characterize the lesions of both fundi and allow surgical excision of the corneal dermoids. RESULTS: Ophthalmoscopy and retinographies revealed oval lesions in the dorsolateral fundi of both eyes. The lesions precisely mirrored their respective dermoids' (10-11 h OD and 1-2 h OS) clock positions, lacked a tapetum lucidum and choroidal vessels, and featured thin retinal vessels plunging to a posterior plane of the fundus. OCT crossline scans demonstrated preservation of retinal thickness and morphological layering in the fundic colobomas leading to the conclusion that the colobomas were purely choroido-scleral. The outcome of the surgical excision of the dermoids was satisfactory without hair recurrence and with acceptable corneal clarity making it possible to visualize the unilateral associated iris coloboma. Follow-ups did not reveal any fundic evolution nor retinal detachment. CONCLUSIONS: Retinographies and OCT made possible the characterization of choroido-scleral colobomas associated with corneal dermoids in this first reported case in a cat. We hypothesize that the recently described superior ocular sulcus might be the embryological link between these anomalies.

Use of subdermal hyaluronic acid injections and a free labial mucocutaneous graft for the repair of feline eyelid agenesis.

OBJECTIVE: To describe a technique to repair feline eyelid agenesis using a hyaluronic acid (HA) subdermal filler injection to allow for acute soft tissue expansion, followed by a free labial mucocutaneous graft. MATERIALS AND METHODS: Thirty-nine colobomatous eyelids in 24 feline patients with secondary keratitis were recruited to the study group. RESULTS: Keratitis and trichiasis were markedly resolved in 27/39 (69.2%) eyelids after a single procedure. Post-operative HA subdermal filler injections were required to resolve 5/39 (12.8%) eyelids that had mild post-operative trichiasis, and 1/39 (2.5%) eyelids that had post-operative lateral canthal collapse. Complications occurred in 6/39 (15.4%) cases, consisting of distal graft necrosis (n = 2 eyes), suture rubbing the cornea (n = 2 eyes), moderate trichiasis (n = 1 eye) and graft adherence to the episclera (n = 1 eye). CONCLUSION: The technique was successful in enhancing corneal protection, cosmesis and eyelid function and should be considered as a surgical option for any degree of eyelid agenesis in feline patients.

Use of free oral mucosal graft for treatment of feline eyelid agenesis in seven patients.

OBJECTIVE: To describe a simple and effective surgery for feline eyelid agenesis. PROCEDURE: Free oral mucosal grafts were harvested from the upper lips of the surgical patients. A recipient bed was created by incising the conjunctiva at the conjunctival-skin border and opening a space in the tissue with blunt dissection without removal of tissue. The free oral mucosal graft was sutured into the space with simple continuous suture pattern of 7-0 Vicryl. RESULTS: Eyelids were cosmetically acceptable at final examination, and areas of coloboma appeared less prominent. Patient comfort was improved in all subjects as subjectively noted by decreased blepharospasm. All grafts were successfully incorporated. All patients developed brown-colored crusting over the grafts within days of the surgery, which gradually resolved over a 4- to 6-week period. Three of seven patients developed few trichiatic hairs at the donor-recipient junction, and two of these patients had follow-up cryoepilation. CONCLUSION: For feline eyelid agenesis, free oral mucosal graft implantation was successful in creating space between fur and cornea with insertion of smooth-surfaced, hairless tissue, alleviating the discomfort of hair contacting the cornea. The extra tissue can also create a small overhang or fold of tissue (pseudo-lid) which may also be protective. For two cases, cryoepilation of few trichiatic hairs at the donor-recipient border was performed at a later date. As illustrated by case 3, use of a long and wide rectangular graft with squared edges is recommended to lessen the chance of trichiasis at lateral or medial edges of recipient-donor junctions.

Collie eye anomaly in a mixed-breed dog.

A 5-year-old, mixed-breed dog was presented for tetraparesis. Neurologic alterations included a decreased menace response in both eyes. Therefore, an ophthalmic examination was requested. The dog was visual, but menace response, dazzle and pupillary light reflexes were reduced bilaterally. Indirect ophthalmoscopy revealed bilateral optic nerve coloboma and severe choroidal hypoplasia. These lesions closely resembled the ophthalmoscopic features of Collie eye anomaly (CEA). In spite of treatment, the dog's condition worsened and the animal was therefore euthanized. Histology of the globes confirmed severe choroidal hypoplasia and optic disc coloboma in both eyes. The dog was diagnosed to have a lymphoma involving the spinal cord. The two entities were considered not related. As only moderate sight impairment was caused by the posterior segment anomalies, it is by chance that these lesions resembling CEA were found in this mixed-breed dog.

Vascular changes associated with chorioretinal and optic nerve colobomas in rats (Crj: CD(SD), IGS).

OBJECTIVE: Three female adult rats (Crj: CD(SD) IGS) with colobomatous anomalies were investigated. MATERIALS AND METHODS: The microvascular changes of the coloboma were studied using the techniques of fluorescein angiography, histology and scanning electron microscopy (SEM) of vascular corrosion casts. RESULTS: Fluorescein angiography revealed the pits of the optic disk as a dark hole with some abnormalities in vessel arrangement. Light microscopy confirmed the presence of attenuated lamina cribrosa, retinal dysplasia and marked dilation of the retinal veins. SEM revealed that the optic disk coloboma formed a crater-like pit and that central retinal vessels ran a tortuous course along the bottom and side of the crater. Capillaries in the optic nerve head were missing in the affected area. The central retinal veins were thick and had various changes such as strangulation, rough surface structures, mural voids and evaginations, which represent loss of integrity of the vascular wall. CONCLUSIONS: These vascular changes that are associated with colobomatous anomalies may impede the retinal circulation and be responsible for the fluctuating fluorescein pattern during fluorangiogram of affected animals. The lesions of the vascular wall may increase the subretinal fluid due to the leakage of fluid, thus causing the maculopathy or serous retinopathy, which is frequently associated with posterior pole coloboma.

Staphyloma in a cat.

A unilateral scleral staphyloma in an 18-month-old, female spayed Domestic Short-haired cat was treated with excision, primary closure and fascial graft. Other ocular abnormalities noted on examination included iris coloboma, anterior cortical cataract, focal lens equator flattening and retinal dysplasia. The staphyloma was presumed to be congenital in origin.

Collie eye anomaly in the rough collie in Sweden: genetic transmission and influence on offspring vitality.

Between 1989 and 1997, 8204 rough collies were examined for collie eye anomaly (CEA) at up to 10 weeks of age. All dogs were positively identified and the results were registered under the Swedish Kennel Club genetic health programme. A significant decrease in litter size occurred if one of two affected parents had coloboma (3.8 pups) compared with litters from two chorioretinal dysplasia- (CRD-) affected collies (5.2 pups) or litters by two normal collies (5.0 pups), indicating an influence of the coloboma genotype on offspring vitality. The prevalence of CRD in pups from normal x normal matings and CRD x CRD matings was significantly different from that expected under simple autosomal recessive inheritance (43 per cent versus 25 per cent and 85 per cent versus 100 per cent). The results are compatible with polygenic inheritance but not with simple autosomal recessive inheritance. CRD prevalence in offspring of CRD x coloboma matings was significantly lower than in pups of CRD x CRD matings, reflecting effects of the coloboma genotype on vitality. These results have important implications for breeding programmes and the genetic control of CEA.

Bilateral colobomas in a horse.

Bilateral true colobomas with retrobulbar cysts located over the optic nerves are described in an 8-year-old Quarterhorse mare with a history of progressive blindness. Colobomas result from the failure of an embryonic fissure to close and retrobulbar cysts result from eversion of the neuroectoderm through the colobomas. It could not be determined whether the small optic nerves and the scars, rosettes and disorganization of the cell layers in the retina were the result of concurrent dysplasia or were secondary to degeneration.

Neonatal ophthalmology.

This discussion of normal and abnormal findings on routine ophthalmic examination of the foal should prove useful to the equine practitioner who must provide counsel to the concerned owner and/or breeder. Early diagnosis and treatment of ocular abnormalities improve the prognosis for continued function and aid determination of the significance of lesions observed in later life.

Spontaneous eye lesions in laboratory animals: incidence in relation to age.

Examination of the eye in experiments designed to test the toxicity of drugs or chemicals is of considerable importance and the investigator must have a clear idea of the spontaneous eye changes he can expect in the test species. We have attempted to review the literature relating to commonly used laboratory animals--the rat, mouse, and dog as well as the hamster--but as there is still only a handful of workers that publish their findings, the literature is not fully comprehensive. Our own unpublished data have been used to try and provide a more complete account. There is, therefore, a considerable need for further work in this area and, in the future, newer techniques such as electron microscopy and histochemistry can help us in the understanding of the pathogenesis of age-related changes in laboratory animals.

Cross lid flap for repair of large upper eyelid defects.

A 2-stage technique for reconstruction of large, upper eyelid defects was adapted from a technique used in man for use in lower animals. The technique utilized a flap from the lower lid and was applied successfully in a dog with a melanoma and in 2 cats with colobomas.

Infiltrative corneal lesions resembling fibrous histiocytoma: clinical and pathologic findings in six dogs and one cat.

Infiltrating corneal lesions developed in 6 dogs and 1 cat. In each case, the site of origin appeared to be the corneal limbus. The lesions were characterized by continuous growth, a benign appearance, and a tendency to recur following excision keratoplasty. Each lesion was of a proliferative, inflammatory nature, histologically resembling fibrous histiocytoma. Of the 6 dogs in the series, 4 were Collies.

Visual defects in white-tailed deer from Michigan six case reports.

Six cases of unrelated visual defects in free-ranging white-tailed deer (Odocoileus virginianus) from Michigan are described. Two were congenital, two were of infectious etiology, one from central nervous neoplasia, and one from degenerative changes in lenses of both eyes.