Corneal epithelial disease.

This article reviews conditions that primarily affect the corneal epithelium as distinct from corneal stromal diseases. Corneal ulceration is discussed elsewhere in this issue. The other corneal conditions include a variety of more subtle epithelial disease,which might colloquially be termed epitheliopathies, as well as uninfected indolent superficial ulcerations, corneal neoplasia, and eosinophilic keratitis. The fungal plaque is an unusual and somewhat chronic form of epithelial infection. Although less common than corneal ulcers, this collection of lesions may present uniquely challenging obstacles to diagnosis and identification of a cure. Newer therapies and surgical strategies are discussed.     

Nonsteroidal anti-inflammatory drugs in veterinary ophthalmology.

Uveitis is a common sequela to many ocular diseases. Primary treatment goals for uveitis should be to halt inflammation, prevent or control complications caused by inflammation, relieve pain, and preserve vision.Systemic and topical NSAIDs are essential components of the pharmaceutic armamentarium currently employed in the management of ocular inflammation by general practitioners and veterinary ophthalmologists worldwide. NSAIDs effectively prevent intraoperative miosis; control postoperative pain and inflammation after intraocular procedures, thus optimizing surgical outcome; control symptoms of allergic conjunctivitis;alleviate pain from various causes of uveitis; and circumvent some of the unwanted side effects that occur with corticosteroid treatment. Systemic NSAID therapy is necessary to treat posterior uveitis, because therapeutic concentrations cannot be attained in the retina and choroid with topical administration alone, and is warranted when diseases, such as diabetes mellitus or systemic infection, preclude the use of systemic corticosteroids.Risk factors have been identified with systemic and topical administration of NSAIDs. In general, ophthalmic NSAIDs may be used safely with other ophthalmic pharmaceutics; however, concurrent use of drugs known to affect the corneal epithelium adversely, such as gentamicin, may lead to increased corneal penetration of the NSAID. The concurrent use of NSAIDs with topical corticosteroids in the face of significant preexisting corneal inflammation has been identified as a risk factor in precipitating corneal erosions and melts in people and should be undertaken with caution[8]. Clinicians should remain vigilant in their screening of ophthalmic and systemic complications secondary to drug therapy and educate owners accordingly. If a sudden increase in patient ocular pain (as manifested by an increase in blepharospasm, photophobia, ocular discharge, or rubbing)is noted, owners should be instructed to contact their veterinarian promptly.     

Equine corneal surgery and transplantation.

Corneal disease is common in equine ophthalmology and requires vigilant monitoring and appropriate therapy to optimize the outcome.Many equine corneal diseases, particularly those that progress rapidly, may benefit from surgical intervention. These include descemetoceles, deep corneal lacerations and ulcers, corneal perforation/iris prolapse, ulcerative keratitis, corneal stromal abscesses, and corneoscleral neoplasia. Indications for corneal transplantation include optical, tectonic, therapeutic, and cosmetic purposes. Corneal transplantation is most often implemented in equine patients for tectonic and therapeutic reasons when a cornea is compromised by corneal stromal abscess, iris prolapse, or neoplasia.This article provides an outline of when to consider surgical intervention for corneal disease, the procedures available and expected outcomes, and how appropriate early surgical intervention can dramatically improve the end result.     

Topical treatment of non-healing corneal epithelial ulcers in dogs with aminocaproic acid

The potential efficacy of topical epsilon-aminocaproic acid, an antiplasmin agent, in the treatment of persistent corneal epithelial defects was evaluated in a study of the medical records of 44 dogs, in which 51 eyes had been diagnosed with a corneal epithelial defect lasting more than 10 days, with no apparent underlying cause. At an initial examination all the affected eyes had had non-adherent epithelium removed. Thirty-four of the eyes in 28 dogs examined between January 2000 and March 2003 were also treated by the topical application of a solution of 35.7 mg/ml ophthalmic aminocaproic acid three times a day; the other 17 eyes in 16 dogs treated between October 1997 and March 1999 had received only topical treatment with gentamicin in addition to the debridement. Both groups were assessed clinically at weekly intervals for a maximum of three weeks. The two groups had approximately the same breed distribution, and there were no statistically significant differences between them in terms of their age, sex, affected side or duration of the corneal erosions. After three weeks, 32 of the 34 eyes treated with aminocaproic acid (94.1 per cent) had been cured, compared with seven of the 17 eyes treated with gentamicin (41.2 per cent) (P=0.0001). No adverse drug reactions were reported.     

The use of hydrophilic contact lenses in corneal diseases of the dog and cat: A preliminary report

ABSTRACT
Two types of hydrophilic contact lenses were tested in dogs and cats as part of the therapeutic régime of recurrent corneal erosions, superficial corneal ulcers and keratoconjunctivitis sicca. It was found that the lenses are well tolerated by these species when properly fitted to the cornea. If the lenses were not properly fitted, they were lost before their therapeutic effectiveness could be evaluated. The use of hydrophilic contact lenses appeared to be beneficial in the treatment of superificial corneal ulcers and recurrent corneal erosions in the dog and cat, but ineffective in the treatment of keratoconjunctivitis sicca.     

Multiple striate keratotomy: a treatment for corneal erosions caused by epithelial basement membrane disease

Objective To study the efficacy of multiple striate keratotomy for the treatment of persistent corneal erosions suspected to be caused by primary corneal epithelial basement membrane disease.
Design A retrospective study.
Animals 16 dogs, three cats and one Australian dingo.
Procedure A technique called multiple striate keratotomy was used to treat twenty animals suffering from persistent corneal erosions.
Results All persistent corneal erosions healed with only one treatment. Most cases healed within 2 weeks. One case developed a second erosion in the same eye but in a different position to the original erosion.
Conclusions Multiple striate keratotomy is a safe, effective and well tolerated technique for the treatment of persistent corneal erosions thought to be caused by corneal epithelial basement membrane disease.     

Qualitative tear film disease

Abnormalities of the lipid and mucin components of the preocular tear film may result from diseases of the eyelid margins and conjunctiva. Chronic keratoconjunctivitis with epithelial edema and superficial corneal neovascularization, with or without ulceration, characterizes qualitative tear diseases. Tear components other than lipid and mucin that carry probable clinical significance include tear proteins, all-trans retinal, cholesterol, glucose, and electrolytes. Although less common than quantitative or aqueous deficiencies, qualitative abnormalities are recognized as primary or secondary causes of ocular surface disease in companion animals.     

Corneal fungal disease in small animals

Corneal fungal diseases, including fungal keratitis and stromal abscess, are uncommon in small animals. Ocular infection secondary to systemic mycosis is reported far more frequently. Suspicion of a fungal corneal ulcer should be raised based on a history of underlying trauma, especially with plant material, geographic location, chronic use of topical antibiotics or corticosteroids, or an extremely prolonged course of disease despite appropriate treatment. Clinical signs observed with fungal keratitis may include blepharospasm, epiphora, miosis, corneal opacity, and vascularization. Unfortunately, none of these signs is specific to fungal infection. If fungal keratitis is suspected or confirmed, then aggressive medical therapy should be instituted. Medications used include topical antifungals, parasympatholytics, anticollagenases, and antibacterials as well as systemic anti-inflammatory drugs. Because there are very few fungicidal medications, the course of medical treatment for fungal corneal disease requires a prolonged duration with frequent re-examination and assessment. Surgical treatment is sometimes required to save the eye and vision. Surgeries to be considered include debridement, conjunctival graft placement, and corneal transplantation.     

Corneal surgical techniques

Although challenging from a technical perspective, many corneal surgical procedures can be mastered by the general practitioner. This article describes a number of procedures that can potentially save both the eye and vision. Procedures include corneal laceration repair, conjunctival pedicle graft, tarsoconjunctival island graft, advancement graft, total conjunctival graft, frozen tectonic corneal graft, porcine small-intestine submucosa graft, and superficial keratectomy. In addition to considerations on how to properly perform these procedures, emphasis is placed on common causes of failure and how to avoid them.     

Corneal diseases of rabbits.

Corneal diseases are common in domestic rabbits. It is important to carefully evaluate the cornea and the entire eye when rabbit present with clinical signs such as squinting, tearing, or conjunctival hyperemia. Complete ophthalmic examination and general physical examination should be performed on all rabbits with corneal disease. Important diagnostic testing include culture and sensitivity, cytology, and fluorescein staining. Breed predispositions do not occur for most corneal problems, although some diseases are selected genetically in research rabbits. Corneal disease can be a primary condition or can occur secondary to other ocular or systemic disease.     

Corneal dystrophy in the dog and cat

Two types of epithelial dystrophy have been described in dogs, one each in the Boxer and Shetland Sheepdog breeds, both of which can be associated with corneal erosions. Medical therapy is recommended when erosions or tear film abnormalities are present. Stromal dystrophies documented in dogs appear to be a primary lipid deposition in various layers of the stroma, depending on the breed. Stromal dystrophies seldom lead to loss of vision, but vision loss has been observed in middle aged Airedale Terriers and aged Siberian Huskies. Treatment is usually unnecessary. The dog demonstrates two types of endothelial dystrophy, one of which (posterior polymorphous dystrophy in the American Cocker Spaniel) does not lead to corneal edema. Endothelial dystrophy observed in the Boston Terrier, Chihuahua, and other breeds is associated with progressive corneal edema, which can lead to bullous keratopathy and corneal erosions. Stromal and endothelial dystrophies, both of which are associated with rapid progression of corneal edema, occur rarely in the cat. Treatment of dystrophies with progressive corneal edema is symptomatic and palliative.     

Results of grid keratotomy, superficial keratectomy and debridement for the management of persistent corneal erosions in 92 dogs

Ninety-two cases of persistent corneal erosions in dogs were analyzed for breed, gender, age and which eye was affected. The results of the treatment of 92 persistent corneal erosions in dogs by superficial keratectomy (SK), grid keratotomy (GK), or debridement with a sterile dry cotton swab are presented. These techniques gave better rates of healing than have been previously reported. All cases of persistent corneal erosions healed in this study. However, it must be noted that three cases treated with debridement only failed to heal after several treatments and were eventually treated with SK. After one procedure 80 out of 92 (87%) had healed. After one procedure, 63% of cases treated with debridement healed, 100% of cases treated with SK healed, and 85% of cases treated with GK healed. At the first postoperative visit, 88% (21/24 cases) of ulcers treated by SK had healed, and 75% (39/52 cases) of ulcers treated by GK had healed. Only 25% of the persistent corneal erosions had healed at the first visit after debridement. All 24 cases of persistent corneal erosions treated with SK healed after one treatment in a mean +/- SD of 9.3 +/- 3.9 days (median of 7 days). Fifty-two cases were managed with GK; 44 (83%) of these healed with one procedure and eight cases required a second GK procedure to resolve. A mean +/- SD of 13.4 +/- 5.1 days (median of 11.5 days) following GK was required for the persistent corneal erosions to heal. Nineteen cases were initially managed by debridement with a dry cotton swab under local anesthesia. Sixteen out of these 19 debridement cases healed (giving an overall healing rate of 84%) in a mean +/- SD time of 23.4 +/- 11.1 days (median 21.5). There were three cases that did not heal with debridement. These cases were debrided at 10-20 day intervals for 30-60 days, and were then treated with SK. Two of these cases healed within 7 days, the other case required 18 days to heal. Sixty-three per cent of persistent corneal erosions treated with debridement healed after one procedure; however, only four out of 19 cases (21%) were healed at the first revisit. Complications were rare: corneal edema occurred in two cases following multiple GK, and excessive granulation tissue in one case was managed with a SK. There was the occurrence of an ulcer adjacent to the surgery site in four cases, two cases following GK and two cases following SK.     

Miniature pigs.

Miniature pigs have become popular pets in North America, and veterinarians of a variety of clinical specialties may be called on for their care. Successful collection of blood from these animals requires familiarity with the location of sites for venipuncture and knowledge of adequate methods of restraint. In this article, restraint and techniques for venipuncture are described, as well as techniques for cerebrospinal fluid collection, semen collection, and vaginal cytologic examination. Interpretation of hematologic, serum biochemical, and urinalysis data are also discussed. Methods for diagnosis of skin diseases, gastrointestinal parasitism, and enteric infectious diseases are included in order to provide the practitioner with the essential knowledge and skills for a variety of clinical pathologic studies of this unique pet.     

Relationship of dietary histamine to gastric ulcers in the dolphin

Gastric ulcers and erosions were found in a captive bottle-nosed dolphin. The results of gross and histologic examination suggested peptic digestion as the cause of ulcerations in the 1st compartment. The underlying cause of the erosions in the 2nd compartment appeared to be based on vascular rather than peptic mechanisms. Among the many factors responsible for these lesions, histamine, found in inadequately preserved dietary fish, was implicated as the initial ulcerogenic stimulant.     

Combined corneal lipid and calcium degeneration in a dog with hyperadrenocorticism: a case report

Corneal degeneration may occur with a deposition of lipids or calcium, or both. Calcareous and lipid degeneration may be either primary or secondary, associated with systemic diseases such as primary hyperlipidemia, hyperlipidemia associated with hyperadrenocorticism, and hypothyroidism. The authors report a case of bilateral corneal lipid and calcium degeneration in a 7-year-old female Poodle with hyperadrenocorticism. The condition worsened with Lysodren therapy but responded to surgical excision.     

Techniques for surgical correction of adnexal disease

The adnexa frequently requires the general practitioner to intervene surgically to manage underlying disease or as an ancillary aid in the management of corneal disease. Both acquired and hereditary disorders are encountered. This article reviews general anatomy and physiology of the eyelids and discusses indications for the more commonly performed surgical procedures and their execution. Procedures include tarsorrhaphy, management of eyelid lacerations, eyelid tumor resection, correction of upper and/or lower lid entropion, ectropion, a medial and lateral canthoplasty, colobomatous syndrome in the cat, management of distichiasis, trichiasis and ectopic ciliae, and reduction of a prolapse of the gland of the third eyelid. Finally a surgical pack inventory useful for adnexal surgery is described.     

Corneal epithelial inclusion cyst in a Llama

A 13-year-old, female Llama presented for evaluation of a limbal based corneal mass involving the OD of 4 months duration. The mass was excised en bloc by a nonpenetrating keratectomy, followed by placement of a conjunctival advancement flap covering the keratectomy site. The mass was submitted for histological evaluation. Histopathology identified the mass to be a corneal epithelial inclusion cyst filled with necrotic squamous and neutrophilic debris. Surgical excision was complete and considered curative with no signs of recurrence 3 months postoperatively. There was no known prior ocular trauma; however, a previously performed corneal biopsy for evaluation of recurrent epithelial erosions may have been an initiating cause.     

Modulation of proteolytic activity associated with persistent corneal ulcers in dogs

Canines affected with corneal lesions demonstrate increased proteolytic activity at the affected site. Canines that develop persistent corneal ulcers and maintain elevated levels of proteolytic activity respond to protease inhibitor therapy with polysulpated glycosaminoglycan, PSGAG. In this study, the proteolytic activity expressed in lacrimal fluid of canines was evaluated as normal (1.15 U mL⁻¹) or healed (1.19 U mL⁻¹). Six of the 26 dogs affected with persistent corneal ulcers, however, had a protease level consistent with the unaffected control animals. These dogs did not appear to respond to PSGAG therapy. Two pathophysiologies for persistent corneal ulcers are indicated. Identifying which mode is active could help determine the therapeutic treatment needed.     

Management of intraocular inflammatory disease

The uvea of the eye is divided into the anterior uvea (iris and ciliary body) and posterior uvea (choroid). Clinical signs of anterior uveitis include conjunctival hyperemia, corneal edema, aqueous flare, miosis, and a decrease in intraocular pressure. Inflammation of the posterior uvea often involves the retina as well resulting in a chorioretinitis. Clinical signs of chorioretinitis may include multifocal lesions in tapetal or nontapetal fundus, retinal detachment, and a decrease in vision. The etiology of uveitis is complex and includes numerous infectious, neoplastic, immune-mediated, and other diseases. Treatment is directed at the underlying systemic disease, if present, as well as symptomatic treatment for the eye. The diagnostic and therapeutic approach to a patient with uveitis is discussed.     

Viral diseases of the rabbit.

Viral disease in the rabbit is encountered infrequently by the clinical practitioner; however, several viral diseases were reported to occur in this species. Viral diseases that are described in the rabbit primarily may affect the integument, gastrointestinal tract or, central nervous system or maybe multi-systemic in nature. Rabbit viral diseases range from oral papillomatosis, with benign clinical signs, to rabbit hemorrhagic disease and myxomatosis, which may result in significant clinical disease and mortality. The wild rabbit may serve as a reservoir for disease transmission for many of these viral agents. In general, treatment of viral disease in the rabbit is supportive in nature.