Corneal plaque containing levofloxacin in a dog

A 13‐year‐old castrated male Yorkshire terrier developed a corneal ulcer 2 weeks after intracapsular lens extraction (ICLE) in the right eye. The corneal ulcer was treated with levofloxacin eye drops. A plaque with a white luster developed in the central cornea 2 weeks after treatment with levofloxacin eye drops. The corneal plaque was surgically removed under inhalant anesthesia. The corneal plaque displayed antimicrobial activity against Escherichia coli. Furthermore, levofloxacin content in the plaque was confirmed by matrix‐assisted laser desorption/ionization time‐of‐flight/time‐of‐flight (MALDI‐TOF/TOF) mass spectrometry (MS). The corneal ulcer completely resolved 2 weeks after the surgical removal of the corneal lesion and replacement of levofloxacin eye drops with tobramycin eye drops. Although the topical use of levofloxacin is unlikely to lead to corneal chemical deposits due to the high water solubility of the drug compared to other topical fluoroquinolones, this patient developed corneal plaque of the antibiotic drop.     

Treatment of corneal squamous cell carcinoma using topical 1% 5‐fluorouracil as monotherapy

The purpose of this report is to discuss the use of topical 1% 5‐fluorouracil as a sole therapy for canine corneal squamous cell carcinoma (SCC). A 12‐year‐old castrated male pug was evaluated for a well‐demarcated, central, 3 mm in diameter, pale pink, raised, right corneal mass. An incisional biopsy was obtained using a #64 beaver blade after topical anesthesia and without sedation. A definitive diagnosis of corneal SCC was obtained after histopathologic evaluation of the biopsy. Topical 1% 5‐fluorouracil ointment was applied to the right eye four times daily for 2 weeks followed by no treatment for 2 weeks, then treatment again twice daily for 2 weeks. The cornea remained free of recurrence 10 months after cessation of treatment. In dogs affected with corneal SCC, topical 1% 5‐fluorouracil monotherapy may be a viable and cost‐effective treatment option with minimal side effects. This chemotherapy agent may also have an effect on corneal pigmentation. Chronic cyclosporine therapy did not contribute to the pathogenesis of corneal SCC in the case described.     

A cross‐linked hyaluronan gel accelerates healing of corneal epithelial abrasion and alkali burn injuries in rabbits

Objective To evaluate the efficacy of a chemically modified and cross‐linked derivative of hyaluronan (CMHA‐SX) for treatment of corneal epithelial abrasion and standardized alkali burn injuries. Animals Twelve female New Zealand white rabbits in two groups were used. Procedures Bilateral 6‐mm diameter corneal epithelial abrasions were made in each of six rabbits in one group and 6‐mm standardized alkali burn injuries were made in the second group. A 1% CMHA‐SX formulation was applied topically four times per day in right eye of each rabbit for 1 week, and phosphate buffered saline (PBS) was placed in left (control) eye of each rabbit. The wound size was determined by staining with 1% fluorescein and photographed at the slit lamp with a digital camera at 0, 1, 2, 3 days postoperatively in the first group and 0, 1, 2, 3, 7, 12 days in the second group. Rabbit corneas were collected for histological examination on day 7 in the first group and day 12 in the second group. Results Closure of corneal wound in the abrasion model was complete in the CMHA‐SX treated eye by 48 h. The wound closure rate and thickness of the central corneal epithelium in the CMHA‐SX treated group was greater than in control eyes for both the abrasion and alkali burn injuries. Moreover, the CMHA‐SX treated cornea exhibited better epithelial and stromal organization than the untreated control cornea. Conclusions Chemically modified and cross‐linked derivative of hyaluronan improved corneal wound healing and could be useful for treating noninfectious corneal injuries.     

Mortierella wolfii keratomycosis in a horse

Purpose To describe a case of superficial keratomycosis caused by Mortierella wolfii (M. wolfii) in a horse. Methods A thoroughbred filly was presented with painful right eye of 2 days’ duration. A superficial corneal ulcer was observed ventrally together with multifocal punctuate opacities axially. Samples were collected by swabbing and scraping the ulcerated lesion and submitted for microbiologic and cytologic examination. Results Microscopic evaluation of debrided corneal tissue revealed the presence of nonseptate fungal hyphae, and culture of a corneal swab yielded fungal growth. Medical treatment with topical antifungal, antibiotic and autogenous serum and systemic anti‐inflammatory resolved the problem within 2 weeks. Conclusions Cytologic evaluation of a corneal scraping was useful to make a clinical diagnosis of keratomycosis. Based on the mycological characteristics, the fungus isolated from the corneal lesion was identified as M. wolfii. To the authors’ knowledge, this is the first case report of equine keratomycosis associated with this fungus, although the organism is known to infect various organs of cattle.     

An unusual case of feline acute corneal hydrops: atypical disease presentation and possible in vivo detection of Descemet's membrane detachment in the cat's unaffected eye

A 1‐year‐old, female spayed, domestic shorthair cat presented for blepharospasm of the right eye. Slit‐lamp biomicroscopic examination showed focal corneal ulceration and presumptive keratomalacia of the right eye. Examination of the left eye was normal apart from a focal endothelial opacity. Within the first 24 h of medical management, the right eye developed marked corneal edema and globular anterior protrusion of the corneal surface consistent with feline acute corneal hydrops (FACH). Surgical management consisted of a bridge conjunctival graft, nictitating membrane flap, and temporary tarsorrhaphy. Resolution of corneal edema and pain occurred in the right eye within 24 days. Spectral domain optical coherence tomography (SD‐OCT) of the anterior segment was performed in both eyes. Conjunctival tissue from the bridge graft precluded examination of deeper corneal structures in the right eye. The left eye displayed a focal separation of the corneal endothelium and Descemet's membrane from the overlying stroma. These SD‐OCT findings are similar to the analogous syndrome found in humans and represent a potential etiology for FACH of the right eye in the case presented here. Unfortunately, the cat was lost to follow‐up and the progression of this lesion to FACH in the left eye could not be determined.     

A new treatment for presumed corneal epithelial inclusion cyst in a shih-tzu dog

An 8-year-old female shih-tzu was assessed for a 3-year history of yellow intrastromal material in the right eye. Slit-lamp biomicroscopy showed a yellow lesion in the upper half of the cornea, superficial corneal neovascularisation and oedema with negative fluorescein staining in the right eye. Ultrasound biomicroscopy revealed a nearly anechoic cystic space surrounded by hyperechoic oedematous cornea separating the stroma at three-quarters of the corneal depth. Two partial-thickness corneal incisions were performed around the lesion under topical anaesthesia. After cytology and culture sampling, intrastromal flushing was performed. A yellow viscous necrotic tissue was identified with no microorganism or evidence of tumour formation. Antibiotics, anti-inflammatories and a bandage contact lens were applied. Ultrasound biomicroscopy confirmed no recurrence 8 days later. Corneal neovascularisation and oedema gradually resolved through a 2-week follow-up. There was no recurrence in the subsequent 8 months.     

Curvularia keratomycosis in a dog

A 10‐year‐old, spayed female Bichon Frise was referred to the Veterinary Medical Center of the University of Florida with a 6‐week history of blepharospasm and a nonhealing ulcer of the left eye. Ophthalmic examination revealed a 3–4 mm diameter corneal ulcer with faint edema at the lesion edge, and a raised grayish area on the paraxial cornea near the 2 o’clock position. Cytological testing revealed fungal hyphae and extracellular cocci. Culture of the lesion found heavy growth of Enterococcus faecalis and Curvularia spp. Treatment with a combination of topical antibiotics (polymyxin B, sulfate/trimetoprim, and 10% sulfacetamide sodium), 1% miconazole, autologous serum, and 5% hypertonic saline was instituted. After 8 days of medical therapy, an improvement of clinical signs was noted, and 15 days after initiation of treatment, the ulcer was healed with minimal corneal scarring.     

In vivo confocal microscopy of equine fungal keratitis

Objective To describe in vivo corneal confocal microscopy of horses with fungal keratitis and correlate findings with clinical, histopathological, and microbiological evaluations of clinical cases and an ex vivo experimental equine fungal keratitis model. Animals studied A total of 12 horses with naturally‐acquired fungal keratitis and ex vivo equine corneas experimentally infected with clinical fungal isolates. Procedures Horses with naturally‐acquired fungal keratitis were examined with a modified Heidelberg Retina Tomograph II and Rostock Cornea Module. Confocal microscopy images of clinical isolates of Aspergillus fumigatus, Fusarium solani, and Candida albicans were obtained by examination of in vitro cultures and experimentally infected ex vivo equine corneas. Results Non‐specific in vivo corneal confocal microscopic findings in horses with fungal keratitis included leukocyte infiltrates, activated keratocytes, anterior stromal dendritic cell infiltrates, and vascularization. Linear, branching, hyper‐reflective structures that were 2–6 μm in width and 200 to >400 μm in length were detected in all horses with filamentous fungal keratitis. Round to oval hyper‐reflective structures that were 2–8 μm in diameter were detected in a horse with yeast fungal keratitis. The in vivo confocal microscopic appearance of the organisms was consistent with fungal morphologies observed during examination of in vitro cultures and infected ex vivo equine corneas. Conclusions In vivo corneal confocal microscopy is a rapid and non‐invasive method of diagnosing fungal keratitis in the horse. This imaging technique is useful for both ulcerative and non‐ulcerative fungal keratitis, and is particularly advantageous for confirming the presence of fungi in deep corneal stromal lesions.     

Treatment of corneal ulceration and bullous keratopathy using a nictitating membrane flap in two horses

Objective

The aim of this study was to describe placement of a nictitating membrane flap as a treatment for corneal ulceration and bullous keratopathy in two horses.

Animals Studied

A 13-year-old American Saddlebred mare presented for severe corneal edema, superficial stromal ulceration, and a central bulla of the left eye. A 4-year-old Trakhener stallion also presented with a large axial bulla of the left eye with concurrent severe corneal edema and a deep stromal ulcer.

Procedure

A complete ophthalmic examination was performed. Samples were obtained for corneal cytology, and both horses were started on aggressive medical therapy. Both underwent general anesthesia for placement of a nictitating membrane flap and a subpalpebral lavage system (SPLS).

Results

Corneal cytology for each horse revealed a mixed bacterial population. Moderate Pseudomonas aeruginosa was cultured from the mare, while Aspergillus species and a few Enterococcus gallinarum were cultured from the stallion. The bullae in both horses resolved at 3 and 4 weeks and vision returned in the affected eye 4.5 and 3 months postoperatively at the last follow-up, respectively.

Conclusion

Aggressive medical management with concurrent placement of a nictitating membrane flap is effective to treat bullous keratopathy in two horses. The described treatments could be used to treat horses that develop severe or progressive bullous corneal lesions.     

Coccidioides posadasii keratouveitis in a llama (Lama glama)

A 7-year-old male llama was examined for a 3-month history of weight loss, and unilateral keratouveitis. Clinical examination revealed nonulcerative corneal stromal abscessation, corneal vascularization, corneal edema, miosis, posterior synechia, cataract, and fibrin in the anterior chamber of the right eye. The left eye was normal. Histopathology of the right eye following enucleation revealed pyogranulomatous keratouveitis with intralesional fungal spherules consistent with Coccidioides spp. PCR amplification with DNA sequencing confirmed Coccidioides posadasii infection. To the authors' knowledge, this is the first reported case of ocular coccidioidomycosis in a llama.     

A remote fluorescein staining and photography protocol for monitoring of ulcerative keratitis in small animal patients: A pilot study

Objective

To describe a protocol for corneal ulcer monitoring utilizing daily fluorescein staining and evaluation of owner-acquired anterior segment images.

Animal studied

Nine client-owned small animal patients (eight dogs, one cat) diagnosed with superficial corneal ulcers at the University of Georgia Veterinary Capitalize Hospital.

Procedure(s)

In addition to routine ulcer therapy, patients were discharged with supplies to perform daily fluorescein staining including a Quikvue® cobalt blue light camera adapter. Fluorescein staining was performed daily, photographs and/or videos were acquired at home by the patient's owner(s), and images were analyzed daily by trained personnel. In-house examinations were performed weekly and within 24 h after the ulcer had appeared healed on photographs.

Results

All (9/9) owners were able to take interpretable photographs. The majority (6/9) of patients had images successfully detailing their ulcer healing progress. One (1/9) patient appeared healed on images, but on subsequent examination had persistent ulceration covered by third eyelid elevation. Two (2/9) patients had persistent ulceration, consistent on both images and examination, but exited the study prematurely prior to ulcer healing.

Conclusions

Remote fluorescein staining and image evaluation can be considered as an adjunct for monitoring ulcer healing but should not be used alone or as a substitute for ophthalmic examinations. Ulcers under the third eyelid have potential to be missed on image evaluation alone.     

CASE REPORT: Keratomycosis in a dog treated with topical 1% voriconazole solution

A 2‐year‐old Jack Russell Terrier was presented for treatment of a worsening corneal ulcer and keratomalacia following removal of a vegetative foreign body. The keratomalacia responded to topical gentamicin therapy; however, the eye became suddenly painful and at examination two areas of increased opacity had developed. Fungal keratitis was demonstrated by corneal scrape showing branching, septate fungal hyphae. Treatment with 1% voriconazole was effective in resolving the keratomycosis.     

Rose bengal positive epithelial microerosions as a manifestation of equine keratomycosis

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 found on corneal cytology from the sixth. Mixed bacterial infections were present in three eyes. The eyes of two horses with Aspergillus progressed to deep melting corneal ulcers that required surgical therapy. The microerosions remained superficial, but persistent in the other four eyes. Natamycin was utilized topically in all six horses. Transmission electron microscopy from case 6 revealed mucin layer disruption, an intact corneal epithelial cell layer, and fungal attachment to degenerating epithelial cells. The visual outcome was positive in all six horses, although healing was prolonged (48.5 +/- 14.5 days on average in the horses with no surgery; 62 days on average in the two horses that required surgery). CONCLUSIONS: Complete removal or full-thickness penetration of the corneal epithelial cell barrier may not be necessary to allow fungal adherence and initiation of keratomycosis in the horse. Prior to colonization and invasion of the horse cornea, fungi may induce changes in the mucin layer of the tear film that result in or are associated with rose bengal positive microerosions of the superficial corneal epithelium. Horses with painful eyes, and eyes with superficial, multifocal corneal opacities should have their corneas stained with both fluorescein and rose bengal as fungal microerosions may stain weakly, or not at all, with fluorescein, and may thus be mistaken for presumed 'viral keratitis' of the horse.     

Endocrinological characterization of an ovarian sex cord–stromal tumor with a Sertoli cell pattern in a Japanese Black cow

A Japanese Black cow was evaluated for prolonged post‐partum anestrus and enlargement of the right ovary. Transrectal ultrasonography revealed that the right ovary was markedly enlarged and had a solid appearance, while the left ovary was small and inactive. The presumptive diagnosis was directed towards granulosa‐theca cell tumour (GTCT) which was supported by markedly elevated plasma anti‐Müllerian hormone (AMH; 332.0 ng/ml), oestradiol (E₂; 103.3 pg/ml) and immunoreactive inhibin (ir‐INH; 2.1 ng/ml) in comparison with the diagnostic cut‐off points for bovine GTCTs. Since the cow had been infertile and had swelling of the udder, slaughter was chosen. Histopathological examination revealed that the tumour was an ovarian sex cord–stromal tumour (SCST) with a Sertoli cell pattern. These findings suggest that plasma AMH, ir‐INH and E₂ could be possible biomarkers for bovine ovarian SCST with a Sertoli cell pattern, whereas this case could not be distinguished from GTCTs based on endocrinological profile.     

Primary bilateral corneal nerve sheath neoplasm in a dog

A 15‐year‐old, neutered male, Shih Tzu cross developed progressive corneal stromal thickening and vascularization of the right eye, and 5 months later, of the left eye. Both eyes became blind due to extensive corneal opacification and were enucleated. Light microscopic examination revealed a diffuse corneal infiltrate of neoplastic mesenchymal cells, and immunohistochemistry revealed diffuse cytoplasmic vimentin immunoreactivity and variable cytoplasmic and nuclear immunoreactivity for S100 in the neoplastic cells. Transmission electron microscopy revealed desmosomes between contiguous cells, thread‐like cytoplasmic processes coated with basement membrane, extracellular bundles of collagen, and axonal degeneration consistent with features of a nerve sheath neoplasm. This is the first report of primary, bilateral corneal nerve sheath sarcoma in a canine.     

Microsporidial keratopathy in two dogs

A microsporidial keratopathy is described in two dogs. Both dogs presented with a unilateral stromal keratopathy characterized by multifocal coalescing opacities, and the diagnosis was made on histopathologic examination of keratectomy specimens. Transmission electron microscopy (TEM) on formalin‐fixed, paraffin‐embedded corneal tissue was performed in one dog, and the morphologic features were consistent with Nosema species infection. Both dogs were initially diagnosed and treated by superficial keratectomy. One dog received additional antifungal medication and underwent a penetrating keratoplasty following local recurrence two years later. No other systemic lesions attributable to the microsporidial infection were identified clinically. The clinical and diagnostic pathology findings, treatment, and follow‐up are discussed.     

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.     

Effect of topical administration of 1% morphine sulfate solution on signs of pain and corneal wound healing in dogs

OBJECTIVE: To evaluate the effect of topical application of a 1% morphine sulfate solution (MSS) on signs of pain and wound healing in dogs with corneal ulcers and examine normal corneas immunohistochemically for the presence of mu and delta opioid receptors. ANIMALS: 12 dogs. PROCEDURE: A 7-mm superficial corneal ulcer was surgically created in the right eye (OD) of 10 dogs, after which gentamicin solution and 1% MSS (n = 6) or saline solution (4) was administered topically OD 3 times daily. Blepharospasm, tearing, conjunctival hyperemia, aqueous flare, esthesiometer readings, and pupil size were recorded before and 30 minutes after treatment in all dogs. Ulcer size and days to completion of healing were recorded. Corneas from 4 treated and 3 control dogs were evaluated histologically. Normal canine corneas from 2 dogs not used in the study were evaluated immunohistochemically for the presence of mu and delta opioid receptors. RESULTS: Dogs treated with MSS had significantly less blepharospasm and lower esthesiometer readings than did control dogs. Duration of ulcer healing and findings of histologic evaluation of corneas did not differ between groups. Numerous delta and infrequent mu opioid receptors were identified in the corneal epithelium and anterior stroma of normal corneas. CONCLUSIONS AND CLINICAL RELEVANCE: Topical use of 1% MSS in dogs with corneal ulcers provided analgesia and did not interfere with normal wound healing. Both mu and delta opioid receptors were identified in normal corneas of dogs, although the mu receptors were present only in small numbers.     

Limbal conjunctival plaques and idiopathic eosinophilic conjunctivitis

A 4‐year‐old Welsh pony crossbred gelding was examined for acute onset of blepharospasm, epiphora and corneal oedema. Ophthalmic examination identified 2 conjunctival plaques located near the superior limbus of the left eye. The plaques did not resolve following treatment with topical triple antibiotic ointment, topical atropine ointment and oral flunixin meglumine and therefore a conjunctival biopsy was performed. Histology of the biopsy resulted in a diagnosis of eosinophilic conjunctivitis, which was treated with a topical corticosteroid ointment. Plaques resolved after 73 days of therapy but lesions did not improve with concurrent treatment with anthelmintics early in the course of therapy. Failure to identify an aetiological agent led to a diagnosis of idiopathic eosinophilic conjunctivitis. The conjunctival plaques have not recurred in the 10 months following discontinuation of therapy.     

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.