Corneal collagen cross-linking following superficial keratectomy as treatment for corneal endothelial cell dystrophy in dogs: Preliminary clinical study.

OBJECTIVE: To describe the outcome of corneal collagen cross-linking (CXL) combined with superficial keratectomy (SK) as treatment for corneal edema due to corneal endothelial dystrophy (CED) in dogs. ANIMALS STUDIED: Four eyes of four dogs (3 Shih Tzus and 1 English Cocker Spaniel) with corneal edema due to CED were treated with SK and CXL. Two were males, and two were females. PROCEDURE: Depending on corneal thickness, 500-700 µm of edematous cornea was removed by SK. Next, CXL was performed by irradiating the cornea with UVA (365 nm) at 3 mW/cm² irradiance for 30 min after soaking with 0.1% riboflavin in 20% dextran every three minutes for 30 minutes. One drop of riboflavin was instilled every three minutes during irradiation. Slit lamp biomicroscopy and optical coherence tomography were used to examine the cornea during the follow-up period. RESULTS: The corneas had focal to diffuse edema, and the average corneal thickness was 1553 (1282-1900) µm. All corneas showed a significantly reduced corneal thickness and regained marked transparency immediately after treatment; however, the opacity increased as the corneal thickness increased during the follow-up period. Corneal vascularization (n = 4) disappeared within a month. Corneal pigmentation (n = 1) and bullae (n = 1) were observed. All cases showed marked reduction in corneal thickness; however, transparency was improved in only one case. CONCLUSION: Collagen cross-linking with SK has the potential to reduce the corneal thickness in CED cases; however, a lasting clinically significant improvement of corneal transparency seems unlikely. As the added benefit of CXL to the SK procedure is unclear based on the results of this study, combined treatment of CXL and SK for the treatment of corneal edema caused by CED is currently not recommended in dogs.

OPHTHALMIC EXAMINATION IN COMMON KESTRELS (FALCO TINNUCULUS) FROM SOUTH KOREA.

The purpose of this study was to establish reference ophthalmic findings in the common kestrel (Falco tinnunculus). Twenty healthy adult kestrels were included in this study. Ophthalmic examinations included slit lamp biomicroscopy, fundus exam, Schirmer tear test, conjunctival bacterial culture and isolation, corneal touch threshold, tonometry, and corneal diameter measurement. Mean tear production was 7.4 ± 3.27 mm/min, and mean intraocular pressure measured via applanation tonometry was 10.5 ± 3.15 mm Hg. In addition, the mean corneal touch threshold was 29.8 ± 20.1 mm, and the mean corneal diameter was 9.8 ± 1.1 mm. Of the 25 conjunctival swabs, 23 (92%) yielded bacterial growth. Most of these bacteria were gram positive (69.6%); the most predominant genus was Staphylococcus. This study presents reference values for ophthalmic examinations in common kestrels.

INTRAOCULAR SILICONE BALL IMPLANTATION AFTER EVISCERATION IN A SLOW LORIS (NYCTICEBUS COUCANG).

A slow loris, Nycticebus coucang , was brought to Ji Dong Beom Animal Hospital from the National Institute of Ecology due to globe enlargement and frequent blepharospasm of the right eye. Ophthalmic diagnoses included glaucoma with posterior lens luxation and cataract. Because this animal was on exhibition at the National Institute of Ecology, preservation of the eyeball by intraocular silicone implantation following evisceration rather than enucleation was selected. Before the surgery, examination of the normal left eye was performed using Retcam and spectral domain optical coherence tomography. Three months later, the globe size was almost the same as the left eye; however, corneal edema remained.

Tumor-like lymphoplasmacytic conjunctivitis in the third eyelid in a dog.

This report aims to describe a case of tumor-like lymphoplasmacytic conjunctivitis in a 7-year-old spayed-female Pomeranian. On complete ophthalmic examination, a mass with papillary projections was noted on the bulbar surface of the right third eyelid. Debulking of the mass was performed while preserving as much of the third eyelid as possible. On the histopathological examination, the mass was diagnosed as lymphoplasmacytic conjunctivitis with mild epithelial hyperplasia. Although a slight regrowth of the mass was noted 3 weeks after surgery, intralesional injection of triamcinolone acetonide led to its disappearance. There was no further recurrence after 5 months.

Effect of topical anesthesia on evaluation of corneal sensitivity and intraocular pressure in rats and dogs.

OBJECTIVE: To determine the effect of 0.5% proparacaine in tonometry by evaluating corneal touch threshold (CTT) and intraocular pressure (IOP). ANIMAL STUDIED: Nine rats (18 eyes, Sprague-Dawley) and 10 dogs (20 eyes, Beagle) PROCEDURES: The IOP and CTT were measured in each eye before and after topical anesthesia with 0.5% proparacaine. The IOP was evaluated using Tonopen for dogs and Tonolab for rats. The corneal sensitivity was evaluated by CTT through a Cochet-Bonnet aesthesiometer. RESULTS: The mean IOP was not significantly changed in rats or dogs before and after topical anesthesia. However, after application of proparacaine, CTT was significantly increased in both animal groups compared with that before application of proparacaine. CONCLUSION: From this study, topical anesthesia was found to significantly lower the corneal sensitivity but have little effect on IOP measurements. In ophthalmologic examination, topical anesthesia can be used to reduce corneal sensation without an effect on IOP.

Successful treatment of an unusually large corneal epithelial inclusion cyst using equine amniotic membrane in a dog.

A 10-year-old intact male Yorkshire Terrier was referred for investigation of a large raised and nonpainful corneal lesion oculus dexter. Clinical examination revealed a pale, translucent corneal mass, which occupied half of the corneal surface and measured 11 mm x 11 mm x 13 mm. The mass was removed by superficial keratectomy and equine amniotic membrane (AM) was transplanted into the large corneal defect to cover the wound and provide tectonic support for the remaining cornea. The mass was histologically confirmed as a corneal epithelial inclusion cyst. There was no evidence of recurrence or complication at the surgical site 100 days postoperatively. Corneal epithelial inclusion cysts are uncommon in dogs. Although superficial keratectomy is the recommended treatment for corneal inclusion cyst, the combination of superficial keratectomy and AM transplantation had to be considered as an alternative for repair of large corneal defects. This is the first case report of the combined application of AM and superficial keratectomy to successfully treat a corneal inclusion cyst in a dog.

Case Report: Surgical Treatment of Severe Facial Wounds and Proptosis in a Dog Due to a Traffic Accident.

Although facial wounds caused by traffic accidents in dogs are common, the surgical management of severe facial injuries involving the soft tissue, bone, dentition, nose and orbit are challenging. A 2 year-old Korean Jindo dog was diagnosed with severe skin defects of the face and proptosis caused by a vehicular accident. Along the left lateral maxilla, severe injury involving the overlying skin and platysma muscle occurred, to the extent that the middle part of the sphincter colli profundus pars intermedia muscle was exposed. Repair surgeries of the skin defects and globe displacement were performed using a local subdermal plexus rotation flap and a partial transposition of the dorsal rectus muscle combined with small intestinal submucosa (SIS) instead of enucleation as the first attempt. SIS was used to sustain the torn medial region. In this case, the surgery resulted in good cosmetic and functional outcome in the dog, despite the atypical complexities upon presentation.

Quantitative assessment of pupillary light reflex in normal and anesthetized dogs: a preliminary study.

The purpose of this study was to quantitatively assess the pupillary light reflex (PLR) in normal and anesthetized dogs using a pupillometer. Eleven dogs (20 eyes) of various breeds were included. PLRs were measured with a handheld pupillometer in dim light before and during anesthesia. Anesthesia was conducted with atropine, xylazine and ketamine. Parameters of pupillometry included neurological pupil index (NPi), pupil size, percent of change (%CH), latency (LAT), constriction velocity (CV), maximum constriction velocity (MCV) and dilation velocity (DV). NPi,%CH, CV and MCV were significantly decreased during anesthesia compared with the pre-anesthesia data. The results suggest that atropine-xylazine-ketamine combination anesthesia depresses the PLR. Additionally, this study demonstrates the feasibility of the use of a pupillometer in dogs.

IOP change undergoing anesthesia in rhesus macaques (Macaca mulatta) with laser-induced ocular hypertension.

The objective of the study was to examine changes of intraocular pressure (IOP) undergoing anesthesia in Rhesus Macaques (Macaca mulatta) with Laser-induced Ocular Hypertension. Twenty male rhesus macaques (hypertensive glaucoma eye in OD; normal eye in OS) between 6 and 20 years of age were used for the study. The monkeys were anesthetized with ketamine hydrochloride (10 mg/kg intramuscularly) and 1% isoflurane, and then IOP in both eyes was measured by a single investigator using a calibrated Tonopen(TM) applanation tonometer (Mentor, Norwell, MA, U.S.A.). The mean IOP with ketamine anesthesia was 36.70 ± 12.04 (right eye: OD) and 15.88 ± 2.84 (left eye: OS). The mean IOP with isoflurane anesthesia was 19.98 ± 6.67 (right eye: OD) and 15.32 ± 2.15 (left eye: OS). Undergoing isoflurane anesthesia, the IOP of OD was significantly decreased. Conclusively, careful examination of IOP is required to prevent unexpected contraindication on glaucoma patient with isoflurane anesthesia.