Impact of Facial Conformation on Canine Health: Corneal Ulceration

Concern has arisen in recent years that selection for extreme facial morphology in the domestic dog may be leading to an increased frequency of eye disorders. Corneal ulcers are a common and painful eye problem in domestic dogs that can lead to scarring and/or perforation of the cornea, potentially causing blindness. Exaggerated juvenile-like craniofacial conformations and wide eyes have been suspected as risk factors for corneal ulceration. This study aimed to quantify the relationship between corneal ulceration risk and conformational factors including relative eyelid aperture width, brachycephalic (short-muzzled) skull shape, the presence of a nasal fold (wrinkle), and exposed eye-white. A 14 month cross-sectional study of dogs entering a large UK based small animal referral hospital for both corneal ulcers and unrelated disorders was carried out. Dogs were classed as affected if they were diagnosed with a corneal ulcer using fluorescein dye while at the hospital (whether referred for this disorder or not), or if a previous diagnosis of corneal ulcer(s) was documented in the dogs’ histories. Of 700 dogs recruited, measured and clinically examined, 31 were affected by corneal ulcers. Most cases were male (71%), small breed dogs (mean± SE weight: 11.4±1.1 kg), with the most commonly diagnosed breed being the Pug. Dogs with nasal folds were nearly five times more likely to be affected by corneal ulcers than those without, and brachycephalic dogs (craniofacial ratio <0.5) were twenty times more likely to be affected than non-brachycephalic dogs. A 10% increase in relative eyelid aperture width more than tripled the ulcer risk. Exposed eye-white was associated with a nearly three times increased risk. The results demonstrate that artificially selecting for these facial characteristics greatly heightens the risk of corneal ulcers, and such selection should thus be discouraged to improve canine welfare

Bacterial contamination of slit lamps in veterinary ophthalmology

PURPOSE: Healthcare-associated infection (HAI) is a well-known problem in human medicine. The contamination of medical devices with pathogenic organisms is less studied in veterinary medicine. The purpose of this multicenter study was to evaluate the bacterial contamination of slit lamps throughout Europe and part of the United States. The efficacy of standard cleaning was additionally investigated. METHODS: Samples from adjustment wheels of slit lamps were taken by different veterinary ophthalmologists and submitted for culture (n = 29). The efficacy of cleaning protocols was evaluated by taking a second sample after routine cleaning (n = 29). Sensitivity testing was performed for pathogenic bacteria using the minimum inhibitory concentration (MIC) or disc diffusion (Kirby-Bauer) method. Statistical analysis was performed using Fisher's exact test. RESULTS: Seventeen of 29 slit lamps were contaminated before cleaning. The most frequently cultured bacteria were Staphylococcus spp. and coliform bacteria. Twelve of 29 slit lamps showed no bacterial growth before and after cleaning. There was a significant difference before and after cleaning (P = 0.0008), with only 4/29 contaminated samples after cleaning. CONCLUSION: Contamination with pathogenic bacterial species is frequent in slit lamps used by veterinary ophthalmologists. A risk of cross-contamination in clinical patients has to be considered. Routine cleaning reduces bacterial contamination significantly