Corneal abrasion and microbial contamination in horses following general anaesthesia for non-ocular surgery.

The research focuses on determining the incidence of corneal abrasions and microbial contamination in horses that undergo general anaesthesia for non-eye surgeries. It was found that some instances of corneal abrasions occurred, with a certain bacteria species being frequently isolated from the eye samples. This outcome is similar to previous findings in research involving dogs.

Methodology

• The study is a prospective, observational, clinical research involving 40 client-owned horses that were scheduled for elective non-eye surgeries.
• The researchers took conjunctival sac swabs, applied fluorescein dye, and recorded digital images from the eyes of the horses after the pre-anaesthetic medication and 24 hours after recovery from general anaesthesia.
• An ophthalmic ointment, based on paraffin, was applied to the ocular surface intraoperatively following the collection of a sample in a sterile container.
• All samples were cultured for aerobic, anaerobic, and fungal organisms.
• Data on subjects’ demographics, the chronology of the use of the ointment, the duration of anaesthesia, recumbency after and during surgery and recovery, and results for fluorescein uptake and culture were recorded.

Results

• Complete data were collected from 34 horses out of the initial 40. Six of these horses, equivalent to 17.6%, developed mild unilateral generalized fluorescein uptake in line with corneal abrasions.
• Recumbency on the operating table was found to be the only significant risk factor related to corneal abrasions.
• In total, 11 bacterial species were identified in the samples, with Staphylococcus spp. (15 eyes) and Micrococcus spp. (eight eyes) being the most frequently isolated bacteria.
• Two fungal species (Aspergillus spp., Saccharomyces spp.) were isolated postoperatively in two eyes.
• Contamination of the ointment was recorded in two cases, representing 5%, but cross-contamination was ruled out.

Conclusion

• The study concluded that the incidence of corneal abrasion and ulceration in horses undergoing general anaesthesia, and the contamination rate of ophthalmic solutions are similar to those previously reported in studies involving dogs.