Study links weather and enucleation risk in equine corneal ulcers
Bottom line
Corneal ulceration in horses may be shaped not just by trauma and infection, but by the environment around the horse. In a retrospective study of 420 equine cases seen from 2020 to 2023 in the Western United States, researchers found that higher wind speed and temperature were associated with corneal ulceration, while older age, deeper ulcers, concurrent uveitis, and left-eye involvement were linked with a greater likelihood of enucleation. The paper adds population-level data to a condition equine veterinarians already recognize as urgent, painful, and potentially vision-threatening. (aaep.org)
Why it matters: For veterinary professionals, the study helps sharpen both prevention and triage. Horses are already considered vulnerable to ocular trauma because of the size and lateral placement of their eyes, and standard references note that complicated or deep ulcers can progress quickly to surgery or loss of the globe. By tying ulcer presentation to environmental conditions and identifying factors associated with enucleation, the new report may help clinicians counsel pet parents on seasonal or weather-related risk, prioritize aggressive management in older horses or those with deep ulcers and uveitis, and think earlier about referral when prognosis worsens. Prior work in Colorado also linked environmental variables, including wind speed, to equine ulcerative keratitis, which supports the plausibility of the new findings. (aaep.org)
What to watch: Whether the findings are validated in other regions, and whether they change how equine practices approach prevention messaging, referral timing, and monitoring during hot, windy periods. (beva.onlinelibrary.wiley.com)
Key facts
- Study type
- Retrospective study
- Sample size
- 420 horses
- Study period
- 2020 to 2023
- Region
- Western United States
- Associated with corneal ulceration
- Higher wind speed and temperature
- Associated with enucleation
- Older age, deeper ulcers, concurrent uveitis, and left-eye involvement
- Clinical context
- Corneal ulceration is an ophthalmic emergency with risk of infection, perforation, and vision loss
A new retrospective study of 420 horses with corneal ulceration, covering cases from 2020 through 2023 in the Western United States, points to weather as part of the risk picture. According to the study abstract, higher wind speed and temperature were associated with corneal ulceration, while increased age, deeper ulcers, uveitis, and left-eye involvement were associated with the need for enucleation. The findings add a broader epidemiologic layer to a condition that equine clinicians already treat as an ophthalmic emergency because of the risk of infection, perforation, and loss of vision. (merckvetmanual.com)
That matters because corneal ulceration in horses is usually discussed first as a trauma-and-infection problem. AAEP notes that horses are especially prone to eye injury because their eyes are large and laterally positioned, leaving the cornea exposed to environmental insults. Merck’s emergency guidance likewise emphasizes that complicated ulcers can require intensive topical therapy, antifungals in appropriate cases, and referral to clinicians with advanced ophthalmology training when surgical stabilization may be needed. (aaep.org)
The new study’s environmental signal is also consistent with earlier regional research. A Colorado retrospective study on equine ulcerative keratomycosis found associations with environmental factors including wind speed, suggesting that climate and local conditions may influence not only whether ulcers develop, but also what kind of corneal disease follows. That doesn’t prove causation in the new 420-case series, but it does strengthen the idea that weather exposure deserves more attention in equine eye-risk assessments, especially in dry or windy areas of the West. (beva.onlinelibrary.wiley.com)
On outcomes, the reported enucleation-associated factors are clinically intuitive, but still useful to see grouped together. Older horses, deeper ulcers, and concurrent uveitis all fit with a more guarded prognosis, and prior equine ophthalmology literature has shown that severe ulcerative disease can end in surgery or globe loss despite treatment. In one hospitalized equine ocular-disease cohort, 12% of horses underwent enucleation, while older reports on severe corneal perforation and iris prolapse also documented enucleation in a subset of cases. (onlinelibrary.wiley.com)
I wasn’t able to find a separate press release or a published outside expert reaction specifically addressing this study. What is available from professional and reference sources, however, lines up with the paper’s practical implications: nonhealing, deep, or “melting” ulcers need prompt escalation, and fungal involvement remains a major concern in horses. AAEP educational material and Merck both stress early diagnosis, close monitoring, and rapid intervention when ulcers are severe or not responding. (aaep.org)
Why it matters: For equine veterinarians, this study could be most useful at the intersection of case management and client communication. If hot, windy conditions are associated with more ulcer cases, practices in the Western United States may want to reinforce prevention steps during higher-risk periods, such as closer observation of horses with ocular irritation, quicker workups for blepharospasm or discharge, and discussion of environmental management where feasible. On the treatment side, the enucleation-linked variables may help frame prognosis earlier, especially when an older horse presents with a deep ulcer and uveitis. (aaep.org)
The left-eye finding is more intriguing than immediately actionable. Without full-text access, it’s hard to know whether that association reflects handling patterns, turnout environments, referral bias, or a statistical artifact. So that detail is best treated as hypothesis-generating rather than practice-changing until the full methodology and multivariable analysis can be reviewed. This is an inference based on the limited abstract-level information available. (onlinelibrary.wiley.com)
What to watch: The next step is whether the full paper, or follow-on studies, clarify effect sizes, seasonal patterns, microbiology, and whether these associations hold outside the Western United States. If they do, veterinarians may have stronger evidence to support weather-linked prevention advice and earlier referral thresholds for horses with the highest-risk ulcer profiles. (beva.onlinelibrary.wiley.com)