The investigation into an apparent increase in severe, sudden bilateral dry eye in dogs has taken a new turn, after extensive testing of recalled Years dog food failed to identify a contaminant or other safety issue.
Years voluntarily recalled its Fresh Meals in August following reports of dogs developing an unusual form of acute bilateral keratoconjunctivitis sicca (KCS), often with profoundly reduced or absent tear production.
The company initially investigated possible contamination within its buckwheat supply. However, results published on 22 September say 21,757 individual tests covering 1,129 substances found no evidence of contamination, toxins, packaging migration, manufacturing problems or another food-safety issue.
Buckwheat testing draws a blank
Every batch of buckwheat historically used by Years was included in the investigation.
According to the report, buckwheat was tested for 940 different substances, including tropane alkaloids, mycotoxins, pesticides, heavy metals and fagopyrin. No toxin, contamination or safety issue was identified.
The investigation also included 273 retained or customer-returned meals containing buckwheat, and Years says affected cases were not concentrated around a particular buckwheat batch, cooking cycle or production batch.
Years says it has therefore found no evidence linking its food to the cases and the source of the apparent increase in severe bilateral KCS remains unexplained.
Cases identified in dogs that never ate Years
The report also contains new case information which suggests the clinical problem extends beyond dogs eating the recalled food.
Years says case data provided by the British Association of Veterinary Ophthalmologists (BrAVO) has identified 155 UK cases in dogs fed Years and 41 in dogs that had never eaten the brand.
Those figures are not directly comparable with the 192 potential eye problems previously reported to Years by customers, which had not at that stage been clinically verified.
A further 55 cases have been reported by veterinary ophthalmologists in Finland and Hungary, where Years food is not sold. The Years report gives figures of 25 cases identified by two ophthalmologists in Finland and approximately 30 in Hungary, although it cautions that the Hungarian figure has been assembled from fragmented reports rather than a coordinated national surveillance system.
This adds weight to ophthalmologists’ earlier warnings not to define suspected cases according to diet alone.
Is buckwheat still under suspicion?
There is one intriguing finding that remains unresolved.
Years reports that foods containing buckwheat appeared in the diets of a number of affected dogs in Finland and Hungary at a prevalence it says was greater than buckwheat’s overall market share.
But the company is careful to state that this does not establish correlation or causation. Figures showing how many affected dogs in the UK, Finland and Hungary were eating diets without buckwheat have not yet been published. Environmental exposures, medication and seasonal factors are among the other possibilities that still need investigation.
Years nevertheless plans to remove buckwheat from its recipes when it resumes deliveries in October, which it says is both precautionary and in response to customer preference.
Wider KCS investigation continues
The Years investigation may have finished, but the wider veterinary investigation has not.
BrAVO has been gathering information from vets about dogs developing acute bilateral KCS regardless of feeding history. Earlier this month, the organisation stressed that there was insufficient evidence to link the apparent increase in cases to Years products or any specific dietary component.
Further work is also planned. Years says it will collect treatment outcomes and share them with BrAVO, and is funding an independent study led by veterinary ophthalmologist David Williams at the Queen’s Veterinary School Hospital, Cambridge. That work will use histopathology to examine lacrimal tissue from affected dogs in the hope of finding clues to the underlying disease process.
For vets, the practical message therefore remains much the same: look for the unusually acute, bilateral and severely tear-deficient presentation, treat the ocular disease promptly, and report relevant cases regardless of what the dog eats.
For more detailed guidance on assessment, treatment, monitoring and referral, read our Years dog food and dry eye: what should vets do with suspected cases? article.
