New research from the Royal Veterinary College (RVC) has revealed that flat-faced dogs and spaniels, amongst others, are more prone to keratoconjunctivitis sicca (KCS), aka ‘dry eye’.

The study1 was led by the RVC’s VetCompass Programme and is the largest study using anonymised veterinary health records to explore dry eye in dogs. The study included 363,898 dogs that were followed for a year to identify 1,456 dogs affected with dry eye.

The study found that one in every 250 dogs overall is affected by the condition, but certain breeds are especially prone.

The worst affected breeds were: American Cocker Spaniel (5.90%), West Highland White Terrier (2.21%), Cavalier King Charles Spaniel (1.91), Lhasa Apso (1.86%), English Bulldog (1.82%), English Bull Terrier (1.65%,) and English Cocker Spaniel (1.60%).

Other findings included:

  • Twenty-two breeds showed increased risk of dry eye compared with crossbred dogs including: American cocker spaniel (x 52.33), English Bulldog (x 37.95), Pug (x 22.09), Lhasa Apso (x 21.58) and Cavalier King Charles Spaniel (x 19.79).
  • Two breeds showed reduced risk of dry eye compared with crossbred dogs: Labrador Retriever (x 0.23) and Border Collie (x 0.30).
  • Brachycephalic breeds had 3.63 times the risk of dry eye compared with mesocephalic breeds.
  • Spaniel breeds had 3.03 times the risk of dry eye compared with non-spaniel breeds.
  • Breeds with bodyweight at or above the mean for their breed and sex had 1.25 times the risk of dry eye compared with dogs weighing below the mean for their breed and sex.
  • Dogs in lower bodyweight groups had higher risk of dry eye: dogs weighing 10.0 - < 20.0 kg had 5.49 times the risk compared with dogs weighing 30.0 - < 40.0 kg.
  • Dogs aged ≥ 12 years had the highest risk of dry eye (x 29.44) compared with dogs < 3.

The authors of the study have recommended that vets help reduce the frequency and impact of KCS by testing for the adequacy of tear production as part of the annual physical examination of all dogs but especially for the list of predisposed breeds as they approach advanced age.

Dr Dan O’Neill, Senior Lecturer, Companion Animal Epidemiology, at the RVC, and author of the paper, said: "We all love those glossy puppy dog eyes, but this study shows that sadly not every dog enjoys good eye health. This research identifies that flattened faces in some breeds makes these breeds more prone to this painful dry eye condition. Work is urgently going on to improve the health of many of these flat-faced breeds, but in the meantime the message from everyone who cares about dogs is to ‘stop and think before buying a flat-faced dog."

Rick Sanchez, European Specialist in Veterinary Ophthalmology says: "Taking a fresh dip into an old, dull looking disease like KCS has shown us there is more for us to learn than we thought. Ultimately, all of us, clinicians, nurses, researchers, breeders and dog owners are, in one form or another, care givers for our beloved animals. All of us need whatever new information we can set our eyes on to inform our next steps in improving canine ocular health. There’s no better eye opener than evidence-based scientific findings. I hope this research helps all of us raise awareness about canine KCS and that it helps us keep those animal eyes looking fresh and healthy, as they should.”

Bill Lambert, Health, Welfare and Breeder Services Executive at The Kennel Club commented: "These findings are important to help us to identify which dogs are most at risk of developing dry eye. Ultimately, this should help owners that may need support in spotting the initial signs, as well as ways to treat affected dogs and how to prevent it occurring in the future. The data from this fascinating research will also be used to collaboratively create strategies to tackle health priorities with the breed clubs of affected breeds."


  1. O’Neill et al. (2021) “Keratoconjunctivitis sicca in dogs under primary veterinary care in the UK: an epidemiological study” Journal of Small Animal Practice. The full paper can be accessed here:

Photo: Cavalier King Charles Spaniel with KCS. By Rick F Sanchez BSciBiol DVM DipECVO CertVetEd FHEA.JPG

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