05 May 2021
The importance of eye testing in brachycephalic breeds
Professor Sheila Crispin, Past President of the Royal College of Veterinary Surgeons, discusses brachycephalic dogs and the importance of eye testing them.
Why eye test?
The value of clinical examination of the eye as a means of identifying inherited eye conditions has long been recognised. The British Veterinary Association/Kennel Club/International Sheep Dog Society (BVA/KC/ISDS) Eye Scheme has been in existence for more than 50 years and the aims of the Eye Scheme are simple; to identify inherited eye disease before the dog is used for breeding, with further monitoring during the dog’s life and a final check when the dog is over 8 years of age so that late onset inherited diseases are not missed and accurate information is collected over time. Known inherited diseases of the eye are listed under Schedule A (406 KB PDF) of the Eye Scheme and the BVA’s Hereditary Eye Disease Leaflet ( provides further information about hereditary and breed-related conditions.
But what of those breed-related ocular conditions where the mode of inheritance may be unknown, but the negative effects on the individual dog are clearly visible? Understanding the welfare implications of inherited disease and breed-related ocular disorders is crucial and those conditions that may be a cause of pain or blindness, require surgical correction, or lifelong medical therapy should be regarded as priorities for elimination, as they have substantial effects on the individual’s quality of life. Sadly, many brachycephalic dogs have serious quality of life issues and not just related to eyes; those connected with respiratory problems top the list.
The number of non-Schedule A brachycephalic dogs tested under the Eye Scheme is depressingly low, rarely reaching double figures for the entire breed over the course of a year. By way of example, no Brussels Griffons, Chihuahuas or Neapolitan Mastiffs were examined under the Eye Scheme in 2014, 2015 and 2016, whereas reasonable numbers of brachycephalic breeds that are on Schedule A, such as the Boston Terrier, Cavalier King Charles Spaniel and Rottweiler, were presented for examination.
What are brachycephalic dogs?
Brachycephaly includes all those breeds, both pure and crossbreed, in which the face is foreshortened because of the underlying skull conformation, with a ‘short head’ in consequence. Table 1 includes some examples of brachycephalic breeds).
Table 1 ‘Brachycephalic’ Breeds – some examples
|Small dogs: less than 10kg||Medium to large dogs over 10kg|
|Brussels Griffon||Bull Mastiff|
|Cavalier King Charles spaniel||Cane Corso|
|French Bulldog||Dogue de Bordeaux|
|Japanese Chin||English Mastiff|
|King Charles Spaniel||Neapolitan Mastiff|
|Lhasa Apso||St Bernard|
In small dogs the result is a flat, somewhat baby-faced, appearance with prominent eyes, excessive wrinkling of the skin, nasal skin folds that may directly contact the eye, inversion of the inner aspect of the lid (medial lower eyelid entropion) and lids that may not met when the dog blinks - below.
In larger breeds the predominant features are often excessive wrinkling of the skin, nasal skin folds that may directly contact the eye and poor eyelid anatomy so that the lids are inverted (entropion), or everted (ectropion), or there are combinations of both resulting in a so-called ‘diamond eye’ - below.
In these dogs, too, the ability to blink effectively may be compromised. The secondary ocular problems related to brachycephaly can be substantial and commonly involve the cornea (e.g. exposure keratopathy, corneal pigmentation and corneal ulceration), as well as tear film distribution and drainage (e.g. exposure keratopathy, tear overflow and tear staining). The extent to which the health of the cornea is affected is not always recognised, especially as corneal sensitivity is often reduced in brachycephalic dogs. Areas of corneal drying (exposure keratopathy) as a consequence of prominent eyes and/or inadequate tear film distribution make these dogs more susceptible to corneal ulceration and all ulcers in brachycephalic dogs are serious. Failure to recognise the severity of the ulcer can lead to loss of the eye.
Why eye test brachycephalic dogs?
Clearly, if two brachycephalic dogs are bred from they will produce puppies with the conformational characteristics of the parents. The fact that the precise mode of inheritance of those multifactorial characteristics is not fully understood is almost irrelevant; the fact that the abnormalities associated with brachycephaly can have a serious impact on the dog’s health for all of its life is highly relevant. Eye testing of brachycephalic dogs before they are used for breeding is essential if we, especially the veterinary profession, are committed to improving matters, including providing breeders with clear and unequivocal advice about the welfare implications of brachycephaly; advice that will include moderation of facial characteristics, rather than exaggeration.
Examination of brachycephalic dogs under the Eye Scheme is one way of achieving a better future for these dogs. To a considerable extent, the main driver for improvement will come from conscientious breeders who use the Canine Health Schemes, as well as concerned and increasingly well-informed people who are considering buying a puppy. Ideally, it is the prospective owners who will ask if the parents have been health tested and it is they who will not accept any gross exaggerations that result in clinical problems and large veterinary bills. By working together we can give these dogs a healthier life.
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