The Key Points of Dry Eye Disease or Keratoconjunctivitis Sicca

Today we'll be presenting the key points of one of the most common ocular diseases in dogs: Dry Eye Disease or Keratoconjunctivitis Sicca.

Keratoconjunctivitis Sicca is an ocular surface (cornea and conjunctiva) inflammatory disease secondary to at least one of the tear film phases deficiency that causes tear hyperosmolarity. This hyperosmolarity and increased friction will lead to secondary infections, dehydration and malnutrition of the cornea and conjunctiva and to an increased probability of corneal ulcerations. Chronic inflammation of the ocular surface will also end up generating conjunctival hyperaemia, hyperkeratinization and thickening of the corneal epithelium, corneal vascularization with increased migration of inflammatory cells and the corneal deposition of pigment, lipids, and calcium. The prognosis is usually favourable, although it will depend on the cause and whether an early effective and individualized treatment is implemented.

There are two major classifications of Keratoconjunctivitis Sicca:

  • Qualitative: Pathological decrease of the lipid or mucoid components of the tear film. In this case, the lacrimal gland is functional and the tear hyperosmolarity is due to an increase in its evaporation rate. The cause can be an acute/chronic damage or inflammation of the Meibomian glands and/or the conjunctiva goblet cells, such as in cases of infectious blepharitis, seborrheic dermatitis, etc.
  • Quantitative: Pathological decrease of the aqueous component of the tear film. In this case, hyperosmolarity is due to reduced secretion of the aqueous component under normal evaporation conditions. This is the most common initial presentation in dogs, although in most cases, a vicious circle is generated in which the other types of components of the tear film are also affected in the end.
Quantitative Keratoconjunctivitis Sicca causes are varied, such as infectious diseases, endocrine diseases, systemic immune-mediated/autoimmune diseases, iatrogenic (surgical), etc. although the most common is a localized and chronic immune-mediated inflammation of the lacrimal gland (immune-mediated adenitis). There are dog and cat breeds that are more predisposed, as we already mentioned in one of our previous posts in our social networks (Instagram, Linkedin), such as brachiocephalic breeds, West Highland White Terrier, Cocker Spaniel and American, etc.

The symptoms that may occur are: very characteristic mucous exudate, conjunctival hyperaemia, opaque cornea with neovascularization, oedema and corneal ulceration, etc.

To reach its diagnosis, we will have to look at the patient’s clinical history, to perform a general and ophthalmoscopic examination, if we suspect of systemic pathologies also some blood test and/or other complementary tests, and of course some specific ophthalmological tests: Shirmer Test, Fluorescein Stain, Lissamine Green Stain, TBUT (Tear Break-up Time), Impression Cytology and Osavet Test.

There are several types of systemic and topical medical treatments such as replacement tears (there is a great variety), topical immunosuppressants, etc. and in most of the cases, they will be prescribed at the same time. In addition, if there are secondary problems such as corneal infections or ulcers, they will also have to be treated. There are also surgical procedures such as transposition of the parathyroid duct, among others.

Another essential asset to help improve Keratoconjunctivitis Sicca symptoms, with proven efficacy in dogs, will be the supplementation with specific nutraceuticals such as Lacrimalis, rich in Omega-3 Fatty Acids that will improve tear quality, stability and its secretion, Lactoferrin with anti-inflammatory and antimicrobial properties on the ocular surface and antioxidants such as Vitamins E and C and the minerals Zinc and Copper.

Dr+Vet Pet Care by Böthmen Pharma, will be presenting each one of the different ophthalmological tests that we have mentioned in this article during the following weeks in association with Instituto Veterinario Oftalmológico (IVO) so you can learn more about them, stay tuned for more information!

Why some dog breeds are more predisposed to develop ocular pathologies?

In the recent months, and especially after Danika Bannasch et al.’s publishment in December in the journal Canine Medicine and Genetics, inbreeding in canine breeds has become lately the main topic in the animal health media. Inbreeding means having a high kinship between one and/or different specimens. You may be wondering the relationship between this study and the predisposition of some canine breeds to develop ocular pathologies, right? Keep reading to get to know how these two matters are related.

Unlike production animals, breed dogs are selected based on their pedigree and phenotypic characters or physical appearance. The pedigree or genealogical tree is insufficient as it does not include a significant number of individuals; while being selected according to the characters or the appearance traits, ends up having an impact on the animal’s functional and/or vital characteristics. The Bannash et al. study, using the Wisdom Health Genetics database, estimated an inbreeding average of 25% in 227 breeds. A high inbreeding is significant to develop certain diseases. In addition to the inbreeding problem, the pet’s life quality has improved, which implies that, as in humans, developing degenerative problems associated to age.

Some breeds-disease associations are well known, such as hip dysplasia in Golden Retrievers or heart failure in brachiocephalic. Even so, we always forget about those that concern the sight, which besides of being extremely annoying, they can end up having huge repercussions on the animal's health. That is why the last month we made several publications on our social media (LinkedIn and Instagram) presenting our ophthalmological line related to canines (and felines, less frequent) predisposed to develop ophthalmological pathologies. We have relied on the BVA (British Veterinary Association) and The Kennel Club study . Please find forward the links to get to know the predisposed breeds to each disease:

Age related or genetically predisposed degenerations have a reduced treatment option. Supportive treatments that slow the onset and/or relieve symptoms are often the only solution. PREVENTION IS THE KEY.

Please find forward the following link if you want to check out the diseases, regardless the ophthalmic ones, that is predisposed to develop each dog breed.