In 2022, for the first time in history, the French Bulldog was named the most popular dog breed! While there is no denying that these pups are insanely adorable, they unfortunately are predisposed to many conditions.
Usually when a dog comes to the veterinarian with a red, squinty eye, one of the main causes we will look for is a corneal ulcer, also known as a scratch to the cornea. In order to make this diagnosis a drop of fluorescein stain will be applied to each eye. If any part of the cornea fluoresces we know there is an area of compromise. Let’s dive deeper into the anatomy of the cornea to understand why this happens!
The cornea is the outermost part of the eyeball. It is made up of 4 different layers:
The outermost layer is called the epithelium This layer can regenerate when injured. This layer is hydrophobic (water repelling), and therefore, when stained with fluorescein will not fluoresce. (Negative fluorescein stain- no corneal ulcer)
The layer right under the epithelium is the stroma. This layer is hydrophilic (water-loving) and will absorb the stain, and fluoresce. (positive fluorescein stain- corneal ulcer present)
The layer under the stroma is Descemet’s membrane. This layer is also hydrophobic, and will not absorb the stain. This means that if there is a corneal ulcer that has penetrated all the layers of the stroma, the fluorescein stain will be negative. This is called a desmetocele, and can become an emergency requiring surgical repair of the cornea.
The last layer of the cornea is the endothelium. It is a single cell layer thick, and cannot regrow.
Corneal ulcers are painful, and can occur in any breed of dog. However, brachycephalic breeds, including Bulldogs, Pugs, and Shih Tzus, are more susceptible.
Brachycephalic breeds possess distinctive facial structures, characterized by shortened noses, wider heads, and prominent eyes. While these features contribute to their undeniable appeal, they also heighten their risk of corneal ulcers!
Brachycephalic breeds often have shallower eye sockets compared to other breeds. This anatomical trait leaves their eyes more exposed and vulnerable to potential injuries or foreign objects coming into contact with the cornea. Their large, protruding eyes are prone to accidental pokes, scratches, or trauma from various objects.
Due to this conformation, their globes are often too large for the eyelids to sufficiently cover them. This is why the most common place for a corneal ulcer at right at the center of the globe, right where the eyelids should touch.
These breeds may have reduced tear production or inadequate tear distribution due to their unique facial structure. This condition, known as keratoconjunctivitis sicca (KCS) or dry eye, can lead to dryness and irritation of the cornea, making it more susceptible to developing ulcers because the tears are one of the crucial components of keeping the cornea protected as a barrier from the outside world.
Detecting corneal ulcers in their early stages is crucial for successful treatment. Keep an eye out for the following signs:
1. Squinting or Excessive Blinking:
2. Redness or Bloodshot Appearance:
3. Discharge or Tearing:
4. Cloudiness or Opacity:
5. Pawing or Rubbing at the Eye:
If you suspect that your brachycephalic dog (or any breed, or species (cannot forget about our cats!) for that matter) may have a corneal ulcer, it is crucial to seek immediate veterinary attention. A thorough examination by a veterinarian will involve staining the cornea to determine the location, depth, and severity of the ulcer, and likely other tests including one for tear production, as well as testing the intraocular pressure. Prompt treatment can help prevent complications and promote faster healing. Remember these conditions are painful, and the faster they are treated, so sooner they will be feeling better.