Louie: Vision Restoring Surgery for Absolute Keratoconjunctivitis sicca.

 

By: Audrey Pierson, DVM, DACVO

Signalment:

10yr Mn Miniature Poodle

History:

In June 2022, sweet Louie was found by a canine rescue organization and noticed to have crusted scabs across both eyes.
Examination by their primary veterinarian yielded topical
mediations to prevent infection and referral to GCVS Ophthalmology.

GCVS Ophtahlmology:

Louie was seen by GCVS Ophthalmology and diagnosed with absolute keratoconjunctivitis
sicca (KCS), or extreme dry eye.

The pre-corneal tear film is essential to maintaining health of the cornea. The cornea is
avascular and requires it’s nutrition from the tear film and the aqueous humor. Absolute dry eye
is diagnosed by a tear function of 0mm of wicking action in 60 seconds. (Normal is 20mm in 60
seconds.) Absolute dry eye is rare and is typically seen with severe damage to the lacrimal
glands or congenital deformities where the tear, or lacrimal gland, fails to form correctly.

At Louie’s recheck 3 weeks later, he had developed secondary entropion due to his dry eyes.
When attempting to blink, his eyelid margins would not effectively cross his corneal surface.
Instead, they would become adhered to his cornea due to the dryness, and roll inwards rather
than blink. While we usually attempt to allow tear stimulants at least 6-8 weeks to prove
efficacy, given Louie’s extreme discomfort and lack of any response, we elected to move
forward with surgical therapy for absolute KCS.

Surgical treatment for absolute KCS is a parotid duct transposition (PDT). A PDT reroutes the
salivary duct of the parotid gland to the inferior conjunctival fornix. When stimulated, the gland
produces “saliva” which coats the ocular surface. Unfortunately, saliva is not the same
composition as tear film. Therefore, some patients actually can find their saliva irritating.
However, in patients with painful eyes with minimal vision, PDT offers a solution for comfort
and possible vision.

In addition to Louie’s PDT, we also wanted to address his entropion. We felt his entropion was
secondary to severe dry eye. Therefore, we attempted to avoid eyelid reconstruction involving
surgically removing part of his eyelids. We performed hyaluronate injections. This material is
injected in to the eyelid margin and will remain as fillers in the eyelid margin for 6-9 months. We
hoped this would give Louie time to have normal eyelid excursions across a moist cornea. With
time, the goal is that his entropion would self-correct with the healthier tear film and ocular
surface.

By 1 week post-operatively, Louie was already more comfortable and was producing “tears”
(saliva.) Thankfully, his ocular surface thought he was producing tears and became happier.
The scarring, inflammation, and discomfort improved. Additionally, his entropion was
temporarily resolved. The rescue group noted a significant improvement in his activity level and
demeanor.

Louie has done very well following his bilateral PDT. He is much happier, can see well, has a
strong blink function, and moist corneal surfaces. While his ocular tear film is still lacking, the
presence of saliva provides enough lubrication to keep his eyes functioning.

Unfortunately, Louie was concurrently diagnosed with an insulinoma after pre-anesthetic lab
work revealed chronically elevated glucose. Therefore, at the time of his PDT surgery, he had a
pancreatic mass removed. While prognosis for life regarding his abdominal neoplasia is
guarded, he is able to live out his remaining months comfortable and visual. We continue to
root for Louie and love seeing him back at his ophthalmic rechecks. He holds a very special
place in our hearts.