Treating dry eye - a work in progress

Humphrey's ophthalmologist has initiated some treatment for dry eyes. Keratoconjunctivitis sicca (or keratitis sicca) is chronic, bilateral desiccation of the conjunctiva and cornea due to an inadequate tear film. Humphrey has typically shown low-normal tear production on the Schirmer tear test (STT), but his values were never quite low enough to warrant formal treatment. Even after his recent corneal ulcers, his STT is unclear.

Humphrey's delighted expression the moment he learned his ulcer was healed and the cone was off for good!

Nonetheless, his STT history suggests he may benefit from attempting to increase tear production, as well as adding artificial lubrication. For the past 10 days, he has received OptixCare with hyaluron lubricating gel in his eyes multiple times a day, and it gives him immediate relief. In fact, he signals discomfort every so often by trying to paw at his face, and immediately stops when the gel is administered.

The next intervention recommended is the introduction of topical cyclosporine or tacrolimus. Often taken orally or intravenously, cyclosporine is an immunosuppressant used to treat rheumatoid arthritis, psoriasis, Crohn's disease, nephrotic syndrome, and in organ transplants to prevent rejection. But in ophthalmology, it is used topically in drops or gel to stimulate tear production.  Fun fact: ophthalmologic cyclosporine was originally developed for use in dogs, then adapted for humans as Restasis. Tacrolimus is typically also used as an anti-rejection medication when prescribed orally, but in veterinary ophthalmology it is applied topically to stimulate tear production.

In humans, a preparation of 0.05% cyclosporine is sufficient to stimulate tear production for people who suffer from dry eyes, but the proportion is different for dogs. veterinary A product called Optimmune® is widely available (and inexpensive compared to the human preparation!) at 0.2%, but Humphrey's ophthalmologist is considering up to a 2% preparation. However, Humphrey discovered that small dogs who received 2% experienced suppression of systemic lymphoblastogenesis, but not with 0.2%, suggesting that a lower concentration might be safer for a fellow his size.

Humphrey's opthalmologist prescribed tacrolimus 0.02% in an olive oil suspension - and it has worked extremely effectively. Upon his first dose, his scleritis (inflammation/redness of the sclera or whites of the eye) resolved! He will continue on EDTA as well, to manage mineral deposits that arrive in his eyes.

By the middle of July, as predicted, Humphrey's corneal lesions seem to have resolved - the scar tissue seems to be mostly gone, and his vision is restored, even in the bright sun!

This is a fantastic resolution to a very long and difficult healthcare journey!