Clinical Study

Introduction/Purpose

Tear staining is a common, unsightly finding in many light-coated dogs. While this is often regarded as a benign cosmetic abnormality, owners often desire treatment and resolution of this discoloration.

Options to correct this abnormality should first include addressing a possible underlying cause, such as eyelid abnormalities, abnormal periocular hairs or cilia, conjunctivitis, and/or nasolacrimal obstructions. Once a thorough ocular exam has been performed and any abnormalities addressed, the residual periocular wetting and staining can be addressed in a combination of methods.

Most importantly, proper hygiene can best be maintained by keeping the periocular hair clipped short, clean, and dry. If staining is still a problem, it can be addressed with supplemental oral medications.

Tylosin, a macrolide antibiotic, has been used in several oral preparations to help reduce or eliminate this discoloration. This medication is thought to bind/neutralize naturally occurring, organic compounds found in tears called porphyrins. While the exact mechanism of action remains unknown, it does appear to successfully reduce or eliminate tear staining, often within 4-6 weeks.

The purpose of this pilot study was to test the palatability and compliance of an oral chewable vehicle (“treat”) and determine an appropriate dosage for dogs.

study-chart single-bottle-ess300

Methods and Materials

Dogs

Thirteen dogs of different breeds were selected to be included in the study. Represented breeds included Bichon Frise (3), Toy Poodle (3), Maltese (1), Shih Tzu (1), and mixed breed (5). The average age of the dogs was 4.75 years and included one intact female, three intact males, four neutered females, and five neutered males.

To be included in the study, dogs had to fit the following criteria: 1) have evidence of tear staining, 2) not be under any treatment for tear staining either at the time of or within 2 months prior, and 3) be otherwise healthy with no known evidence of systemic disease.

Screening/Monitoring

At enrollment, all dogs received complete physical and ophthalmic examinations, which included slit-lamp biomicroscopy and indirect ophthalmoscopy; all dogs were found free of gross systemic and ophthalmic diseases. Schirmer tear tests (STT) were obtained and fluorescein dye was applied. All dogs were weighed to obtain a proper dosage schedule. Photographs were taken (front, right-sided face, and left-sided face) and the stained periocular hair was clipped.

Owners were instructed to give the trial “treat/medication” daily based on the pet’s weight and asked to maintain a daily log. Dogs weighing less than 9 lbs were given a 150mg tylosin chew once daily; those greater than 9 lbs were given a 300mg tylosin chew once daily. This log included a daily improvement score (0-4; 0-no improvement, 1-25% improvement; 2-50% improvement; 3-75% improvement; and 4-100% improvement), confirmation that medications were given, and asked owners to note any daily abnormalities such as in appetence, diarrhea, vomiting, etc.

Patients were rechecked approximately thirty and sixty days after starting the “treat/medication”. At both recheck visits, the log information from the previous 30-days was collected. At the 30-day recheck, an ophthalmic exam was performed and photographs taken. At the 60-day recheck, the ophthalmic exam included a STT and corneal fluorescein stain and photographs were again collected.

Conclusions:

Overall, 12 out of 13 dogs responded very well to the tear treat supplement; this was supported by owner’s observations and ophthalmic exam.

In general, the “OcuBright Tear Treat” was well accepted by clients and showed beneficial and impressive results in 12/13 dogs. It appears to be a safe product with no significant abnormalities noted.

Larger dogs may require a larger dosage. Larger future clinical studies are warranted; a more complete evaluation of serology and tear components may be beneficial.

Robert Swinger