Diabetes mellitus affects thousands of dogs every year and can cause nerve damage (peripheral neuropathy) that may lead to impaired vision, in particular corneal disease due to decreased corneal sensitivity, tear production and tear film stability. Blindness resulting from cataracts is the most common eye complication of canine diabetes, and surgery is usually performed to restore vision. However, if corneal disease is present, surgery may not be possible. Also, if cataract surgery is successfully done and corneal disease develops afterward, it could lead to loss of or decreased vision. Current treatments have not been proven to restore corneal sensitivity or tear-film stability in diabetic dogs.
Recently, topical naltrexone, a commercially available opioid antagonist, was shown to restore corneal sensation, reverse the adverse tear-film effects of diabetes and improve corneal wound repair in other species. Researchers will evaluate the effectiveness of naltrexone in increasing corneal sensitivity, tear production and tear-film break-up time in diabetic dogs. If proven efficient, topical naltrexone could be used to improve the quality of vision and decrease suffering due to corneal disease in diabetic dogs.