Think Before You Reach for That Eye Ointment: New Study Highlights Rising Antibiotic Resistance in Veterinary Ophthalmology

A new study published in Veterinary Ophthalmology is sending an important message to veterinarians: antibiotic resistance isn't just a concern for injectable and oral medications. It is becoming an increasingly important issue with topical ophthalmic antibiotics used to treat eye disease in dogs, cats, and horses.

Researchers evaluated antimicrobial resistance patterns to commonly prescribed eye medications and found growing evidence that resistant bacteria are becoming more common. According to study co-author Dr. Lionel Sebbag, DVM, PhD, DACVO, a veterinary ophthalmologist at the Hebrew University of Jerusalem, the problem has become much more noticeable over the past decade.

"Five years ago, antimicrobial resistance was rarely discussed at ophthalmology meetings," Sebbag noted. "Now it's a major topic."

Not Every Red Eye Needs Antibiotics

One of the biggest mistakes veterinarians can make, Sebbag says, is assuming every red eye has a bacterial infection.

"Redness is a clinical sign, not a diagnosis."

Many common eye conditions—including allergies, dry eye, glaucoma, uveitis, eyelid disorders, and immune-mediated diseases—do not benefit from antibiotics. In these cases, repeatedly switching from one antibiotic to another simply delays the correct diagnosis while contributing to antimicrobial resistance.

Sebbag offers a simple piece of advice that every veterinarian and veterinary student should remember:

"If the eye isn't getting better, don't change the antibiotic. Change the diagnosis."

Culture Early, Treat Smarter

The study reinforces the importance of antimicrobial stewardship in veterinary ophthalmology.

Rather than prescribing broad-spectrum antibiotics empirically for every corneal ulcer, veterinarians should consider obtaining cytology, bacterial culture, and susceptibility testing whenever infection appears significant, particularly if ulcers are deep, rapidly progressing, melting, or failing initial therapy.

Just as in internal medicine, fluoroquinolones should not automatically become first-line therapy simply because they are broad spectrum. Reserving these drugs for cases where culture results indicate they are necessary helps preserve their effectiveness for future patients.

For routine cases, Sebbag often begins treatment with narrower-spectrum topical antibiotics and adjusts therapy once culture results become available.

Exciting Antibiotic-Sparing Therapies

Perhaps the most exciting part of the discussion involves treatments that may eventually reduce our dependence on antibiotics altogether.

Several emerging therapies can reduce bacterial numbers without using traditional antibiotics, including:

• Photoactivated chromophore therapy (PACK-CXL), which combines riboflavin and ultraviolet light to destroy bacteria on the corneal surface.

• UV-C light therapy, another technology showing promise against infectious organisms.

• Antiseptic eye medications, including povidone-iodine, hypochlorous acid, and chlorhexidine formulations that are already available in parts of Europe and other countries.

While many of these treatments are not yet widely available in the United States, they represent a growing area of research that may help preserve antibiotic effectiveness in the future.

Stewardship Starts in General Practice

The study emphasizes that antimicrobial stewardship begins long before a patient reaches a specialist. Every veterinarian who prescribes an ophthalmic antibiotic has an opportunity to reduce unnecessary antimicrobial exposure through careful diagnosis, appropriate diagnostics, and thoughtful drug selection.

Sebbag also believes veterinary schools should place greater emphasis on antimicrobial stewardship and ocular microbiology so that new graduates enter practice prepared to make evidence-based prescribing decisions.

A Team Effort

The authors stress that solving antibiotic resistance will require collaboration between veterinary ophthalmologists, microbiologists, pharmacologists, and general practitioners. Together, these groups can develop clearer guidelines for interpreting culture results, selecting appropriate medications, and preserving the effectiveness of existing antibiotics.

As antibiotic resistance continues to grow across both human and veterinary medicine, the message is becoming increasingly clear: good medicine starts with the correct diagnosis, not simply the next antibiotic.