Mastering corneal ulcers (part 2)

Joshua Broadwater, DVM, DACVO, veterinary ophthalmologist at the Charlotte Animal Referral & Emergency in North Carolina, highlighted the importance of understanding normal corneal anatomy before addressing abnormalities like corneal ulcers during his session at the Fetch dvm360 conference in Charlotte, North Carolina.¹ In part 1 of this article, he outlined how corneal ulcers occur, including inadequate tear production, trauma, and foreign objects, which could potentially lead to an infection. Broadwater advised a thorough examination to identify underlying pathologies contributing to ulcers but cautioned veterinary professionals with diagnostics if the ulcer is especially deep.

Now that a corneal ulcer is identified, how can it be treated? If an ulcer is severe and deep, it may need a referral to an ophthalmologist for surgery. However, some cases may be rectified with medical management, which can be handled by a general practitioner. Overall, Broadwater recommended that ulcers with less than 50% stromal depth can be managed medically and monitored closely and ulcers of greater than 50% depth should likely pursue a referral to an ophthalmology specialist.

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Treatment

According to Broadwater, infected corneal ulcers are one of the most common causes of pain and vision loss in dogs and cats. However, with prompt and appropriate treatment, these poor outcomes can be avoided.

Broadwater stated, “The general 3 things to be aware of when you are thinking about treating these is treat, control, and prevent. Treat the infection. Control the pain; these are super painful, and I think it's overlooked of how painful ulcers are. Prevent self-trauma; e-collars for these [patients] are essential. Old school, hard plastic e-collars are the only ones that are going to work for this. Otherwise, they are going to ruin these eyes and they are going to make them worse in a short period of time.”

Treating the infection

Overall, these cases need to be treated aggressively. Broadwater recommended using frequent topical antibiotics, every 1 to 2 hours. Prescribing drops over ointments is preferred because of its efficacy in treatment and penetration abilities. “Oral antibiotics would be great and injectable antibiotics would be great [in theory], except there's no blood supply in the cornea. And it's probably not going to be there for a little while,” Broadwater said. “Sometimes you have to wait for the blood vessels to get there, but you got to fight that battle until then.”

“I usually start with broad spectrum antibiotics until my culture is available and we see if we have to change it. So, I use fluoroquinolones and I tend to stay away from tobramycin or gentamicin, again, until my culture becomes available,” he added.

Treating the enzymatic degradation

Once you have the proper antibiotics to treat the infection in the cornea, the next focus of treatment is stopping the “melting” process of the matrix metalloproteinases (MMPs) 2 and 9, which is an enzymatic degradation of the cornea. This is caused by the infection but needs additional medical management to combat.

To fight the enzymatic degradation and melting of MMP-2 and MMP-9, Broadwater advised to use topical serums or oral doxycycline. “We talked about oral antibiotics being of limited use and while that's true, doxycycline is probably the one exception. We're not really using it to treat the infection, per se. We're using it to stop that enzymatic degradation,” Broadwater said.

Treating the pain

Once the infection and enzymatic degradation is being treated, the final thing to focus on is treating the pain, because these cases can cause high levels of pain for patients. Topical or oral pain medication will work effectively, and a combination of both can also be an option. The brand can be dependent on your own preferences, according to Broadwater.

Avoid topical steroids and topical nonsteroidal anti-inflammatory drugs (NSAIDs) in these cases, however oral NSAIDs are safe. Broadwater stated that topical steroids and topical NSAIDs, “can increase the risk of infection at that time.”

Overall, when faced with an infected corneal ulcer that appears excessively deep or complex, seeking referral to an ophthalmologist stands as an invaluable resource. By doing so, patients can receive specialized care, including potential surgical interventions if necessary. Nonetheless, equipped with adept medical management skills, general practitioners play a crucial role in the initial assessment and treatment of such conditions.

For more coverage from Fetch Charlotte, visit our dedicated conference news page at dvm360.com/conference/fetch-charlotte.

Reference

Broadwater J. Infected corneal ulcers: medical and surgical management. Presented at: Fetch dvm360 Conference; March 15-17, 2024; Charlotte, NC.