Dr. Jai Parekh: My name is Jai Parekh, and I'm a practicing ophthalmologist in Northern Jersey, where we have a large anterior segment practice. I also teach at the New York Eye and Ear Infirmary, where I'm an active associate professor of ophthalmology in their cornea service.
Dr. Marguerite McDonald: Hi. I'm Marguerite McDonald. I'm an ophthalmologist, and I'm a cornea specialist. I'm a clinical professor of ophthalmology at NYU in New York and also at Tulane in New Orleans, and I practice with the Ophthalmic Consultants of Long Island.
Dr. Richard Awdeh: Hi. My name is Dr. Richard Awdeh. I'm an ophthalmologist at the Bascom Palmer Eye Institute in Miami, Florida.
Dr. Sunil Thadani: I'm Dr. Sunil Thadani. I'm a cornea specialist, practicing in Western Maryland.
Dr. Jai Parekh: My go to therapy is Zirgan gel in treating patients that have HV keratitis.
Dr. Marguerite McDonald: My current approach in treating HSV keratitis is to use Zirgan gel five times a day until the epithelial defect is closed, and then for the next week, three times a day.
Dr. Richard Awdeh: I think there's several factors that are important when you treat HSV keratitis, the primary one of which is really a careful history from the patient. Really try to elicit whether there are prior episodes and this is a recurrent episode and how and when this current episode started.
Additionally, a very careful slit lamp examination is very important, looking specifically at the corneal epithelium as well as looking at the corneal stroma for signs of old scarring. I do staining of the corneal epithelium to look for pathognomonic signs such as dendrites. And if there's any question at all, I'll use a Millipore filter to do a culture to a corneal epithelium and send it to the microbiology lab for examination.
Dr. Sunil Thadani: My current approach to treating HSV keratitis is to use Ganciclovir gel five times daily for the first week and taper that down to three times daily for the second week, depending on the clinical response. Occasionally, I'll have to use antiviral oral treatment if I'm worried about compliance.
Dr. Jai Parekh: My approach changed in treating patients that had HV keratitis from oral to topical therapy, because as a physician and as a clinician, I know well that we treat topical disease with topical therapy.
Dr. Marguerite McDonald: When Zirgan gel became available in the United States, I immediately stopped using Viroptic drops.
Dr. Richard Awdeh: The introduction of Zirgan to the market was very important because it allowed access to an antiviral that had convenient dosing and targeted specifically infected cells on the ocular surface.
Dr. Sunil Thadani: My approach did change when Zirgan became available in the United States. I now use that exclusively for the treatment of HSV keratitis.
Originally, I had used oral antiviral treatment to promote epithelial healing.
Dr. Jai Parekh: And given the established safety profile of Zirgan gel, it's now become a big part of our armamentarium in treating patients that have HV keratitis.
Dr. Marguerite McDonald: My approach changed when Zirgan gel became available in the United States because I wanted to use an agent that targeted only virally infected cells. I'd been watching the data out of Europe. It's been available there for over a decade. And I was very impressed with it.
Secondarily, I did not want to use a product that was preserved with a mercurially based preservative.
Dr. Richard Awdeh: So, my approach changed because I appreciated the selectivity of Ganciclovir as well as the enhanced safety profile of the drug.
Dr. Sunil Thadani: Well, my approach changed, because I think if we can use a more targeted approach towards treating HSV keratitis and without sacrificing compliance, that's the preferable treatment. Historically, we really didn’t have a selective targeted topical therapy for the treatment of HSV keratitis until Ganciclovir gel came out.
Dr. Jai Parekh: It's very important for me when choosing an antibiotic or antiviral to have that agent go after the cells that are infected. Why would I want to go after something that's healthy?
Dr. Marguerite McDonald: It's really important for us in the US to now have an agent that selectively targets virally infected cells. That's why Zirgan gel has such a low toxicity profile. It only targets the virally infected cells.
Dr. Richard Awdeh: Selective action is important because it has--it allows for targeted therapy but then minimizes ocular surface toxicity.
Dr. Sunil Thadani: Well, the selective activation by the virally infected cells involves thymidine kinase, which activates the medication. And this really results in a more targeted approach. You know, the non-infected cells not having--being able to activate the medication really results in likely less toxicity for the patients.
Dr. Jai Parekh: The new buzzword right now in eye care is delivery system, how we deliver medications in a homogenous fashion to our patients. Zirgan gel is distributed in a homogenous fashion on the ocular surface.
Dr. Marguerite McDonald: Having a gel formulation and treating ocular surface disease or ocular infections, because there's increased contact time between the agent and the target tissues.
Dr. Richard Awdeh: Gel formulation is important because it allows for increased exposure of the drug at the site of action on the ocular surface and corneal epithelium and is particularly important for this disease state.
Dr. Sunil Thadani: Well, I think the benefit of a gel formulation has to do with the nature of the HSV keratitis. HSV keratitis causes dendritiform lesions that result in epithelial defects, which are often very painful for patients.
The gel formulation allows homogenous coverage of the corneal surface.