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Cataract surgeon describes early experience with transzonular delivery of medication
An investigator-initiated clinical trial of a compounded formula of medications injected during cataract surgery is underway.
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There are three primary goals with cataract surgery. The first is to perform the safest procedure possible, the second is to have great outcomes, and once those two are secured, the third is for the patient to have a good experience. With those goals in mind, I am testing injectable compounded formulations that have the potential to be used for most of my cataract surgery patients.
Safety first
Endophthalmitis or other infection is the No. 1 fear following cataract surgery, and not far behind that is inflammation, which can cause temporary or permanent retinal damage. Currently, the main modality to prevent these issues is topical pharmacotherapy given before, during and after surgery. A nonsteroidal anti-inflammatory drop is typically prescribed a day or two before surgery, and most patients use antibiotic and steroid drops for 6 weeks after surgery. While current medications do a good job of meeting the first goal of making the procedure safe, they do not contribute to a positive patient experience.
Drops are expensive for the patient, with many original formulations not covered by insurance, resulting in an increasing number of patients insisting on generic formulations even though they are inferior. In addition, patients are poorly compliant, as a number of studies have identified. When patients do self-administer drops, they are likely to either miss the eye entirely or hurt the eye by hitting it with the bottle. In short, the medication regimen is the primary complaint of most cataract surgery patients, and dealing with questions, complaints and refills for said medications creates a significant workload for staff.
Robert J. Weinstock
Injectable formulations
James Gills, MD, pioneered the technique of administering corticosteroids via intracameral injections during cataract surgery, but it was not always effective and did not resolve the need for antibiotics. However, there is now a compounded formula of U.S. Food and Drug Administration approved medications that can be injected into the vitreous (transzonular delivery) at the time of cataract surgery, which makes logical sense to me on many fronts. TriMoxi (triamcinolone acetonide and moxifloxacin hydrochloride, Imprimis Pharmaceuticals) and TriMoxi+Vancomycin (Imprimis Pharmaceuticals) use patent-pending technologies that allow for the combination of drugs into a single, cost-effective intraocular injection.
Injectable drugs make surgery potentially safer by delivering the medication directly into the eye to eliminate the risk of infection and inflammation, thereby canceling issues with noncompliance and user error. As scientists, physicians seek empirical evidence on which to base decisions. Therefore, I am now conducting an investigator-initiated clinical trial of TriMoxi to assess the efficacy of the injectable drug vs. standard drops.
Seeing results
The prospective study has 20 patients thus far. We are evaluating the ease of transzonular injection of the formulation during surgery, as well as the efficacy 1 week and 1 month postoperatively. Transzonular delivery has so far had no cases in which patients needed to be rescued with traditional drops. I warn patients beforehand that they may see some floaters after surgery, but most agree that a potential limited exposure to floaters is preferable to 6 weeks of expensive, inconvenient and irritating topical medications.
From my new user perspective, the injectable therapies appear to meet my requirements: They meet or exceed safety standards, and they improve the patient experience. This was sufficient information to motivate me to test the pharmaceuticals in a controlled fashion, which I am currently doing. While it is still necessary to study many more patients, the results thus far are encouraging for going dropless.