Intravitreal antibiotic + steroid makes dropless cataract surgery possible

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A retrospective analysis including data from a consecutive series of 1575 eyes shows that intravitreal placement of triamcinolone/moxifloxacin during cataract surgery is a safe and effective method for preventing inflammation, endophthalmitis, and cystoid macular edema.

By Cheryl Guttman Krader; Reviewed by Stewart Galloway, MD

Memphis-Intravitreal placement of triamcinolone/moxifloxacin (“Trimoxi”) is safe, effective, and has advantages compared with topical medications for preventing inflammation, endophthalmitis, and cystoid macular edema (CME) after cataract surgery, according to Stewart Galloway, MD.

Dr. Galloway- clinical assistant professor of ophthalmology, University of Tennessee, Memphis, and private practice, Fairfield Glade, TN-reported his experience using Trimoxi in 1,575 consecutive eyes that underwent uncomplicated surgery with placement of a single-piece acrylic IOL.

Prepared by a compounding pharmacy, the preservative-free product contains 15 mg triamcinolone +1 mg moxifloxacin per mL. A dose of 0.2 mL is placed into the anterior vitreous after IOL implantation and prior to viscoelastic removal using a 27-gauge cannula passed through the zonules via the ciliary sulcus inferiorly.

“Intraoperative medication that avoids postoperative treatment eliminates out-of-pocket costs as well as compliance issues, and so has tremendous benefit, especially for elderly patients and considering how the cost of generic medications has skyrocketed,” Dr. Galloway said. “Its cost and compliance advantages also make the intraoperative regimen attractive for use in third world medicine.

“I believe instillation of the antibiotic and corticosteroid directly into the vitreous is ideal because it places the medications at the desired site of action and results in more prolonged exposure because the medications have a longer half-life in the vitreous than in the anterior chamber,” he continued.

Understanding the study

None of the patients in Dr. Galloway’s series initially used a topical corticosteroid or antibiotic. However, 22% of eyes were prescribed supplemental treatment with a topical nonsteroidal anti-inflammatory drug (NSAID) because they were receiving a premium IOL or considered at increased risk for CME due to diagnoses of diabetes mellitus (DM) or epiretinal membrane (ERM).

Patients were evaluated on the day of surgery at 4 to 7 hours postop and then at 3 weeks. All but 14 eyes had a minimum postoperative follow-up of 3 months. No eyes developed endophthalmitis, and rates of anterior chamber inflammation and CME (defined as any reduced best corrected visual acuity (BCVA) and optical coherence tomography-measured central macular thickness >220 µm, with or without cysts) at the 3-week postop visit were low, 2.5% and 2%, respectively.

Mean intraocular pressure measured at the first postop visit was slightly elevated (21.8 mm Hg). However, no eyes developed a steroid IOP response or needed IOP-lowering medication, and at the 3-week follow-up, mean IOP had decreased to 14.5 mm Hg.

Visual acuity (VA) results were good, but patients experienced a delay in recovery since the triamcinolone acetonide is a milky fluid. At the day of surgery evaluations, about half of the patients had BCVA of 20/100 or worse. However, by 3 weeks, BCVA was 20/40 or better in 96% of eyes and 20/25 or better in 79% reported Dr. Galloway.

“Use of Trimoxi requires more intensive patient education,” he said. “Patients need to understand their VA will be reduced in the immediate postop period. In addition, they are told to expect floaters in their superior field of vision for 3 to 7 days, and that they may notice a foreign body sensation at the incision site if they are not using a topical NSAID.

“However, even after given this information, almost all of my patients choose Trimoxi over a traditional topical medication regimen,” he continued.

Results

Results from subgroup analyses showed rates of anterior chamber inflammation were 1.7% in eyes of patients with diabetes, 4.3% in those with an ERM, and 6.3% in eyes that developed CME.

Dr. Galloway suggested that if patients had been seen for follow-up earlier than 3 weeks, the inflammation rate in his series might have been higher. However, if more stringent criteria were used to diagnose CME (presence of cystic changes on OCT and/or CMT >280 microns), the rate of CME would be lower, only 1.6%.

Subgroup analyses on CME rates based on the original criteria showed it was more common in eyes with DM or ERM than those without, 3.5% vs. 1.5%. Not all high risk eyes were prescribed supplemental treatment with a topical NSAID, but the incidence of CME was only 1.9% in those eyes that were.  

“The addition of a topical NSAID made a large difference in preventing CME in eyes with ERM, as the incidence of CME was 8.9% in untreated eyes but only 2.9% in eyes with an ERM receiving an NSAID. However, topical NSAID treatment did not significantly reduce the rate of CME in eyes of patients with diabetes,” noted Dr. Galloway.

“Therefore, I now only prescribe a topical NSAID in diabetics with pre-existing maculopathy. With this approach, I have greatly increased the proportion of patients that truly have ‘dropless’ cataract surgery,” he concluded.

Stewart Galloway, MD

E: eyeguy@frontiernet.net

Dr. Galloway has no financial interest to disclose.