Intravitreal triamcinolone acetonide concentration after subtenon injection

PURPOSE: To determine concentration of intravitreal triamcinolone after subtenon injection. DESIGN: Prospective series of vitrectomy candidates and laboratory investigation. METHODS: Twenty eyes of 20 patients received subtenon injections of triamcinolone acetonide, 40 mg, before vitrectomy surgery. Exclusion criteria included previous history of vitrectomy, triamcinolone injection, and retinal detachment. Posterior subtenon injections were performed using the standard technique. Undiluted vitreous specimens were obtained at the time of vitrectomy, which was performed from one to 29 days after subtenon injection. Intravitreal triamcinolone concentration was determined by high-performance liquid chromatography. RESULTS: No complications were associated with subtenon injections. Intravitreal triamcinolone concentrations varied considerably, from zero in five eyes to a high of 4.94 microg/ml. CONCLUSIONS: Intravitreal triamcinolone concentrations vary considerably after subtenon injection. The findings indicate that subtenon injection can be a method for administering intravitreal triamcinolone acetonide that is comparable, in some cases, to the levels achieved after intravitreal injection.