Intravitreal Concentration of Sub–Tenon’s Injected Triamcinolone Acetonide

Abstract

Abstract: : Purpose: Sub–tenon’s injection of steroid has been a mainstay of treatment of intraocular inflammation. Recently, intravitreal steroid injection has been proposed for treatment of inflammation and edema. Although sub–tenon’s injection has been used for many years the concentration of triamcinolone entering the vitreous cavity is unknown. Knowledge of the penetration of triamcinolone following sub–tenon’s injection would allow comparison to known concentrations of intravitreal injections. Methods: 20 patients undergoing vitreous surgery received a 40mg injection of triamcinolone acetonide in the posterior sub–tenon’s space. Undiluted vitreous obtained at the time of surgery was evaluated by HPLC for steroid concentration. Intravitreal concentration at differing time durations from injection to time of surgery was plotted. Initial drug concentration was calculated. Results: Drug concentration ranged from 0.02 to 4.9 µg/ml with time durations between injection and vitreous removal ranging from 1 to 29 days. Calculated average initial drug concentration was 0.24 µg/ml. Conclusions: A wide range of vitreous concentration of triamcinolone acetonide is found following sub–tenon’s injection.

Keywords: vitreous • drug toxicity/drug effects • vitreoretinal surgery