Intravitreal injection of triamcinolone acetonide and intraocular pressure

Editor, We read with interest the article by Kotliar et al. (2007). These authors investigated the extent to which intravitreal injections increase intraocular pressure (IOP). They calculated the effect for intravitreal injection of triamcinolone acetonide (IVTA) 4 mg in 0.1 ml solution in 22 patients. They concluded that paracentesis might be justified after intravitreal injections of 0.1 ml of a substance to avoid a short-term increase in IOP. We think this is an interesting paper, but we believe there is a need for further clarification on the best procedures for administering intravitreal injections. Although we agree with the authors that an increase in IOP can be induced by intravitreal injections, we do not think paracentesis should be recommended. Recently, we described the use of the Honan balloon to reduce IOP before IVTA; the Honan balloon was applied at 30 mmHg for 10 mins and the injection was then performed no more than 5 mins after the balloon’s removal. We reported the results of this technique in 19 patients with retinal vein occlusion (Hernaez-Ortega & Soto-Pedre 2007). All patients had received an intravitreal injection of 8 mg purified triamcinolone acetonide in 0.2 ml balanced salt solution under sterile conditions in topical anaesthesia (Hernaez-Ortega & Soto-Pedre 2006). Our procedure resulted in a significant reduction in IOP, and no complications such as central retinal artery occlusion or endophthalmitis were observed after the injection. Current proposed guidelines for intravitreal injections do not recommend excessive eyelid manipulation, but instead recommend that pressure should be applied directly to the globe (Aiello et al. 2004). The risk of massage is that any squeezing of the eyelids may cause the contents of the Meibomian gland to be expelled, thereby increasing the risk of infection. Obviously, this risk is even higher when IVTA is performed before or after an anterior chamber paracentesis to reduce intraocular volume. Therefore, digital massage and anterior chamber paracentesis before or after injection, although feasible, do not seem to be appropriate methods of reducing IOP. We encourage the authors to consider the use of the Honan balloon as a quick and safe procedure for reducing IOP that may be useful for intraocular injections of pharmacological agents.