Intravitreal triamcinolone therapy for diabetic macular oedema

It is less than 4 years ago since publication of the first report on the use of crystalline cortisone in the form of triamcinolone acetonide to treat recalcitrant macular oedema in patients with diabetes.1 This report of a single eye was rapidly followed by a case series from the same author (Jonas),2 who has remained faithful to a dosage regimen of 20 mg in a number of publications documenting the efficacy and side effects of this novel form of therapy.3–8 In parallel with Jonas, Martidis and co-workers in the United States9 reported on the use of a 4 mg dosage in a similar clinical scenario. Since then there have been many reports, including early results from a randomised controlled trial (RCT), utilising this somewhat lower dosage.10–15 All studies have thus far indicated a significant improvement in macular function and/or structure following injection, at least in the short term.

Why have different dosage regimens been employed? Triamcinolone acetonide is conveniently and affordably available in concentrations of 40 mg/ml in a sterile preparation (Kenolog, or Volon A or Kenacort depending on country, Bristol-Myers-Squibb) used commonly in other specialties such as orthopaedics. As 0.1 ml is the maximum volume most eyes can tolerate when injected into the vitreous cavity without causing inevitable central …