[Prognostic factors for visual outcome after intravitreal drug therapy for chronic diabetic macular oedema]

In recent years, intravitreal bevacizumab and triamcinolone acetonide (TA) have been widely used to treat diabetic macular oedema (DMO). However, the indication criteria are not clear. The purpose of this study was to evaluate factors which are decisive for long-term visual outcome after intravitreal drug treatment for eyes with DMO.

Fifty eyes (37 patients) treated with intravitreal bevacizumab, TA, or sequentially with both for DMO with a minimum follow-up period of 6 months were analysed retrospectively. The eyes with an increase of best-corrected visual acuity (BCVA) at the last visit were classified as gainers, and eyes with stable or decreased BCVA as non-gainers. Clinical and imaging findings were evaluated.

BCVA significantly increased in 22 eyes and decreased in 28 eyes after a mean follow-up period of 14.6 ± 6 months after initial intravitreal intervention. Unfavourable for the long-term visual outcome was the presence of cystoid macular oedema (CMO, p < 0.001), whereas an early response at 5 weeks into therapy indicated a positive outcome (p = 0.016). The initial central macular thickness measured by OCT, the type of agent used in monotherapy, age and gender were without influence on long-term visual acuity.

An initial CMO is unfavourable for the prognosis of long-term visual outcome of DMO. Hence, benefit from intravitreal treatment with bevacizumab and/or TA is more likely in the early stages of chronic DMO before CMO has evolved. In eyes without CMO even a low number of injections is beneficial. An early response following intravitreal bevacizumab or TA is a predictor of long-term benefit.