Persistent diabetic macular oedema

Ongoing treatment with anti-VEGF agents in eyes with persistent macular thickening often produces long-term visual improvement, with very few patients worsening over time, according to a study conducted by Susan Bressler MD and colleagues. Speaking at the 34th Annual Meeting of the American Society of Retina Specialists in San Francisco, Dr Bressler reviewed a post hoc study that analyzed patients with persistent macular oedema treated in the Diabetic Retinopathy Clinical Research Network’s Protocol T study. “There are numerous randomized controlled clinical trials showing the visual benefits of anti-VEGF agents for DME. But we also recognize that there are many eyes, as many as 49%, that have persistent macular thickening of the centre subfield on OCT, one and two years after beginning anti-VEGF therapy. Current network protocols permit leaving DME in the centre along if it is stable,” noted Dr Bressler, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, US. The original Protocol T trial compared sham and prompt focal/grid laser, intravitreous ranibizumab and prompt laser, intravitreous ranibizumab and deferred laser, and intravitreous triamcinolone and prompt laser. The current analysis looked only at the subgroup of 117 ranibizumab recipients who had persistent macular oedema after six months of therapy. Patients received monthly injections for the first four months with additional fifth and sixth injections if the central macula remained thickened. At six months, the eyes with persistent thickening still had very similar vision to the patient group without persistent thickening, a difference of one letter. Both groups improved by seven to eight letters. Median change in visual acuity among the subgroup remained positive over the three year period. The eyes with persistent oedema that had cleared within the first six months had median visual acuity of 20/25 at three years, while those whose oedema persisted for three years were almost as good, with a median acuity of 20/32. Moreover, these patients typically received only half as many injections as would have been administered in the RISE and RIDE study protocols. “When applying these network protocols, fewer than half of eyes will have persistent oedema at six months. Of those, 60% will dry out within a three year period. Eyes that do resolve chronic persistent diabetic macular oedema do appear to have better visual outcomes, But either way, there is a respectable change in visual function, with only small percentage suffering vision loss. Given these relatively positive outcomes, the current strategy of leaving some degree of oedema when it is stable seems reasonable while we consider other treatment alternatives,” Dr Bressler concluded. Susan Bressler: sbressler@jhmi.edu

Tags: macular oedema, retina