Some challenges remain in the management of DME

There can be no doubt that anti-VEGF agents have revolutionized the management of diabetic macular edema. Whether we use monoclonal antibodies as in bevacizumab, antibody fragments as in ranibizumab or fusion proteins as in aflibercept to block VEGF, the randomized controlled multicenter international clinical trials have shown superior treatment outcomes in DME compared with laser or steroids. At 1 year the visual acuity gain is around eight letters, and this is maintained into the second year. Good glycemic control, blood pressure and lipid control are also important in the prevention of DME but appear to have little or no effect on treatment response to anti-VEGF. Nevertheless, there are still areas that need further attention and improvement in order to ensure the results that we see in clinical trials can be translated into the real world.Early intervention before center-involving DME has developed ensures the best clinical outcomes with anti-VEGF treatment. In countries where there is already a well-established diabetic retinopathy screening system, the audits show how effective such programs are at ensuring timely treatment and preserving sight. Even so, one of the major limitations with screening for DME is the high level of false positives that come through to the hospital eye service. Any screening program is rightly set up to ensure there are as few false negatives as possible (because a screening service should not miss any patients with the disease). However, with the current definition of M1 maculopathy (exudate within 1 disc diameter of the fovea, group of exudates at the macula, microaneurysms and a visual acuity worse than 6/12), many patients with a dry macula are taking up unnecessary space in medical retina clinics. The reported rates of false positive referrals are around 57.1% in a Hong Kong study, around 85% in a Singapore study and 59.7% in a U.K. study. The clinical trials using stereo imaging of the macula or OCT at the screening centers are currently ongoing, and results are anticipated shortly. In the meantime, many centers are setting up virtual clinics to reduce the number of patients with referable M1 maculopathy ending up in the medical retina clinics. In a virtual clinic, the patient has best corrected vision measured and a macular thickness OCT scan taken of both eyes. The patient is referred back to the diabetic retinopathy screening service (without ever being seen in the hospital clinics) if the retina is dry on OCT.