Serous macular detachment in diabetic cystoid macular oedema

PURPOSE: To define serous macular detachment in patients with diabetic cystoid macular oedema (CME). METHODS: This study involved 78 eyes of 58 patients with diabetic CME. The patients underwent complete ophthalmic examination, fluorescein angiography and optical coherence tomography (OCT). Eyes with epiretinal membrane or vitreo-macular traction were not included in the study. Optical coherence tomography-3 was used in all patients and fundi were scanned on the horizontal, vertical and four oblique planes through the centre of the fovea. RESULTS: In all cases the increased thickness of the retina was related primarily to the hyporeflective intraretinal cavities. With OCT, 24 of 78 eyes (31%) had serous macular detachment as shown by retinal elevation over a non-reflective cavity with minimal shadowing of the underlying tissues. Fluorescein angiography did not show serous macular detachment in any patient. CONCLUSIONS: Our data showed that the incidence of serous macular detachment in diabetic CME was much higher than previously reported. Optical coherence tomography-3 allows an in vivo cross-sectional observation of very subtle serous macular detachment that is difficult to diagnose at the slit-lamp or by fluorescein angiography in patients with diabetic CME.