Diurnal variation in diabetic macular edema measured by optical coherence tomography

Purpose To investigate diurnal variation in diabetic macular edema using the Stratus OCT ( Carl Zeiss Meditec). Methods Forty eyes of twenty diabetic patients with diabetic macular edema underwent four optical coherence tomography (OCT) measurement of macular thickness with the fast macular thickness mapping protocol of the Stratus OCT at 9 AM, 12 AM, 3 PM, 6 PM. ETDRS visual acuity and refraction data were also collected at each time. Retinal thickness measurements from each of the nine areas of the retinal map, visual acuity and refraction were correlated over time. Results In our study we find a decrease delk macular thickness by means of OCT of 4%, 5%, 6% at 12 a.m. am 15 am 16 pm. In the group of patients with macular thickness bigger than 300 microns, we find change in the refraction of 2 patients. In the rest of patients (absence of macular edema,. slight macular edema), there were no significant changes of the macular thickness. Conclusion This study suggests that macular thicknening, as measured by the Stratus OCT, may spontaneously decrease in some patients with more severe macular diabetic edema over the course of the day.