Optical coherence tomography analysis of patients with untreated diabetic macular edema

Purpose Diabetic macular edema (DME) is a major cause of vision loss. Diabetes patients with mild macular edema and good visual acuity are often observed carefully so that treatment can be instituted when central vision is threatened. Optimal frequency of monitoring of these patients is unknown. Our study aimed to gather more information to determine a safe interval for monitoring of patients with eyes that were not undergoing active treatment for DME and to correlate outcomes with clinical risk factors. Methods Study population: Ninety-seven eyes with optical coherence tomography (OCT) evidence of DME of 97 patients with diabetes. Study procedures: Retrospective review of medical records and macular OCT scans at a 6–12-month interval. Primary outcomes: Change in visual acuity and change in central subfield thickness (CSFT) between the initial and follow-up OCT scans. Results There was no significant change from median baseline visual acuity 6/9 (inter-quartile range 6/6–6/12) or from median baseline CSFT (290 μm, inter-quartile range 270–312 μm) over a median duration of 8 months (inter-quartile range 7–10 months). The numbers of eyes where CSFT had increased ≥ 25 μm, reduced ≥ 25 μm, or remained unchanged were 16 (16%), 6 (6%), and 74 (76%), respectively. Patients with hemoglobin A1c ≥ 8.5% were 5.7 times more likely to develop central subfield thickening (95% CI 1.1–30.1, P = 0.038). Conclusions Majority of eyes with DME on OCT had stable CSFT without treatment over a median duration of 8 months. Hemoglobin A1c may be useful for risk stratification.