Impact of thiazolidinediones on macular thickness and volume in diabetic eyes

Objective: To assess the impact of thiazolidinedione (TZDs) use on macular thickness and volume in patients with diabetes with no macular edema and no diabetic retinopathy (DR) or mild nonproliferative diabetic retinopathy (NPDR). Design: Cross-sectional prospective pilot study. Participants: One hundred twenty patients (60 in each group) were enrolled, but 108 completed the study (59 in the TZD group and 49 in the non-TZD group). Methods: Patients with type II diabetes mellitus were categorized into 2 groups depending on TZD intake. Those with no prior history of treatment for DR were considered for the study. Patients in both groups had assessment of visual acuity and dilated fundus examination. Only patients with no evidence of macular edema and no DR or mild-NPDR were included. Spectral-domain ocular coherence tomography (SD-OCT) was used for measurement of central retinal thickness (CRT) and macular volume. Main outcome measure was difference in mean macular volume and central thickness between the TZD and the non-TZD groups. Results: Baseline demographics and characteristics were well matched between both groups. There was no significant difference in mean CRT of both groups (p = 0.13), but macular volume was significantly lower in the TZD group (p = 0.038). Conclusions: Patients with no macular edema and no DR or mild NPDR on TZDs did not show evidence of fluid retention in the macula on SD-OCT. Larger studies are needed to confirm these results.