Evaluation of oxidative stress and dietary total antioxidant capacity i̇n diabetic macular edema

The aim of this study was to determine the serum levels of oxidative stress and total antioxidant capacity in diabetic macular edema (DME) cases and to determine the effect of these parameters on DME development as well as the effect of dietary antioxidant content by assessing the dietary total antioxidant capacity. For this purpose, 30 eyes of 30 patients diagnosed with Type 2 diabetes mellitus and DME, at least one eye with a central foveal thickness (CFT)  300 μm were evaluated as Group 1 while 30 eyes of 30 patients diagnosed with DME previously and both eyes with CFT < 300 μm were evaluated as Group 2. In the control group evaluated as Group 3, 33 eyes of 33 individuals with Type 2 diabetes mellitus and with no history of DME and/or diabetic retinopathy were evaluated. Optical coherence tomography (OCT) was used to assess CFT. Total antioxidant capacity (TAC) and total oxidative capacity (TOC) in the serum of each individual were measured. Dietary total antioxidant capacity was calculated by applying food consumption frequency questionnaire. There was no statistically significant difference among three groups in terms of serum TAC levels (p = 0,679). Serum TOC levels were found to be higher in Group 1 compared to other groups, and this difference was statistically significant (p <0,001). The dietary total antioxidant capacity was found to be the lowest in Group 1 and the highest in Group 3, and this difference was statistically significant between Group 1 and Group 3 (p = 0,003). Serum TOC values were positively correlated with CFT (p <0,001). There was no significant correlation between CFT and serum TAC values and the dietary total antioxidant capacity (p = 0,634; 0,333, respectively). It was determined that increase in serum TAC value caused a decrease in CFT while increase in serum TOC caused an increase in CFT. In our study, it was determined that oxidative stress in serum was associated with the development of DME. Additionally, the dietary total antioxidant capacity was found to be lower in patients with DME. Diet rich in antioxidants may be a preventive factor in the development of DME.