Quantitative evaluation of hard exudates in diabetic macular edema by multicolor imaging and their associations with serum lipid levels

Aims To quantify hard exudates (HEs) by multicolor imaging (MCI) and traditional color fundus photography (CFP) in diabetic macular edema (DME), and study their associations with serum lipid levels. Methods Observational study. DME patients with HEs were recruited. The HE area and location both by MCI and CFP were measured by ImageJ software. Multivariate regression models were used to analyze the associations of serum lipid levels with the total HE area and HE location. Results Sixty-two patients (74 eyes) were enrolled to quantify HEs in DME. The total HE area by MCI was larger than that by CFP ( P = 0.004), and the distance between the fovea and the nearest HE by MCI was shorter than that by CFP ( P = 0.003). The percentage of patients with HEs involving the central macula by MCI was significantly higher than that by CFP ( P < 0.001). Furthermore, 62 eyes of 62 patients were included to analyze the associations of HE parameters with serum lipid levels. In both MCI and CFP, the HE areas were positively associated with triglyceride level ( P = 0.016, P = 0.022, respectively). HEs involving the central macula were positively associated with triglyceride and low-density cholesterol levels in MCI ( P = 0.028, P = 0.046, respectively), while no significant association was found between serum lipid levels and HE location in CFP. Conclusions MCI is superior to traditional CFP for the detection of HEs and the analysis of associations between HEs and serum lipid levels in DME.