AIM: To compare serum Lutein and Zeaxanthin (L/Z) concentrations between patients with nonproliferative diabetic retinopathy (NDR) and normal subjects,and to explore the effect of L/Z supplementation on serum L/Z level and visual function in NDR patients METHODS: Subjects were divided into three groups: 30 NDR patients supplied with Lutein 6mg/d and Zeaxanthin 0.5mg/d for three months (DR Group),30 NDR patients without L/Z supplementation (DR Control Group) and 30 normal subjects (Control Group).Serum L/Z concentrations were measured by liquid high-resolution chromatography (HPLC).Visual acuity was recorded at baseline,1 month,2 months and 3 months post initial supplementation.Serum L/Z concentration were measured at baseline,1 month and 2 months post initial supplementation.Contrast sensitivity (CS) and fovea thickness were recorded at baseline and 3 months post initial supplementation.RESULTS: Mean serum lutein concentrations in DR group were 0.0686±0.0296μg/mL and zeaxanthin concentration was 0.0137±0.0059μg/mL.The L/Z level of DR group was significantly lower compared to the control group( lutein: 0.2302±0.1308μg/mL,zeaxanthin: 0.0456±0.0266μg/m,P = 0.000).The concentration of lutein and zeaxanthin in the DR control group at base line was 0.0714±0.0357μg/mL and 0.0119±0.0072μg/mL,respectively.There was no significant change of L/Z concentration in the DR control group during the study.Serum L/Z concentrations of DR group increased significantly after supplementation(F=109.124,P=0.000;F=219.207,P=0.000).Visual acuity improved significantly after medication.Compared with pre-medication,the average CS values of 1.5cpd,3cpd and 6cpd after three months increased significantly (P =0.030,0.013,0.008) and the foveal thickness decreased.(P =0.05) CONCLUSION: Serum L/Z concentrations in DR patients are significantly lower than those in normal subjects,and L/Z intake can improve the visual acuity,CS and macular edema in DR patients,suggesting that L/Z supplementation might be targeted as potential potential therapeutic agents in treating NDR. AIM: To compare serum Lutein and Zeaxanthin (L / Z) concentrations between patients with nonproliferative diabetic retinopathy (NDR) and normal subjects, and to explore the effect of L / Z supplementation on serum L / Z level and visual function in NDR patients METHODS Subjects were divided into three groups: 30 NDR patients supplied with Lutein 6 mg / d and Zeaxanthin 0.5 mg / d for three months (DR Group), 30 NDR patients without L / Z supplementation (DR Control Group) and 30 normal subjects Serum L / Z concentrations were measured by liquid high-resolution chromatography (HPLC) .Visual acuity was recorded at baseline, 1 month, 2 months and 3 months post initial supplementation. month and 2 months post initial supplementation. Contrast sensitivity (CS) and fovea thickness were recorded at baseline and 3 months post initial supplementation .RESULTS: Mean serum lutein concentrations in DR group were 0.0686 ± 0.0296 μg / mL and zeaxanthin conce ntration was 0.0137 ± 0.0059 μg / mL. The L / Z level of DR group was significantly lower compared to the control group (lutein: 0.2302 ± 0.1308 μg / mL, zeaxanthin: 0.0456 ± 0.0266 μg / m, P = 0.000). concentration of lutein and zeaxanthin in the DR control group at base line was 0.0714 ± 0.0357 μg / mL and 0.0119 ± 0.0072 μg / mL, respectively. There was no significant change of L / Z concentration in the DR control group during the study. L / Z concentrations of DR group increased significantly after supplementation (F = 109.124, P = 0.000; F = 219.207, P = 0.000) .Visual acuity improved significantly after treatment. (P = 0.05) CONCLUSION: Serum L / Z concentrations in DR patients are significantly lower than those in normal subjects, and L / 3 cpd and 6 cpd after three months increased significantly (P = 0.030,0.013,0.008) and the foveal thickness decreased Z intake can improve the visual acuity, CS and macular edema in DR patients, suggesting that L / Z supplemen tation mightbe targeted as potential potential therapeutic agents in treating NDR.