AIM: To expose rat retinal Müller cells to 530 nm monochromatic light and investigate the influence of varying light illumination times on basic fibroblast growth factor(b FGF) and transforming growth factor-β1(TGF-β1) expression.·METHODS: Three groups of rat retinal Müller cells cultured in vitro under a 530 nm monochromatic light were divided into 6, 12 and 24 h experimental groups,while cells incubated under dark conditions served as the control group. The b FGF and TGF-β1 m RNA expression, protein levels and fluorescence intensity of the Müller cells were analyzed.·RESULTS: The b FGF m RNA expression and protein levels were significantly upregulated in Müller cells in all three experimental groups compared with the control group(P <0.05), while that of TGF-β1 was downregulated(P <0.05). Also, b FGF expression was positively correlated,but TGF-β1 expression was negatively correlated with illumination time. The largest changes for both cytokines were seen in the 24 h group. The changes in b FGF and TGF-β1 fluorescence intensity were highest in the 24 h group, and significant differences were observed among the experimental groups(P <0.05).·CONCLUSION: The expressions of b FGF and TGF-β1changed in a time-dependent manner in Müller cells exposed to 530 nm monochromatic light with 250 lx illumination intensity. Müller cells might play a role in the development of myopia by increasing b FGF expression or decreasing TGF-β1 expression. Changes in cytokine expression in retinal Müller cells may affect monochromatic light-induced myopia. AIM: To expose rat retinal Müller cells to 530 nm monochromatic light and investigate the influence of varying light illumination times on basic fibroblast growth factor (b FGF) and transforming growth factor-β1 (TGF-β1) expression. METHODS: Three groups of rat retinal Müller cells cultured in vitro at 530 nm monochromatic light were divided into 6, 12 and 24 h experimental groups, while the cells incubated under dark conditions served as the control group. The b FGF and TGF-β1 m RNA expression, protein levels RESULTS: The b FGF m RNA expression and protein levels were significantly upregulated in Müller cells in all three experimental groups compared with the control group (P <0.05), while that of TGF-β1 was downregulated (P <0.05). Also, b FGF expression was positively correlated but the TGF-β1 expression was negatively correlated with illumination time. The largest changes for both cytokines were seen in the 24 h group . The changes in b FGF and TGF-β1 fluorescence intensity were highest in the 24 h group, and significant differences were observed among the experimental groups (P <0.05). · CONCLUSION: The expressions of b FGF and TGF-β1 changed in a time -dependent manner in Müller cells exposed to 530 nm monochromatic light with 250 lx illumination intensity. Müller cells might play a role in the development of myopia by increasing b FGF expression or decreasing TGF-β1 expression. Changes in cytokine expression in retinal Müller cells may affect monochromatic light-induced myopia.