AIM:To observe the changes of retinal and choroid tissue structure in SD rats exposed to blue light from 455nm-470nm array, and to analyze the relationship between irradiation time and tissue structure changes.

METHODS: Totally 24 healthy SD male rats of 6wk were selected and randomly divided into normal control group(n=6)and experimental group(n=18). The normal control group was fed for 6wk without any intervention. The experimental group was divided into three groups, which were exposed to the array blue light emitting apparatus(455nm-470nm, 391Lx)for 3, 6 and 12h each day for 6wk.

RESULTS: The fundus tissue structure was intact and the cell morphology was normal in the control group. With the extension of blue light irradiation time, the choroid fiber connective tissue of rats in all experimental groups presented hyaline changes, local loose edema, proliferation of small blood vessels, thinning of pigment layer, thinning of cells, gradual reduction of the number of visual cells, and local disappearance. At 3h, the nucleus staining of the experimental group was clear, and no definite changes were observed in the bipolar cell layer and ganglion cell layer. In the 6h and 12h groups, nucleus pyknosis was observed, bipolar cell layer was mildly proliferated, and local cytoplasm was formed in the ganglion cell layer.

CONCLUSION: The photoreceptor cells of retina become thinner, atrophy and disappear with the extension of blue light irradiation time. There was no significant relationship between the injury of pigment epithelial cells and the prolonged exposure time of blue light.