ObjectiveTo investigate the effect of short-wavelength monochromatic light on refractive development and eye growth in guinea pigs.MethodsTwenty male two-week old guinea pigs were randomly distributed into two groups (n=10 in each group):blue-light group (BL) and white-light group (WL). The BL group was raised under 430 nm monochromatic light, and the WL group was reared under white light with 5000 K color temperature. The light quantum number of the two groups was identical, 3×10-4 μmol·cm-2·s-1. The irradiance value was 0.527 mWcm-2 of blue light and 0.247 mWcm-2 of white light approximately. Biometric and refractive measurements were performed before and after treatment. ResultsBefore treatment, the differences between the biometric parameters of the two groups including refraction, corneal curvature and axial components were not significant (P>0.05). After 12-week exposure, the refraction increased 1.20±0.66 D in the BL group, and decreased 1.18±0.85 D in the WL group. There was a 2.40 D hyperopia in the BL group when compared with that of the WL group(P<0.0001). Meanwhile, the axial length and vitreous body grew 0.77±0.12 mm and 0.05±0.10 mm in the BL group, respectively, and they were extended by 0.95±0.18 mm and 0.21±0.13 mm, respectively, in the WL group. There was a slower speed of axial growth and vitreous body''s extension when compared with that of the control group (P<0.05). No significant differences were found between groups at the end of the research in the radius of corneal curvature, depth of anterior chamber and lens thickness (P>0.05). Conclusions 430 nm short wavelength monochromatic light can slow down the prolongation of axial length and vitreous body and induce hyperopia in guinea pigs.