AIM:To observe the early dynamic changes of biometric parameters in guinea pigs model. METHODS: Twenty guinea pigs (age of 3 weeks) were randomly assigned to two groups: monocularly deprived facemask (MDF) group (n=10) and normal control group (n=10). All animals underwent biometric measurement (refraction, axial length and OCT) prior to the experiment. All animals in the MDF group underwent biometric measurement at each of the 5 time points (2, 4, 6, 10 and 14 days of form deprivation). RESULTS: In MDF group, choroidal thickness in experimental eye had become thinner than contralateral eye at 10, 14 days, but there were no significant differences between experimental eye and normal control eye.CONCLUSION: In early deprivation of guinea pigs’eyes, there is no significantly pathological and retinal thickness change. However, there is a trend towards shorter choroidal thickness.