Purpose: To investigate the rhodopsin expression in form-deprived and defocus myopia in guinea pig and study the relationship between the rhodopsin expression and experimental myopia.
Methods: Fourty guinea pigs were randomized into the form-deprived group and the defocus group (n = 20). Guinea pigs in the form-deprived group wore a diffused (rigid glass-permeable contact lens (RGP) on one eye since one week after birth. Those in defocus group wore a -4 D RGP on one eye. The contralateral eyes were left as control. Refraction, axial length and depth of vitreous cavity were measured after 1 and 2 weeks respectively. Retina were dissected at 10-12 o'clock in the morning. The level of rhodopsin and its mRNA were observed through Western-blot and real-time PCR respectively.
Result: There is no difference between form-deprived group, defocus group and control groups (except refraction in form-deprived group). One week later, there is no difference between the form-deprived group, the defocus group and the control groups (except refraction in form-deprived group). Two weeks later, eyes in the form-deprived group and the defocus group became myopic. Its axial length lengthened and depth of vitreous cavity appeared deep. The form-deprived groups showed an increased expression of rhodopsin and its mRNA compared to the control groups. There is no difference between the defocus group and the control groups.
Conclusion: Expression of rhodopsin might involve formation of form-deprived myopia, but has less influence on defocus myopia.