AIM: To observe retinal ultrastructural features and retinal cell apoptosis of defocus induced myopia in guinea pigs.

METHODS: Thirty guinea pigs(3-wk old)were received -10.00D rigid contact lenses(RGP)on the right eye and without wearing glasses on the left eye. Diopter change with cycloplegic retinoscopy, ultrastructural features of the retina with transmission electron microscopy were observed, the apoptosis of retinal cell by TUNEL immunofluorescence staining after 3wk were detected.

RESULTS: Eye diopter difference was 3.28±0.21D in the right eye and 1.55±0.23D in the left eye before and after induction. There was significantly statistical difference(P<0.01); Retinal ultrastructural features were showed with transmission electron microscopy(TEM)the retinal disk membranes edema, some shedding, mitochondrial swelling and deformation, small amount of vacuolar changes in the inner and outer nuclear layer cells. Some characteristics of apoptosis were also be seen such as cell membrane irregular contractions, irregular nuclear chromatin aggregation. The incidence of retinal cell apoptosis was(2.42±1.24)% in the right eye and(0.29±0.08)% in the left eye after induction. There was significantly statistical difference(P<0.01).

CONCLUSION: Accompanied by abnormal apoptosis of retinal cells during the formation of defocus-induced myopia in guinea pigs.