[Effects of flashing light on ocular growth and development of myopia in pigmented guinea pigs]

To investigate the effects of flashing light exposure on ocular growth and development of myopia in guinea pigs.

Thirty 4-week-old pigmented guinea pigs were randomly divided into three groups. Animals in group I were reared with the flashing light continuously and lasted for 6 weeks. The flashing frequency was 15 times per minutes and every flash includes 2 seconds light on and 2 seconds dark. Animals in group II and III were reared with normal light on, and the illumination cycle was 12 hours light/12 hours dark in group II and 24 hours light in group III. After 6 weeks, the effects of flashing light on eye development were assessed by cycloplegic retinoscopy, a-scan ultrasonography and eye weight. The histopathology changes of sclera, choroids and retina in posterior pore of the eye were examined using light microscope and transmission electron microscope.

At the end of the treatment period, guinea pigs reared in flashing light exhibited -7.00 D myopia, eye axial elongated 0.56 microm, and the weight increased 68 mg. The histopathology examination showed that the posterior sclera fibroblast become more active, the cell number increased, and the place between fibers became larger, the posterior choroids became thinned, and the outer membrane of photoreceptor cells became shorter and irregular, when compared with the control groups.

Flashing light can promote ocular growth and induce myopia in pigmented guinea pigs.