Which one is the safest: All the above 4 brands have national Class II medical device license, so there is not much difference in safety.
Which is the most effective: the basic principle of the four brands are the same, the theory is effective, but due to the individual differences in the child's reason, there will be some children's effect is not ideal. The reason for this has a lot to do with the child's development, genes, strength of eye habits, and whether the device is used correctly.
3. Difference: Here are only the more familiar popular products:
YiZiLiang: brand inventor is Prof. JiangShunFu one of the founders of laser medicine in China, Professor ZhuPing joint research and development. The advantage of this feeder is the alternating use of internal and external laser, the theory is: when the internal laser has controlled the eye axis after the use of external laser prevention and control can be, alternating with each other, Chinese and Western medicine interaction.
The new generation of Yixiangliang, on the basis of the original increase of 3 levels of laser intensity adjustment, is equivalent to cover all the market nursing instrument red light intensity.