You must be very careful to buy sunglasses for baby. You must buy the sunglasses under doctors advices. Usually most of glasses shop stored sunglasses for baby or kids. You can go your local glasses shop and ask their sellers. Or you can tries to browse it out from some reliable online optical shop. You may have a look at https://www.banzworld.com/ where sell many baby's products including sunglasses. Hope this helps.
Many optical stores offer sunglasses for babies. You can just go to the optical store to select sunglasses that are suitable for your baby. Or you can order sunglasses for your baby online. There are many online optical stores offering baby sunglasses like gap.com. Just search them online and you will get more information about baby sunglasses. When you get sunglasses for your baby, make sure the sunglasses can provide 100% UV protection. UV rays are extremely harmful to babies' eyes. If their eyes are exposed to UV rays for a long time, their eyes will be damaged by the UV rays and probably develop eye diseases in their later life.
There are many places you can get sunglasses for your baby. I have some suggestions for you. In the first place, you can go to some glasses stores. They have sunglasses in different styles and colors that are specially made for children. You can consult the technicians there. Secondly, you can also go to some online stores. There are more choices there for you and buying things online are more convenient and quicker. You can have a try .