20/40.is it bad on a 6year old

My son is 6 years old and has a 20/40 vision and was prescribed glasses very +4.00 is that bad?

[Houman Vosoghi, MD]

Assuming with the best correction in place the vision is 20/40, it may imply he is developing amblyopia or lazy eye.  He needs to be under the watchful eye of a pediatric ophthalmologist to make sure this is adequately treated and that the prescription was checked accurately (needs special drops to paralyse focusing muscles in a six year old and a more objective measure with a retinoscope).  Has to be a PEDIATRIC OPHTHALMOLOGIST and no one else!

HV