C.B.
I would make sure to have a vision test with an ophthalmologist. My daughter was able to fool the nurse at the pediatrician's office until she was about 5 and then we found out from school that she failed the test there and had 20/200 in her left eye! She was treated with patches and glasses and is now up to 20/40 in that eye. But we have never done any blood or urine testing unless there was an indication that something might be wrong (like a UTI). I would tell the doctor that you are concerned since your son is autistic and can perhaps not tell you everything that is bothering him if it makes sense to do more comprehensive testing.