10 week old pupils different sizes. saw pediatrician & ophthalmologist, both said its okay. should i take him to neurologist as well?

Some basics: There can be a subtle difference in the size of pupils in as many as 20% of normal infants. The difference is usually less than a millimeter. It tends to be more prominent is low light situations & can run in families. As long as the problem causes of this process have been excluded by the ophthalmologist I would see little that a neurologist would add. Consult as many as you wish.