From what I understand, one of the pupils in your child's eye is smaller, this condition is known as Anisocoria, and it's causing him to have vision issues, so for this we will recommend that you visit a specialist.
While the pupils will remain just the way they are, but the vision-related issues can be fixed, refer our page - Pediatric Ophthalmologists in Mumbai.

Let us know your city for better recommendations, and drop us a message anytime you have any doubt!