The reasons why four-month-old babies do not see eye-to-eye with their mothers include strabismus and autism. 1. Strabismus: Most babies have small eyeballs at four months of age and suffer from farsightedness, which affects close-up vision. Secondly, if the optic nerve development is abnormal, it is also easy to cause strabismus, which makes it impossible for babies to see eye to eye. 2. Autism: Autism is mostly caused by genetic factors and will show symptoms of not being able to see eye-to-eye. However, the diagnosis is usually not confirmed in four-month-old babies and close observation is recommended. Most babies who don’t see eye-to-eye with their mothers at four months old are normal, so parents don’t need to be overly nervous. If this condition persists, it should be taken seriously and prompt medical attention should be sought.