Cerebral palsy is caused by damage to the infant brain. This damage can involve not only the motor parts of the brain, but also the parts that deal with vision. This is not related to damage to the eye but is related to damage of the parts of the brain that process visual information.
When first meeting a parent who's had a child newly diagnosed with cerebral palsy, I really want to try and help them understand their baby. It can be difficult for parents to take it in all at once and many leave that first interview quite overwhelmed, but you're going to meet some really important and helpful people.