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.
Let me tell you about multimodal communication. We, as typical communicators, all use many different strategies. We use speech, gestures, facial expressions, technology, and no-tech solutions. As communicators, we all size up the situation based upon our communication partners, the context, the environment and then we choose to use the most effective communication strategy.