Patient's question:
When do newborns' vision and hearing start to develop?I used to read somewhere that they have vision after 2 days—is that true? Thank you!
Doctor's answer:
After birth, a child is equipped with vision, but the newborn's vision is very poor. Newborn infants have light sensitivity, as evidenced by their closing their eyes in response to bright light. They also react to changes in lighting, with their pupils constricting when bright light falls on their eyes, which is known as the light reflex. During the neonatal period, they can only see objects within 60 centimeters in front of them, with the optimal distance being 20 centimeters. For example, if you move a red yarn ball about 20 centimeters in front of the child, you can observe that their gaze can follow the moving red yarn ball for a short distance. Newborns have small eyes with a short anterior-posterior diameter, which results in physiological hyperopia. As the eyes develop, they gradually shift toward emmetropia, and vision improves over time.Normal newborns are born with excellent hearing orientation abilities. This is particularly remarkable when the baby hears familiar sounds, as it is a continuation of their intrauterine auditory experience. In the past, it was commonly believed that babies in the womb could not hear and were essentially "deaf," often in a "sleeping" state. However, in reality, babies in the womb maintain contact with the external environment from time to time through their auditory organs and behaviors, and they can even hear extremely low or high-frequency sounds that adults cannot detect.