Sleeping with the light on occasionally is generally not harmful to the child. Sleeping with the light on for a long period of time may affect the child’s sleep quality, and frequent poor sleep quality may easily affect the child’s physical development and so on. Turning on the light only occasionally while the child is sleeping will generally not affect the child. If you sleep with the light on for a long time and the light is relatively strong, it may affect the quality of your child’s sleep and make your child’s sleep quality decline. As the body will secrete growth hormone at night while sleeping, the decline in sleep quality may make the growth hormone secretion is too small, which can affect the child’s physical development, but also lead to the child’s body immunity to reduce as well as the physical quality of the decline. Therefore, parents try not to turn on the light for a long time when the child is sleeping to avoid adverse effects.