Too much use of screens is not good for children. Restrict the use. Redness in children is usually due to dust allergy.
Next Steps
Wash the eyes child more often with cold water. Refresh tears eye drop 4times/ day can be used.If there is itching you can also start olopat eye drop 2 times/ day.
Health Tips
Try this for a month .. if no relief better to take a online or offline consultation.