The Canadian Association of Optometrists published a position statement in 2017 on the use of digital device screens by children. Here are their recommendations by age:
Screen Time for Toddlers 0–2 Years
None, with the possible exception of live video-chatting with parental support, due to its potential for social development, though this needs further investigation.
Screen Time for Preschoolers 2–5 Years
No more than 1 hour per day. Programming should be age-appropriate, educational, high-quality, and co-viewed, and should be discussed with the child to provide context and help them apply what they are seeing to their 3-dimensional environment.
Screen Time for Kids & Teens 5–18 years
Ideally no more than 2 hours per day of recreational screen time. Parents and eyecare providers should be aware that children report total screen time use as much higher (more than 7 hours per day in some studies). This is not unrealistic considering the multitude of device screens children may be exposed to in a day, both at home and at school. Individual screen time plans for children between the ages of 5–18 years should be considered based on their development and needs.
Further Screen Time Recommendations:
Breaks no later than after 60 minutes of use (after 30 minutes is encouraged). Breaks should include whole-body physical activity. The ideal length of break has not been identified for either children or adults.
Workstation ergonomics: Chair heights should be set such that the child’s feet can lay flat on the floor or on a stool underneath the feet to allow for support. Chairs should not have arm rests unless they fit the child perfectly, as should back rests. Desks should be set at the child’s elbow height or slightly lower. There should be enough depth on the desk to allow for forearm support; this is specifically effective in preventing musculoskeletal strain.
Displays should be set in front of the child. There is no official recommendation for the angle of screen inclination. For computers, it is recommended to place the top of the display or monitor at the child’s eye level, and then allow them to move the screen down into a comfortable viewing position as needed. Official recommendations regarding a screen’s distance from a child do not exist; the computer screen should be placed at arm’s length, and then moved as necessary.
External devices such as keyboards should also be placed in front of the child, with the mouse close to the keyboard and appropriately sized. Workstation lighting should be equal throughout the visual field, so glare and reflections that inhibit screen viewing or cause visual discomfort are inhibited.
The use of screens should be avoided one hour before bedtime. Screens in the bedroom are
Outdoor activity over screen time should be encouraged
Children may or may not complain of electronic screen-associated discomfort. Regular eye
exams, which assess a child’s visual ability to cope with their visual demands and offer treatments for deficiencies (e.g., glasses correction; treatment (other than glasses) of other contributing eye conditions, etc.) are recommended.