You can schedule this with a cron job or task scheduler using a desktop notification command like:
notify-send "Eye Break" "Look 20 feet away for 2 minutes" -t 5000 desktop-reminder 2
osascript -e 'display notification "Look 20 feet away for 2 minutes" with title "Eye Break"' This is small, actionable, and scientifically backed (prevents digital eye strain). You can schedule this with a cron job