A simple bash script that turns off your screen for `SECONDS_TO_CLOSE_EYE` after `MINUTES_TO_WORK` long work to force you relax your eyes.

eyeProtector.sh

#!/bin/bash
#
# Set this script to start on login using `StartUp Application`
#

########-- CHANGE THESE FOR DIFFERENT BEHAVIOUR --#############
MINUTES_TO_WORK=45
SECONDS_TO_CLOSE_EYE=60
###############################################################

SECONDS_TO_WORK=$(echo $MINUTES_TO_WORK*60 | bc)

REFRESH_TIMEOUT_SECONDS=2
MULTIPLE_OF_RTS=$(echo -e "$SECONDS_TO_CLOSE_EYE/$REFRESH_TIMEOUT_SECONDS" | bc)

for pid in $(pidof -x eyeProtector.sh); do
    if [ $pid != $$ ]; then
        echo "Process already running"
        exit 1
    fi
done

while [ 1 ]
do
    sleep $SECONDS_TO_WORK
    $(paplay /usr/share/sounds/ubuntu/stereo/message.ogg)
    notify-send "Bro, close your eyes for 2 minutes"
    sleep 5

    I=0;
    while [[ I -le $MULTIPLE_OF_RTS ]];
    do
        xset -display :0.0 dpms force off
        I=$(echo "$I+1" | bc)
        sleep $REFRESH_TIMEOUT_SECONDS
    done

    $(paplay /usr/share/sounds/ubuntu/stereo/message.ogg)
    notify-send "Back to work"
    xset -display :0.0 dpms force on
done