No ground wire

I'm installing a Ring spotlight camera where an existing spotlight is currently. I took the old spotlight off and saw that there was no ground wire. However there is a ground screw in the old bracket. My house was built in 1950 if that matters at all. My question is, can I attach the ground wire from the Ring camera to just the ground screw, or does it need to be connected to a ground wire. Thank you for any advice.