Skyblinder staff, homebrew

If a flying creature you can see within 30 feet of you makes an attack roll against you, you can use your reaction to hold the staff aloft and cause it to flare with light. The attacker has disadvantage on the attack roll, and it must succeed on a DC 15 Constitution saving throw or be blinded until the start of its next turn.
You can use your reaction to cast "Light" cantrip. You know "Light" cantrip.