An adherence device 100, including an attachable component to secure to an eye drop bottle cap and a monitoring component 110. The monitoring component 110 includes a sensor 170 to detect each eye drop administration. The attachable camponent may be a “universal cap” capable of securing onto any eye drop bottle cap while still permitted normal FDA-approved water-tight closure. The cap is capable of being removed and transferred to a different eye drop bottle for reuse.
