Any way to count blinks with opencv? (ACCURATELY)

I have looked on many online project that use opencv mediapipe and dlib and all of them don’t really get very accurate about identifying a shut eye.

The facemesh always shows some distance between the eyelids even when the eyes are completely shut.
The vertical line is non-zero even though it should be zero what the eye is closed.

This unfotunately is not accurate enough for my needs (dry eye clinic therapy).

Is there a way to get a more accurate measure of the closed eye?

thank you