The present invention relates to patient interfaces optically indicating a user that a member of the patient interface needs to be replaced due to wear. In particular, the present invention relates to a member for patient interface which includes at least one functional material having a predefined functionality and at least one indicator wherein the concentration of the at least one indicator in the member correlates with the predefined functionality of the at least one functional material.
Patient interface (
50
) optically indicating a user that a member (
22
) of the patient interface (
50
) needs to be replaced due to wear. In particular, it relates to a member (
22
) for patient interface (
50
) which comprises at least one functional material (
32, 34
) having a predefined functionality and at least one indicator (
28, 30
) wherein the concentration of said at least one indicator (
28, 30
) in said member (
22
) correlates with the predefined functionality of said at least one functional material (
32, 34
).