Apparatus, systems and methods employing contact lenses having one or more sensor that sense an analyte in tear fluid and one or more recesses that collect the tear fluid. In some aspects, a contact lens includes a substrate that forms at least part of a body of the contact lens and a recess formed within the substrate configured to collect tear fluid when the contact lens is worn. The contact lens further includes at least one sensor disposed within the substrate configured to sense presence of an analyte in the collected tear fluid.
