Described herein are systems and methods for mounting optical sensors in physiological monitoring devices worn by a user to sense, measure, and/or display physiological information. Optical sensors may be mounted in the rear face of the device, emit light proximate a targeted area of a users body, and detect light reflected from the targeted area. The optical sensor may be mounted in a housing or caseback such that at least a portion of the optical sensor protrudes a distance from at least a portion of the housing. The protrusion distance may be adjustable such that a user may achieve a customized fit of the wearable device. Adjustment of the protrusion distance may also result in a customized level of contact and/or pressure between the optical sensor and the targeted area which may, in turn, result in more reliable and accurate sensing of physiological information.
