Abstract: An apparatus is disclosed for uniformly biasing a transducer against a human eye comprising an outer housing, an inner housing insertable into the outer housing and a biasing means. The inner housing has attached thereto a transducer and is movable with respect to the outer housing between an extended position and a retracted position. Bushing means are provided between the respective housings to maintain such housings in a concentric relationship and also to reduce friction between the respective housings. The probe is adapted to be applied against an eye and maintain substantially constant pressure on the eye, hand motion being compensated for by the biasing means, illustratively a spring.