A method and system provide a surgical system including a cassette, a console and an interferometric pressure sensing system coupled with the console. The cassette is for exchanging material with a patient and includes a wall and a reflector. The wall undergoes a deflection in response to a nonambient internal cassette pressure. The console is coupled with the cassette. The interferometric pressure sensing system is coupled with the console. The interferometric pressure sensing system includes a light source and a detector. The light source provides a first portion of light that is reflected off of the reflector and a second portion of light that bypasses the reflector. The first portion and the second portion of light are recombined to form an interference pattern. The deflection corresponds to a shift in the interference pattern detectable by the detector.