An ophthalmic surgical system enabling pressure measurements proximal to the eye may include an illumination probe having a probe tip configured for insertion through an incision in an eye of a patient. The probe tip may include a distal end of an optical fiber, wherein the distal end of the optical fiber includes a first reflective surface and a second reflective surface. The first and second reflective surfaces being separated by a cavity, wherein the second reflective surface is provided by a partially transparent wall forming an exterior surface of the distal end of the optical fiber.