A patient interface device includes: a first interface port configured to be interfaced with a laser surgery apparatus; a second interface port configured to be interfaced with a patient's eye, the second interface port including an applanating lens for application to a patient's eye during a laser surgery procedure; a chamber extending between the first interface port and the second interface port and defining a chamber therein, wherein air may be evacuated from the chamber by the laser surgery apparatus via the first interface port. The second interface port also includes a retaining ring on which the applanating lens is provided, the retaining ring having through channels extending through the retaining ring from the chamber above the applanating lens to a space below the applanating lens.