A method for determining an optical performance parameter of a head mounted display device adapted for a wearer includes a head mounted display device providing step, during which a head mounted display device adapted for a wearer is provided,an optical measurement device providing step, during which an optical measurement device is provided that includes an entrance pupil and a sensor receiving light through the entrance pupil, a positioning step, during which the optical measurement device and the head mounted display device are positioned so that the position of the entrance pupil of the optical measurement device corresponds to the position of the pupil of the wearer when wearing the head mounted display device, an optical performance parameter determining step during which at least one optical performance parameter of the head mounted see-through display device is determined based on the data measured by the optical measurement device.