2.4.2. Eyebrow Height
Standardised digital 2D photographs of the primary gaze were taken just before the surgery and 6 and 12 months postoperatively, with the head in a natural position, to assess eyebrow height. Each photograph was taken by the same researcher (M.H.J.H.) under the same lighting conditions, at a fixed distance and with the same camera (Nikon D5600 AF-S DX NIKKOR VR, Minato, Tokyo, Japan). To account for size discrepancy between photographs, a horizontal visible iris diameter of 11.71 mm was used for calibration purposes [a and a’: vertical line to the lower boundary of the eyebrow at the pupil’s midline;b and b’: vertical line to the lower boundary of the eyebrow at the lateral border of the iris;c and c’: vertical line to the lower boundary of the eyebrow at the exocanthion.The eyebrow height measurements were performed by one researcher (M.H.J.H.) and then repeated by an independent researcher (M.C.) to assess inter-observer variability.