Hertel exophthalmometry: the most appropriate measuring technique

Editor,—The common method used in Hertel exophthalmometry involves aligning the corneal apex with the reference cone on the exophthalmometer and noting the position of this alignment on the millimetre scale (method 1). Keeler, the manufacturers of the exophthalmometer, recommend that the reference cone is aligned with the reference line on the millimetre scale and the position of the anterior …