A new instrument for orbital anthropometry is described. It consists of the base for a slit-lamp upon which the patient's head rests and rulers mounted on three independently movable axes. The z-axis probe is used to measure sagittal relationship between the corneal apices and points on the orbital perimeter. The instrument was tested against a sliding caliper and its accuracy was found to be within 0.2 mm or 2%. Intra- and inter-observer reliability were assessed by repeated measurements of two subjects by three observers. The intra-observer reliability was 0.99. Variations between observers was not significantly different for points orbitale inferius (oi), nasion (n), and orbitale superius (os), however, there was a statistically significant difference for measurement of orbitale laterale (ol). The correlation between anthropometric readings for lateral orbital wall to apex corneal (ol-ac) and CT scans for the same landmarks was assessed. Analysis of variance showed no difference between the measurement methods. This anthropometer is convenient and accurate for measurement of the sagittal orbital-globe relationships. A disadvantage is that it cannot be used intraoperatively.