Computed exophthalmometry is an accurate and reproducible method for the measuring of eyeballs' protrusion

Purpose The aim of this study was to assess reproducibility of the repeated measurements from proposed computed exophthalmometry and to make a comparison with the Hertel exophthalmometer. Methods Computed tomography scans of patients with pathological (group 1) and intact orbits (group 2) were included in this retrospective study. In both groups, a single investigator measured a difference of eyeballs' protrusion using the proposed method of computed exophthalmometry. Briefly, the distances from the corneal apices of the left and right eyeballs to the line placed through the styloid processes of the temporal bones were measured and compared to each other three times independently. Results In some patients with intact lateral orbital rims the results of computed exophthalmometry correlated with the measurements from the Hetrel exophthalmometer. The analysis of the triple measurements with computed exophthalmometry revealed no significant difference in the value of standard deviation of the results in patients with intact and pathological orbits. In comparison with the Hertel-type exophthalmometry, the proposed method demonstrated very low variability and high repeatability of the measurements. The difference of 0.10–0.87 mm in the eyeballs protrusion should be considered as normal. Computed exophthalmometry is an accurate and reproducible method, which can be used for the measurements of eyeballs' protrusion.