Normal values of ocular protrusion in Saudi Arabian male children.

The extent of ocular protrusion from the orbit is an important sign in the diagnosis and management of ocular and orbital diseases. Ocular protrusion is dependent, among other factors, on ethnic origin, age, gender, high refractive error, axial length, inter outer orbital distance (IOOD), and interpupillary distance (IPD). The purpose of this study was to provide normal absolute and relative ocular protrusion values for Saudi Arabian male children of Arab origin and to furnish regression equations relating ocular protrusion to age, IOOD, and IPD. A cross-sectional study was designed and ocular protrusion and IOOD were measured using a Hertel prism exophthalmometer. The IPD was measured by using a corneal reflection pupillometer. The data were analyzed using t-test and analysis of variance tests. The average absolute ocular protrusion of the right and left eye was 15.4 mm +/- 1.6 and 15.2 mm +/- 1.6, respectively. The maximum difference in protrusion between the eyes was 2.0 mm. Saudi Arabian male children of Arab origin who have ocular protrusion values outside the 95% confidence intervals should be advised to undergo additional diagnostic tests. A relative ocular protrusion value greater than 2.0 mm may be indicative of unilateral proptosis among these subjects. On the average, Arab children have more ocular protrusion than Caucasians but less than Chinese children.