Determination of the normal range of exophthalmometric values for black and white adults

We used the Hertel exophthalmometer to measure the degree of protrusion in 681 adults, ranging in age from 18 to 91 years. The 327 white and 354 black subjects had no history of orbital or endocrine disease, severe myopia (more than -7 diopters), or buphthalmos. The mean normal protrusion values were 16.5 mm in white men, 18.5 mm in black men, 15.4 mm in white women, and 17.8 mm in black women. Although protrusion values above 21 mm are usually considered abnormal, we found that the upper limits of normal were 21.7 mm for white men, 24.7 mm for black men, 20.1 mm for white women, and 23.0 mm for black women. These differences were statistically significant (P less than .025). No individual had more than 2 mm of asymmetry between eyes.