Normal values of inner canthal distance, interpupillary distance and palpebral fissure length in normal Chinese children in Taiwan

Ocular measurements, including inner canthal distance, outer canthal distance, interpupillary distance, and palpebral fissure length are important in the evaluation of congenital deformities and posttraumatic telecanthus. In this research, 4446 normal Chinese children in Taiwan were enrolled in our study. The sample of 284 full term neonates, 2742 infants and children aged from 1 month to 3 years, and 1420 preschool children were measured for inner canthal distance, outer canthal distance, interpupillary distance and palpebral fissure length. We calculated the mean value and standard deviation of the ocular measurements in normal Chinese newborns, infants and preschool children in Taiwan under 5 years. No significant sex differences were observed. Compared with previous studies, inner canthal distance, outer canthal distance and interpupillary distance in Chinese children in Taiwan were wider than those in Caucasian children, but the palpebral fissure length was not significantly different. We also found that inner canthal distance was wider than palpebral fissure length at the same age; therefore it was not correct to diagnose hypertelorism in Chinese children in Taiwan; as if an imaginary third eye could fit between the eyes. Thus, we suggest that measurements should be adjusted with normal standards specific for race. Consideration of the position of eyes is relevant for the diagnosis of a large number of syndromes.