A comparison of interpupillary distances between Turkish and Azerbaijani populations

Craniofacial anthropometric measurements demonstrate variability across populations.

This study aimed to compare far interpupillary distance (IPD) values between Turkish and Azerbaijani adult populations with presumed shared ethnic origins and to evaluate the potential influence of environmental factors.

A total of 1,400 healthy individuals aged ≥18 years were retrospectively analysed, comprising 700 subjects from Turkey and 700 from Azerbaijan. All participants underwent routine ophthalmological examinations, and only those without congenital or acquired craniofacial abnormalities were included. Participants were stratified by gender and six age groups (18-24, 25-34, 35-44, 45-54, 55-64, and ≥65 years). Far IPD was measured using digital autorefractometers.

The overall mean IPD was 62.1 ± 3.7 mm in the Turkish population and 65.0 ± 3.1 mm in the Azerbaijani population (p < 0.05). Males consistently had greater IPD values than females in both populations (p < 0.05). Significant differences in IPD were observed across age groups in both populations. For every age and sex category, the mean IPD in the Azerbaijani population was greater than that in the Turkish population.

Despite presumed shared ethnic background, significant differences in IPD were observed between the two populations. These findings suggest that environmental and geographical factors may contribute to craniofacial variation beyond ethnicity.