A study on the normal values of inner canthal, outer canthal, canthal index, interpupillary distance and head circumference of 23 - 42 years Igbos

Abstract

Inner intercanthal distance is the measurement of the distance between the two medial canthi of the eyes, while outer intercanthal distance is the measurement of the distance between the lateral canthi of the eyes. Interpupillary distance is the distance between the pupils, measured from the center of one eye to the centre of the other eye when the eyes are focused on infinity. A study on the normal values of outer intercanthal, inner intercanthal distance, canthal index, head circumference, near and far interpupillary distance was conducted in 23-42 years old Igbos. A total number of 1000 subjects comprising 500 males and 500 females were recruited for this study. Measurements were obtained by using a vernier caliper on the medial and lateral angles of the eyes, while a non stretchable tape was used to measure the head circumference. Canthal index was derived by dividing the inner intercanthal distance by the outer intercanthal distance and multiplying by 100. Near and far interpupillary distances were derived by the use of a meter rule. Results showed that there was change of means with advancing age for the measured dimensions. The mean for the outer intercanthal distance was
102.06±4.43mm and 102.09±4.54mm for males and females respectively. Canthal index was 36.72±3.65 and 36.75±4.90 for males and females respectively. The head circumference, near and far interpupillary distance were 59.25±6.45 cm and 59.44±4.98 cm, 68.28±5.08mm and 68.45±5.12mm, 74.9±4.11mm and 74.5± 4.03mm respectively for males and females. There was no significant difference (p<0.05) between the males and females in the measured parameters and the canthal index.
This study has provided a database for this Igbo population and may assist craniofacial surgeons during surgery.