28.    Ethnic characteristics of the eyelashes: comparative analysis in Asian and Caucasian females. 
Oh Sang Kwon(1), Jung Im Na1,Beom Jun Kim1, Won Seok Park2, Jun Kyu Oh3, Kwang Hyun Cho1, Hee Chul Eun1, Kyu Han Kim1. 1.Department of Dermatology, Seoul National University Hospital, Seoul, 2.Skin Research Institute, AmorePacific R&D Center, Gyeonggi-do, 3.Rich Hair Clinic, Seoul, South Korea.

Despite of similar biochemical composition of human hair between races, physico-morphological characteristics are not identical in different ethnic groups. Eyelashes have been far less investigated than scalp hair, and the information available is insufficient. This study was performed to obtain basic information about eyelashes and to clarify differences between female eyelashes in Asians and Caucasians. Twenty Asian and 10 white Caucasian female volunteers aged between 20 to 29 years were admitted. Lateral digital photographs of upper eyelashes were taken and curl-up and lift-up angles of upper eyelashes were measured from lateral views. Images of upper eyelashes were also taken by using phototrichogram technique and total numbers, lengths, and thicknesses of upper eyelashes were obtained. Central portion of eyelashes or whole eyelashes were clipped and images were taken immediately and seven days later to obtain growth rate and anagen ratio of upper eyelashes. Numbers and thickness of eyelash cuticular layers were obtained by electronmicroscopy. Compared with Caucasians, Asian eyelashes revealed lower lift-up and curl-up angles, lower numbers, and a thicker transverse diameter. But, no statistical difference was observed in length or growth rate. Duration of anagen was estimated about 2 months. The eyelash anagen ratio obtained from 5 Asians was 17.8 ¡¾ 3.3%. By electronmicroscopy, the number of cuticular layers in transverse section was greater in Asian (8.0 ¡¾ 1.2) than Caucasian females (6.5 ¡¾ 1.1), but no statistical difference was found in single cuticle layer thickness between two groups. Moreover, eyelash characteristics were not influenced by eye-makeup in either race.
Our results on eyelash morphology and growth characteristics demonstrated significant ethnical differences in Asian and Caucasian females that could provide basic information for future investigations.