Analysis of the Patterns of Lateral Canthal Rhytids and Reference for Botulinum Toxin Treatment in Orientals

Background One of the earliest signs of aging is the appearance of wrinkles in the skin at the outer corners of the eyes (lateral canthal rhytids). The purpose of this study was to divide the lateral canthal rhytids into classified groups and describe their clinical characteristics and suitable treatments. Methods A total of 525 patients were included in the study. These patients were groups according to age and sex. Digital photographs of the subject's lateral canthal rhytids (lateral view) were taken and classified as to type (upper, lower, and bidirectional) and degree of direction. Results A total of 425 patients (81 %) exhibited the bidirectional type of lateral canthal rhytids. The lower directional type was noted on 75 patients (14.3 %), while only 25 patients (4.7 %) exhibited the upper directional type. In the 30s age group, only 50 % exhibited the bidirectional type. However, this rate increased to a 100 % in the 60 year-old and above group. There seems to be no relationship between the type of lateral canthal rhytids and sex. The degrees of the angle of wrinkles were statistically significant only in the 30s and 40s age groups. Conclusions We classified lateral canthal rhytids into three groups. This classification helps to decrease the complications of botulinum toxin by associating different treatments with the type of lateral canthal rhytids.