title: A quantitative evaluation method using processed optical images and analysis of age-dependent changes on nasolabial lines.
abstract: OBJECTIVE
  Nasolabial lines (NL) and wrinkles of the face are major features of aging. Wrinkles have been studied widely by morphological methods using 3-dimensional (3D) photographic analysis instrument, but NL were evaluated by visual scoring usually. To evaluate NL quantitatively, another method is needed. This study is purposed to find out quantitative method for evaluation of NL.
  
  
  METHODS
  One hundred Korean female subjects aged 20 to 60 were recruited in this study. Facial image was taken using light source adjusted VISIA-CR(®) and 3-dimensional wrinkle depth on the NL area was evaluated by Phase shift rapid in vivo measuring of human skin (PRIMOS(®)). The pixel number of NL area and the angle were obtained using processed images. The severity of NL was assessed by visual score. Skin elasticity was measured by Cutometer(®) MPA580. Statistical significance was determined at P < 0.05.
  
  
  RESULTS
  The optical images obtained by light source adjusted VISIA-CR(®) were easy to distinguish NL and significantly increased age-dependently. And three parameters of elasticity (R2, R5, and R7) on NL area were gradually decreased with age. The Pearson correlation coefficient was -0.756 (P < 0.01) between R7 parameter and ages. Also the pixel number of NL area, angle, wrinkle depth on the NL area (Ra), and visual score were decreased elasticity-dependently. The pixel number of NL area was highly related to Ra (r = 0.567, P < 0.01) and visual score (r = 0.647, P < 0.01).
  
  
  CONCLUSIONS
  This study has shown that NL severity is related to decrease of dermal elasticity and age using quantitative new method by processing optical images.
authors.affiliation: AMORE PACIFIC Corporation/R&D CENTER, Yongin-Si Gyeonggi-do, Korea.
authors.forename: Sue Im
authors.initials: SI
authors.lastname: Jang
authors.forename: Eun Joo
authors.initials: EJ
authors.lastname: Kim
authors.forename: Hyeokgon
authors.initials: H
authors.lastname: Park
authors.forename: Hyun Jung
authors.initials: HJ
authors.lastname: Kim
authors.forename: Jang Mi
authors.initials: JM
authors.lastname: Suk
authors.forename: Beom Joon
authors.initials: BJ
authors.lastname: Kim
authors.forename: John Hwan
authors.initials: JH
authors.lastname: Lee
authors.forename: Hae Kwang
authors.initials: HK
authors.lastname: Lee
mesh_terms: D000328:Adult; D000465:Algorithms; D046169:Dermoscopy / Q000379:methods*; D055119:Elastic Modulus / Q000502:physiology; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008875:Middle Aged; D009666:Nose / Q000033:anatomy & histology / Q000502:physiology; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D015595:Skin Aging / Q000473:pathology* / Q000502:physiology*; D055815:Young Adult
keywords: NL angle; PRIMOS; aging; elasticity; nasolabial lines; optical images; pixel number of NL area; visual score