A new approach for the analysis of facial growth and age estimation: Iris ratio

The study of facial growth is explored in many fields of science, including anatomy, genetics, and forensics. In the field of forensics, it acts as a valuable tool for combating child pornography. The present research proposes a new method, based on relative measurements and fixed references of the human face—specifically considering measurements of the diameter of the iris (iris ratio)—for the analysis of facial growth in association with age in children and sub-adults. The experimental sample consisted of digital photographs of 1000 Brazilian subjects, aged between 6 and 22 years, distributed equally by sex and divided into five specific age groups (6, 10, 14, 18, and 22 year olds ± one month). The software package SAFF-2D® (Forensic Facial Analysis System, Brazilian Federal Police, Brazil) was used for positioning 11 landmarks on the images. Ten measurements were calculated and used as fixed references to evaluate the growth of the other measurements for each age group, as well the accumulated growth (6–22 years old). The Intraclass Correlation Coefficient (ICC) was applied for the evaluation of intra-examiner and inter-examiner reliability within a specific set of images. Pearson’s Correlation Coefficient was used to assess the association between each measurement taken and the respective age groups. ANOVA and Post-hoc Tukey tests were used to search for statistical differences between the age groups. The outcomes indicated that facial structures grow with different timing in children and adolescents. Moreover, the growth allometry expressed in this study may be used to understand what structures have more or less proportional variation in function for the age ranges studied. The diameter of the iris was found to be the most stable measurement compared to the others and represented the best cephalometric measurement as a fixed reference for facial growth ratios (or indices). The method described shows promising potential for forensic applications, especially as part of the armamentarium against crimes involving child pornography and child abuse.

[1]  A. Schmeling,et al.  Studies of the Chronological Course of Wisdom Tooth Eruption in a Black African Population , 2007, Journal of forensic sciences.

[2]  T. Paus,et al.  Automated Analysis of Craniofacial Morphology Using Magnetic Resonance Images , 2011, PloS one.

[3]  T. Riepert,et al.  Criteria for age estimation in living individuals , 2008, International Journal of Legal Medicine.

[4]  A. Schmeling,et al.  Studies of the chronological course of wisdom tooth eruption in a German population. , 2008, Journal of forensic and legal medicine.

[5]  V F Ferrario,et al.  Soft-tissue facial morphometry from 6 years to adulthood: a three-dimensional growth study using a new modeling. , 1999, Plastic and reconstructive surgery.

[6]  Juliane Freud,et al.  Anthropometric Facial Proportions In Medicine , 2016 .

[7]  J. Gayon,et al.  History of the Concept of Allometry , 2000 .

[8]  A. R. Vieira,et al.  ACTN3 R577X genotypes associate with Class II and deepbite malocclusions. , 2014, American journal of orthodontics and dentofacial orthopedics : official publication of the American Association of Orthodontists, its constituent societies, and the American Board of Orthodontics.

[9]  E. Salter,et al.  Craniofacial Anthropometry: Practical Measurement of the Head and Face for Clinical, Surgical, and Research Use , 1997 .

[10]  J. Prieto,et al.  The problem of aging human remains and living individuals: a review. , 2009, Forensic science international.

[11]  R. Bergman,et al.  Longitudinal study of cephalometric soft tissue profile traits between the ages of 6 and 18 years. , 2014, The Angle orthodontist.

[12]  Marco Grandi,et al.  The difficult issue of age assessment on pedo-pornographic material. , 2009, Forensic science international.

[13]  P. Castelein.  Facial growth. , 1971, Dental student.

[14]  A. Trussler.  Facial Geometry: Graphic Facial Analysis for Forensic Artists , 2008 .

[15]  Mehmet Yaşar İşcan,et al.  Forensic Analysis of the Skull , 2004 .

[16]  Jean-Marie Parel,et al.  Human ocular biometry. , 2012, Experimental eye research.

[17]  R. Ward,et al.  A Lack of Sexual Dimorphism in Width-to-Height Ratio in White European Faces Using 2D Photographs, 3D Scans, and Anthropometry , 2012, PloS one.

[18]  T. Baccetti,et al.  Duration of the pubertal peak in skeletal Class I and Class III subjects. , 2010, The Angle orthodontist.

[19]  Martin Evison,et al.  Computer-aided forensic facial comparison , 2010 .

[20]  J. Gayon,et al.  History of the Concept of Allometry1 , 2000 .

[21]  J. Borgstein,et al.  New insights into facial anthropometry in digital photographs using iris dependent calibration. , 2011, International Journal of Pediatric Otorhinolaryngology.

[22]  Steven N. Byers,et al.  Introduction to Forensic Anthropology: A Textbook , 2001 .

[23]  Christos Stavrianos,et al.  Facial Mapping: Review of Current Methods , 2012 .

[24]  G Geserick,et al.  Forensic age diagnostics of living people undergoing criminal proceedings. , 2004, Forensic science international.

[25]  Pasquale Poppa,et al.  Can facial proportions taken from images be of use for ageing in cases of suspected child pornography? A pilot study , 2011, International Journal of Legal Medicine.

[26]  L. Fishman.  Chronological versus skeletal age, an evaluation of craniofacial growth. , 1979, The Angle orthodontist.

[27]  M. Goldstein,et al.  Changes in dimensions and form of the face and head with age , 1936 .

[28]  C. Campobasso,et al.  Forensic age estimation of living individuals: a retrospective analysis. , 2009, Forensic science international.

[29]  P. M. Garamendi,et al.  Reliability of the methods applied to assess age minority in living subjects around 18 years old. A survey on a Moroccan origin population. , 2005, Forensic science international.

[30]  G. Krovitz,et al.  Common patterns of facial ontogeny in the hominid lineage , 2002, The Anatomical record.

[31]  Paul W Major,et al.  Use of skeletal maturation based on hand-wrist radiographic analysis as a predictor of facial growth: a systematic review. , 2009, The Angle orthodontist.

[32]  J. Huxley,et al.  Terminology of Relative Growth , 1936, Nature.