title: Characterization of Normal Mediolateral Angular Direction of Lower Eyelid Eyelashes in Different Age Groups.
abstract: OBJECTIVE
  To characterize the normal eyelash mediolateral angular direction of the lower eyelid in different age groups.
  
  
  METHODS
  Sixty patients were divided into 3 groups: G1 - 6 to 12 years; G2 - 20 to 35; and G3 - 60 to 85. Digital photographs were obtained and eyelids were divided in lateral, central, and medial portions. Eyelash mediolateral angular direction relative to a baseline was measured and data were compared between portions and groups.
  
  
  RESULTS
  The mean eyelash mediolateral angular direction in the medial portion were: G1: 133.79° ± 17.56° SD; G2: 137.74° ± 10.5° SD; and G3: 116.05° ± 26.71° SD. The mean difference in angle between G1 and G3 was 17.74° (p = 0.015) and between G2 and G3 was 21.69° (p = 0.000). The mean eyelash mediolateral angular direction in central portion were: G1: 64.36° ± 12.58° SD; G2: 77.07° ± 12.17° SD; and G3: 84.9° ± 18.48° SD. The mean difference between Group 1 and 2 was 12.71° (p = 0.001) and between Group 1 and 3 was 20.54° (p = 0.000). The mean eyelash mediolateral angular direction in the lateral portion were: Group 1: 40.57° ± 6.78° SD; Group 2: 37.21° ± 5.69° SD; and Group 3: 38.48° ± 8.35° SD.
  
  
  CONCLUSIONS
  This study identified that lashes in the lateral portion of lower eyelid tend to maintain the same angular position throughout life. On the central and medial portions it tends to approach a 90° angle with age. The authors believe that this modification throughout life may be related to factors, such as involutional horizontal eyelid laxity and orbicular muscle modifications.
authors.affiliation: *Professor of the Department of Ophthalmology and Otolaryngology of Universidade Federal do Rio Grande do Sul School of Medicine - UFRGS/Hospital de Clínicas de Porto Alegre; †Ophthalmology Resident, and ‡Oculoplastic Fellow - Hospital de Clínicas de Porto Alegre, Porto Alegre, RS, Brazil.
authors.forename: Fernando
authors.initials: F
authors.lastname: Procianoy
authors.forename: Taís B
authors.initials: TB
authors.lastname: Mendonça
authors.forename: Cristiane A
authors.initials: CA
authors.lastname: Bins
authors.forename: Martha P L
authors.initials: MP
authors.lastname: Lang
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D002648:Child; D005140:Eyelashes / Q000033:anatomy & histology*; D005143:Eyelids / Q000033:anatomy & histology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010781:Photography; D011446:Prospective Studies; D055815:Young Adult