title: Involutional ectropion and entropion: clinicopathologic correlation between horizontal eyelid laxity and eyelid extracellular matrix.
abstract: OBJECTIVE
  To investigate the clinicopathologic correlation between horizontal eyelid laxity and extracellular matrix components, such as collagen and elastic fibers, in involutional ectropion and entropion. Another goal was to compare the differences between involutional ectropion and entropion in regard to extracellular matrix content using computer-assisted morphometry.
  
  
  METHODS
  This clinicopathologic study included 20 consecutive patients with involutional ectropion (group 1) and 20 consecutive patients with involutional entropion (group 2). The pinch test was performed to measure horizontal eyelid laxity in both groups. Full-thickness eyelid biopsy specimens were examined by light microscopy and computer-assisted morphometry. The Mann-Whitney U test, the Pearson chi-square test, the Pearson correlation coefficient calculation, and a linear regression analysis were performed.
  
  
  RESULTS
  All sections of specimens from patients in groups 1 and 2 revealed abnormal collagen and elastic fibers. The Pearson correlation coefficient revealed a significant negative correlation between horizontal eyelid laxity and extracellular matrix content in the eyelid skin, the pretarsal orbicularis oculi muscle, the perimeibomian tarsal stroma, and the intermeibomian tarsal stroma. Linear regression demonstrated that horizontal eyelid laxity is dependent upon extracellular matrix components in all eyelid regions. Collagen fiber content was significantly increased in specimens from patients in group 1 compared with specimens from patients in group 2.
  
  
  CONCLUSIONS
  The present findings suggest that a reduction of collagen and elastic fibers may contribute to the development of excessive horizontal eyelid laxity in patients with involutional ectropion and entropion of the lower eyelid.
authors.affiliation: Department of Ophthalmology and Vision Institute, Federal University of São Paulo, Brazil. renato.damasceno@unifesp.br
authors.forename: Renato Wendell
authors.initials: RW
authors.lastname: Damasceno
authors.forename: Midori Hentona
authors.initials: MH
authors.lastname: Osaki
authors.forename: Paulo Elias Correa
authors.initials: PE
authors.lastname: Dantas
authors.forename: Rubens
authors.initials: R
authors.lastname: Belfort
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001706:Biopsy; D003094:Collagen / Q000032:analysis; D004483:Ectropion / Q000473:pathology*; D004548:Elasticity; D004549:Elastin / Q000032:analysis; D004774:Entropion / Q000473:pathology*; D005109:Extracellular Matrix / Q000378:metabolism*; D005143:Eyelids / Q000473:pathology*; D005260:Female; D006801:Humans; D008297:Male; D012044:Regression Analysis
chemical_list: D003094:Collagen; D004549:Elastin