title: Distribution of conjunctival ultraviolet autofluorescence in a population-based study: the Norfolk Island Eye Study.
abstract: OBJECTIVE
  The objective of this study was to describe the distribution of conjunctival ultraviolet autofluorescence (UVAF) in an adult population.
  
  
  METHODS
  We conducted a cross-sectional, population-based study in the genetic isolate of Norfolk Island, South Pacific Ocean. In all, 641 people, aged 15 to 89 years, were recruited. UVAF and standard (control) photographs were taken of the nasal and temporal interpalpebral regions bilaterally. Differences between the groups for non-normally distributed continuous variables were assessed using the Wilcoxon-Mann-Whitney ranksum test. Trends across categories were assessed using Cuzick's non-parametric test for trend or Kendall's rank correlation τ.
  
  
  RESULTS
  Conjunctival UVAF is a non-parametric trait with a positively skewed distribution. Median amount of conjunctival UVAF per person (sum of four measurements; right nasal/temporal and left nasal/temporal) was 28.2 mm(2) (interquartile range 14.5-48.2). There was an inverse, linear relationship between UVAF and advancing age (P<0.001). Males had a higher sum of UVAF compared with females (34.4 mm(2) vs 23.2 mm(2), P<0.0001). There were no statistically significant differences in area of UVAF between right and left eyes or between nasal and temporal regions.
  
  
  CONCLUSIONS
  We have provided the first quantifiable estimates of conjunctival UVAF in an adult population. Further data are required to provide information about the natural history of UVAF and to characterise other potential disease associations with UVAF. UVR protective strategies should be emphasised at an early age to prevent the long-term adverse effects on health associated with excess UVR.
authors.affiliation: Centre for Eye Research Australia, University of Melbourne, Department of Ophthalmology, Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia.
authors.forename: J C
authors.initials: JC
authors.lastname: Sherwin
authors.forename: A W
authors.initials: AW
authors.lastname: Hewitt
authors.forename: L S
authors.initials: LS
authors.lastname: Kearns
authors.forename: M T
authors.initials: MT
authors.lastname: Coroneo
authors.forename: L R
authors.initials: LR
authors.lastname: Griffiths
authors.forename: D A
authors.initials: DA
authors.lastname: Mackey
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D003228:Conjunctiva / Q000528:radiation effects*; D003430:Cross-Sectional Studies; D005260:Female; D005453:Fluorescence; D006801:Humans; D008297:Male; D008542:Melanesia; D008875:Middle Aged; D017678:Sex Distribution; D018709:Statistics, Nonparametric; D014466:Ultraviolet Rays / Q000009:adverse effects; D055815:Young Adult