Description:
<jats:title>Abstract</jats:title><jats:sec><jats:title>Purpose</jats:title><jats:p>Conjunctival ultraviolet autofluorescence (<jats:styled-content style="fixed-case">CUVAF</jats:styled-content>) has been used in previous Southern Hemisphere myopia research as a marker for time spent outdoors. The validity of <jats:styled-content style="fixed-case">CUVAF</jats:styled-content> as an indicator of time spent outdoors is yet to be explored in the Northern Hemisphere. It is unclear if <jats:styled-content style="fixed-case">CUVAF</jats:styled-content> represents damage attributed to <jats:styled-content style="fixed-case">UV</jats:styled-content> exposure or dry eye. This cross‐sectional study investigated the association between <jats:styled-content style="fixed-case">CUVAF</jats:styled-content> measures, self‐reported time spent outdoors and measures of dry eye.</jats:p></jats:sec><jats:sec><jats:title>Methods</jats:title><jats:p>Participants were recruited from University staff and students (<jats:italic>n</jats:italic> = 50, 19–64 years; mean 41). None were using topical ocular medications (with the exception of dry eye treatments). Sun exposure and dry eye questionnaires (Ocular Surface Disease Index and McMonnies) were completed by the participant. Dryness was also assessed using slit lamp biomicroscopy and invasive tear break up time. Images of the temporal and nasal conjunctiva from the right and left eye were captured using a bespoke photography system. The total <jats:styled-content style="fixed-case">CUVAF</jats:styled-content> area, average <jats:styled-content style="fixed-case">CUVAF</jats:styled-content> pixel intensity per mm<jats:sup>2</jats:sup> and total <jats:styled-content style="fixed-case">CUVAF</jats:styled-content> pixel intensity were analysed using <jats:styled-content style="fixed-case">MATLAB</jats:styled-content> R2013a (The MathWorks Inc).</jats:p></jats:sec><jats:sec><jats:title>Results</jats:title><jats:p>Of the 50 participants, 42% were classified as having dry eye. Self‐reported sunglasses use was negatively associated with all <jats:styled-content style="fixed-case">CUVAF</jats:styled-content> measures (Kruskal Wallis total <jats:styled-content style="fixed-case">CUVAF</jats:styled-content> area, <jats:italic>p</jats:italic> = 0.04, <jats:italic>p</jats:italic><jats:sub>trend</jats:sub> = 0.03, average <jats:styled-content style="fixed-case">CUVAF</jats:styled-content> pixel intensity <jats:italic>p</jats:italic> = 0.02, <jats:italic>p</jats:italic><jats:sub>trend</jats:sub> = 0.02, total <jats:styled-content style="fixed-case">CUVAF</jats:styled-content> pixel intensity: <jats:italic>p</jats:italic> = 0.04, <jats:italic>p</jats:italic><jats:sub>trend</jats:sub> = 0.02). Time spent outdoors was positively associated with all <jats:styled-content style="fixed-case">CUVAF</jats:styled-content> measures (Spearman's correlation coefficients, total <jats:styled-content style="fixed-case">CUVAF</jats:styled-content> area: <jats:italic>r</jats:italic> = 0.37, <jats:italic>p</jats:italic> = 0.01, average <jats:styled-content style="fixed-case">CUVAF</jats:styled-content> pixel intensity: <jats:italic>r</jats:italic> = 0.36, <jats:italic>p</jats:italic> = 0.01, total <jats:styled-content style="fixed-case">CUVAF</jats:styled-content> pixel intensity: <jats:italic>r</jats:italic> = 0.37, <jats:italic>p</jats:italic> = 0.01) and remained significant when sunglasses use was controlled for (partial correlation, total <jats:styled-content style="fixed-case">CUVAF</jats:styled-content> area: <jats:italic>r</jats:italic> = 0.32, <jats:italic>p</jats:italic> = 0.03, average <jats:styled-content style="fixed-case">CUVAF</jats:styled-content> pixel intensity: <jats:italic>r</jats:italic> = 0.39, <jats:italic>p</jats:italic> = 0.01, total <jats:styled-content style="fixed-case">CUVAF</jats:styled-content> pixel intensity: <jats:italic>r</jats:italic> = 0.39, <jats:italic>p</jats:italic> = 0.03). Neither <jats:styled-content style="fixed-case">CUVAF</jats:styled-content> area nor intensity measures were associated with any dry eye measure (Ocular Surface Disease Index: all <jats:italic>p</jats:italic> ≥ 0.41, corneal staining: all <jats:italic>p</jats:italic> ≥ 0.38, McMonnies: all <jats:italic>r</jats:italic> ≤ 0.09 all <jats:italic>p</jats:italic> ≥ 0.52, slit lamp biomicroscopy: all <jats:italic>r</jats:italic> ≤ 0.20 all <jats:italic>p</jats:italic> ≥ 0.17, invasive tear break up time: all <jats:italic>r</jats:italic> ≤ −0.07 all <jats:italic>p</jats:italic> ≥ 0.31).</jats:p></jats:sec><jats:sec><jats:title>Conclusions</jats:title><jats:p><jats:styled-content style="fixed-case">CUVAF</jats:styled-content> area and intensity were not associated with clinical measures of dry eye. Greater <jats:styled-content style="fixed-case">CUVAF</jats:styled-content> area and intensity were associated with wearing sunglasses less frequently and spending more time outdoors. If sunglass wear is accounted for, <jats:styled-content style="fixed-case">CUVAF</jats:styled-content> may be a useful biomarker of time spent outdoors in future myopia studies.</jats:p></jats:sec>