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stephanie kearney, Kathryn Saunders, Lisa O'Donoghue, Kirsty Pourshahidi, Patrick Richardson; The use of conjunctival ultraviolet autofluorescence (CUVAF) as an indicator of time spent outdoors. Invest. Ophthalmol. Vis. Sci. 2016;57(12):2493.
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© ARVO (1962-2015); The Authors (2016-present)
CUVAF has been used in previous Southern Hemisphere myopia research as a marker for time spent outdoors1,2. The validity of CUVAF as an indicator of time spent outdoors is yet to be explored in the Northern Hemisphere. It is unclear if CUVAF represents damage attributed to UV exposure or dry eye. This cross-sectional study investigated the association between CUVAF intensity and area, self-reported time spent outdoors and measures of dry eye.
Images of the temporal and nasal conjunctiva from the right and left eye of 50 participants were captured using a bespoke photography system. Participants (19-64yrs;mean 41) were recruited from University staff and students. None were using topical ocular medications. All completed questionnaires to elicit information on dry eye (Ocular Surface Disease Index (OSDI) and McMonnies) and time spent outdoors (sun exposure questionnaire3). Ocular dryness was assessed using slit lamp biomicroscopy and invasive tear break up time (ITBUT). The area and intensity of CUVAF fluorescence (fig1) was analysed using MATLAB R2013a (The MathWorks Inc.). As CUVAF intensity and area were not normally distributed, non-parametric statistical analyses were performed.
Of the 50 participants, 42% were classified as having dry eye. Self-reported sunglass use was negatively associated with CUVAF area and intensity (Kruskal Wallis p=0.042, ptrend=0.026 and p=0.022, ptrend= 0.023, respectively). Time spent outdoors was positively associated with CUVAF area and intensity (Spearman’s corr. r=0.37, p=0.0081 and r=0.36, p=0.011, respectively) and remained significant when sunglass use was controlled for (partial corr. both p<0.016). Neither CUVAF area nor intensity was associated with any dry eye measures (all p≥0.17).
CUVAF was not associated with clinical measures of dry eye. Greater CUVAF area and intensity were associated with wearing sunglasses less frequently and spending more time outdoors. If sunglass wear is accounted for, CUVAF may be a useful biomarker of time spent outdoors in future myopia studies.References:1. Sherwin JC et al. Invest Ophthalmol Vis Sci 2012;53(8):4363-4370.2. McKnight CM et al. Am J Ophtalmol 2014;158(5):1079-1085.3. Cashman KD et al. Am J Clin Nutr 2009;89(5):1366-1374.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.
Fig 1. Example of a novel CUVAF image
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