Kearney Stephanie, O'Donoghue Lisa, Pourshahidi L Kirsty, Richardson Patrick M, Saunders Kathryn J
Optometry and Vision Science Research Group, University of Ulster, Coleraine, UK.
Northern Ireland Centre for Food and Health, University of Ulster, Coleraine, UK.
Ophthalmic Physiol Opt. 2016 Jul;36(4):359-69. doi: 10.1111/opo.12309.
Conjunctival ultraviolet autofluorescence (CUVAF) has been used in previous Southern Hemisphere myopia research as a marker for time spent outdoors. 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 measures, self-reported time spent outdoors and measures of dry eye.
Participants were recruited from University staff and students (n = 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 CUVAF area, average CUVAF pixel intensity per mm(2) and total CUVAF pixel intensity were analysed using MATLAB R2013a (The MathWorks Inc).
Of the 50 participants, 42% were classified as having dry eye. Self-reported sunglasses use was negatively associated with all CUVAF measures (Kruskal Wallis total CUVAF area, p = 0.04, ptrend = 0.03, average CUVAF pixel intensity p = 0.02, ptrend = 0.02, total CUVAF pixel intensity: p = 0.04, ptrend = 0.02). Time spent outdoors was positively associated with all CUVAF measures (Spearman's correlation coefficients, total CUVAF area: r = 0.37, p = 0.01, average CUVAF pixel intensity: r = 0.36, p = 0.01, total CUVAF pixel intensity: r = 0.37, p = 0.01) and remained significant when sunglasses use was controlled for (partial correlation, total CUVAF area: r = 0.32, p = 0.03, average CUVAF pixel intensity: r = 0.39, p = 0.01, total CUVAF pixel intensity: r = 0.39, p = 0.03). Neither CUVAF area nor intensity measures were associated with any dry eye measure (Ocular Surface Disease Index: all p ≥ 0.41, corneal staining: all p ≥ 0.38, McMonnies: all r ≤ 0.09 all p ≥ 0.52, slit lamp biomicroscopy: all r ≤ 0.20 all p ≥ 0.17, invasive tear break up time: all r ≤ -0.07 all p ≥ 0.31).
CUVAF area and intensity were 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.
结膜紫外线自发荧光（CUVAF）在先前南半球近视研究中被用作户外活动时间的标志物。在北半球，CUVAF作为户外活动时间指标的有效性尚待探索。目前尚不清楚CUVAF是代表紫外线暴露所致损伤还是干眼。这项横断面研究调查了CUVAF测量值、自我报告的户外活动时间与干眼测量值之间的关联。
研究对象招募自大学教职员工和学生（n = 50，年龄19 - 64岁；平均41岁）。无人正在使用局部眼用药物（干眼治疗药物除外）。参与者完成了阳光暴露和干眼问卷（眼表疾病指数和麦克莫尼问卷）。还使用裂隙灯生物显微镜检查和侵入性泪膜破裂时间评估了眼干情况。使用定制摄影系统采集左右眼颞侧和鼻侧结膜的图像。使用MATLAB R2013a（MathWorks公司）分析CUVAF总面积、每平方毫米平均CUVAF像素强度和CUVAF总像素强度。
50名参与者中，42%被归类为患有干眼。自我报告的太阳镜使用情况与所有CUVAF测量值呈负相关（Kruskal Wallis检验，CUVAF总面积，p = 0.04，趋势p = 0.03；平均CUVAF像素强度，p = 0.02，趋势p = 0.02；CUVAF总像素强度：p = 0.04，趋势p = 0.02）。户外活动时间与所有CUVAF测量值呈正相关（Spearman相关系数，CUVAF总面积：r = 0.37，p = 0.01；平均CUVAF像素强度：r =
0.36，p = 0.01；CUVAF总像素强度：r = 0.37，p = 0.01），在控制太阳镜使用情况后仍具有显著性（偏相关，CUVAF总面积：r = 0.32，p = 0.03；平均CUVAF像素强度：r = 0.
39，p = 0.01；CUVAF总像素强度：r = 0.39，p = 0.03）。CUVAF面积和强度测量值均与任何干眼测量值无关（眼表疾病指数：所有p≥0.41；角膜染色：所有p≥0.38；麦克莫尼问卷：所有r≤0.09，所有p≥0.52；裂隙灯生物显微镜检查：所有r≤0.20，所有p≥0.17；侵入性泪膜破裂时间：所有r≤ - 0.07，所有p≥0.31）。
CUVAF面积和强度与干眼的临床测量值无关。CUVAF面积和强度越大，与太阳镜佩戴频率越低和户外活动时间越长相关。如果考虑太阳镜佩戴情况，CUVAF可能在未来近视研究中成为户外活动时间的有用生物标志物。
