Stephanie Kearney1, Lisa O'Donoghue1, Laura K Pourshahidi2, Patrick Richardson1, Eamon Laird3, Martin Healy4,5, Kathryn J Saunders1. 1. Department of Optometry and Vision Science, Optometry and Vision Science Research Group, University of Ulster, Coleraine, UK. 2. Department of Biomedical Sciences, Nutrition Innovation Centre for Food and Health, University of Ulster, Coleraine, UK. 3. Department of Biochemistry and Immunology, Trinity College Dublin, Dublin, Ireland. 4. School of Medicine, Trinity College Dublin, Dublin, Ireland. 5. Department of Biochemistry, St James's Hospital, Dublin, Ireland.
Abstract
BACKGROUND: Conjunctival ultraviolet autofluorescence (CUVAF) has been used as a biomarker of time spent outdoors. Smaller CUVAF area is associated with myopia in southern hemisphere cohorts. Further research is required to determine if this association is replicated in northern latitudes and whether average CUVAF intensity is a valuable metric. This prospective study explored the association between myopia, CUVAF (area and intensity) and additional indicators of sun exposure (vitamin D3 and self-reported sun exposure preferences) across seasons at a location of 55° north. METHODS: Young adults (age 18-20) provided blood samples biannually (March/April and September/October) over an 18-month period (four phases) for the assessment of 25-hydroxyvitamin D (25(OH)D3 ) concentrations (liquid chromatography-tandem mass spectrometry). CUVAF (total area, average intensity) and self-reported sun exposure preferences were recorded at each phase. Axial length and corneal radius were measured. Refractive error was measured by autorefractor and spherical equivalent refraction used to classify participants into refractive groups: myopic (spherical equivalent refraction ≤ -0.50 DS) or non-myopic. RESULTS: Fifty-four participants (24 myopes, 30 non-myopes) participated. CUVAF area was negatively associated with the presence of myopia (odds ratio = 0.94, 95 per cent confidence interval = 0.90-0.98, p = 0.002). Myopes = 4.5 mm2 (interquartile range [IQR] 0.95-6.4 mm2 ), non-myopes = 7.0 mm2 (IQR = 2.0-10.7 mm2 ). No significant association was found between CUVAF intensity and refractive group (p = 0.17). There was no significant association between sun exposure preferences or serum concentration of 25(OH)D3 and refractive status (all p ≥ 0.21). CUVAF measures were not associated with ocular biometry measures (all p ≥ 0.084). CUVAF area was unaffected by season (all p ≥ 0.45) and variations in CUVAF area over the study period did not exceed the repeatability of the measurement technique. CONCLUSION: Myopia was associated with smaller areas of CUVAF indicative of less cumulative ultraviolet-B exposure. These findings suggest that CUVAF measures are a useful, non-invasive biomarker of the time spent outdoors in adults in northern hemisphere populations.
BACKGROUND: Conjunctival ultraviolet autofluorescence (CUVAF) has been used as a biomarker of time spent outdoors. Smaller CUVAF area is associated with myopia in southern hemisphere cohorts. Further research is required to determine if this association is replicated in northern latitudes and whether average CUVAF intensity is a valuable metric. This prospective study explored the association between myopia, CUVAF (area and intensity) and additional indicators of sun exposure (vitamin D3 and self-reported sun exposure preferences) across seasons at a location of 55° north. METHODS: Young adults (age 18-20) provided blood samples biannually (March/April and September/October) over an 18-month period (four phases) for the assessment of 25-hydroxyvitamin D (25(OH)D3 ) concentrations (liquid chromatography-tandem mass spectrometry). CUVAF (total area, average intensity) and self-reported sun exposure preferences were recorded at each phase. Axial length and corneal radius were measured. Refractive error was measured by autorefractor and spherical equivalent refraction used to classify participants into refractive groups: myopic (spherical equivalent refraction ≤ -0.50 DS) or non-myopic. RESULTS: Fifty-four participants (24 myopes, 30 non-myopes) participated. CUVAF area was negatively associated with the presence of myopia (odds ratio = 0.94, 95 per cent confidence interval = 0.90-0.98, p = 0.002). Myopes = 4.5 mm2 (interquartile range [IQR] 0.95-6.4 mm2 ), non-myopes = 7.0 mm2 (IQR = 2.0-10.7 mm2 ). No significant association was found between CUVAF intensity and refractive group (p = 0.17). There was no significant association between sun exposure preferences or serum concentration of 25(OH)D3 and refractive status (all p ≥ 0.21). CUVAF measures were not associated with ocular biometry measures (all p ≥ 0.084). CUVAF area was unaffected by season (all p ≥ 0.45) and variations in CUVAF area over the study period did not exceed the repeatability of the measurement technique. CONCLUSION:Myopia was associated with smaller areas of CUVAF indicative of less cumulative ultraviolet-B exposure. These findings suggest that CUVAF measures are a useful, non-invasive biomarker of the time spent outdoors in adults in northern hemisphere populations.
Authors: Gareth Lingham; Seyhan Yazar; Robyn M Lucas; John P Walsh; Kun Zhu; Michael Hunter; Ee Mun Lim; Brian R Cooke; David A Mackey Journal: Transl Vis Sci Technol Date: 2019-01-22 Impact factor: 3.283
Authors: Lin Leng; Jiafan Zhang; Sen Xie; Wenzhi Ding; Rongyuan Ji; Yuyin Tian; Keli Long; Hongliang Yu; Zhen Guo Journal: Int J Gen Med Date: 2021-08-28