A recent study investigated the utility of conjunctival ultraviolet autofluorescence as a biomarker for outdoor activity and its inverse relationship with myopia in children. The findings suggested this biomarker could offer a reliable, objective method to assess sunlight exposure and predict myopia risk, particularly in pediatric populations.
The study compared conjunctival ultraviolet autofluorescence (CUVAF) areas in children with and without myopia who visited Clínica Universidad de Navarra—a university hospital in Spain. Participants were excluded if they had amblyopia, congenital myopia, general ophthalmic disease, and any conjunctival alteration that might affect the measurement of the CUVAF area. Participants included 263 children aged 6 to 17 years, 213 of whom had myopia plus 50 controls. Myopic participants were further divided into low (M1), moderate (M2), and high myopia (HM) groups based on spherical equivalent.
CUVAF areas were then quantified using ultraviolet autofluorescence imaging. Additional data collected included axial length, central corneal radius, refractive error, weekly outdoor activity (OA), and near vision activity hours.
The researchers found that mean CUVAF area was significantly smaller in myopic children (0.33 ± 0.72 mm²) compared to controls (0.78 ± 1.22 mm²), and CUVAF absence was more common in myopic children, particularly in M2 and HM groups, with odds ratios (OR) of 4.96 and 4.25, respectively. CUVAF area increased with age, with significant differences noted between children under and over 12 years of age. Specifically, the mean CUVAF-area was 0.60 ± 1.00 mm2 in the older group and 0.12 ± 0.41 mm2 in the younger group. Older children also showed stronger correlations between CUVAF areas and reduced myopia risk, which suggested a cumulative effect of UV exposure, the researchers noted. According to their article published in Frontiers in Medicine, “a statistically significant difference is obtained when we separate the groups according to the degree of myopia, demonstrating how the CUVAF-area decreases as the degree of myopia increases.”
Myopic children spent fewer hours outdoors weekly (10.81 ± 4.18) compared to controls (14.28 ± 5.69), and the researchers observed a positive trend between greater OA hours and larger CUVAF areas, although this trend was not statistically significant.
CUVAF demonstrated moderate discriminative ability for identifying myopia risk. Its sensitivity was 0.71 and specificity was 0.52. It had the highest predictive accuracy for high myopia (AUC = 0.77 and sensitivity = 0.89).
While axial length has been linked to myopia development and previous studies have sought to correlate CUVAF area with it, only a significant correlation with spherical equivalent has been found so far, the researchers described. A statistically significant correlation has also been found between CUVAF and the relationship between axial length and corneal curvature radius. This relationship, the researchers explained, suggests “that sunlight exposure indeed affects the balance between ocular optical power and axial length, encompassing both refractive and axial myopia origins. It could be interesting to evaluate this parameter in a larger sample, and even in adult population, since its possible impact has not been previously analyzed.”
A full list of author disclosures can be found in the published research.
