Conjunctival ultraviolet autofluorescence (CUVAF) can show clinicians how much time patients spend outdoors, and that can translate into a myopia monitoring tool, according to researchers. A group of European researchers assert their study, published in Clinical and Experimental Optometry, shows that the smaller a patient’s area of CUVAF, the more time they spend outdoors.

“These findings suggest that CUVAF measures are a useful, non-invasive biomarker of the time spent outdoors in adults in northern hemisphere populations,” the study reads.

To determine that, the team looked at 54 patients (24 with myopia and 30 without) and examined their CUVAF as well as self-reported sun exposure preferences. They also took the patients’ blood samples to assess their vitamin D₃ concentrations. While they found no significant association between sun exposure preferences or serum concentration of vitamin D₃ and refractive status, they did find that, in nearly every case, CUVAF area was negatively associated with myopia.

The researchers concluded that the less cumulative ultraviolet-B exposure from sunlight, the more likely patients were to be myopic.