UV light set-ups for vitiligo photography, a comparative study on image quality and ease of use

Background: Ultraviolet (UV) light is an essential tool to assess the extent, spreading and staging of vitiligo. Different UV light set-ups are used for vitiligo photography, including the following: (i) hand-held Wood’s lamps; (ii) soft boxes with UV lamps; (iii) UV flash attached to the camera; and (iv) high output UV flash. Objective: Our objective was to compare UV light set-ups for vitiligo photography regarding image quality and ease of use. Methods: Patients with vitiligo lesions with unclear borders were included. Two images were made with all four UV set-ups per patient, for a large and a small area. Image quality was scored separately by three blinded vitiligo experts on five criteria: overall quality, clearness of borders, contrast and sharpness and for larger areas the shadows. The two professional medical photographers were asked to score the ease of use for each set-up. Results: A total of 88 photos were assessed from 11 patients. For larger areas, the frequency of a ‘good’ or ‘very good’ overall quality rating was 12.1% (Wood’s), 6.1% (soft boxes), 15.2% (camera flash) and 78.8% (high output flash). For smaller areas, the score ‘good’ or ‘very good’ was given to 54.5%, 3%, 66.6% and 84.8% in the same order. For the shadow criteria, each set-up scored below 40% on a 'good' or 'very good' score. The high output flash was scored as most easy to use by the photographers. Conclusion: When comparing four different UV light set-ups for vitiligo photography, we concluded that the UV set-ups strongly influenced the quality scores of the obtained images. The high output flash scored best for both small and large areas and for ease of use. For small areas, Wood’s lamp and camera flash were acceptable. All set-ups scored badly for shadows, and more research is needed to find the optimal exposure to avoid shadows.