New sunscreens confer improved protection for photosensitive patients in the blue light region

Background Some patients with photosensitivity disorders are sensitive to v isible radiation. As current commercial sunscreens do not significantly abs orb in this region, there is a lack of effective topical photoprotection. T o meet this need a new range of sunscreens has been developed incorporating zinc oxide and pigmentary grade titanium dioxide as active ingredients. Objectives To determine the effectiveness of the new sunscreens in providin g protection for patients with visible radiation photosensitivity. Methods In the first part of this study, an in vitro transmission spectrum was obtained. The properties of the new sunscreens, as well as a range of c ommercial agents, were compared, and a new parameter, photosensitivity prot ection factor (PPF), was developed. This was used to predict the likely deg ree of protection the various sunscreens would provide for patients with ph otosensitivity extending into the visible region. In the second in vivo par t of the study, patients with known visible (blue) light photosensitivity w ere tested using light at 430 +/- 30 nm and the protection factor (PF) at t his wavelength was determined. Results Mean SD PPFs for the new sunscreens were between 5.4 +/-0.3 and 9.6 +/-0.3, compared with 4.1 +/-0.1 for Sun E45 (sun protection factor, SPF25 ) and 4.2 +/-0.1 for RoC Total (SPF 25). The derived in vivo PF for Sun E45 ranged between 1 and 4 (median 2). For the new sunscreens the range was 3 to >10 (median 8). Conclusions This study demonstrates that the new sunscreens do provide prot ection for patients with sensitivity to visible light (blue light region).