New sunscreens confer improved protection for photosensitive patients in the blue light region.
BACKGROUND
Some patients with photosensitivity disorders are sensitive to visible radiation. As current commercial sunscreens do not significantly absorb in this region, there is a lack of effective topical photoprotection. To meet this need a new range of sunscreens has been developed incorporating zinc oxide and pigmentary grade titanium dioxide as active ingredients.


OBJECTIVE
To determine the effectiveness of the new sunscreens in providing 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 commercial agents, were compared, and a new parameter, photosensitivity protection factor (PPF), was developed. This was used to predict the likely degree of protection the various sunscreens would provide for patients with photosensitivity extending into the visible region. In the second in vivo part of the study, patients with known visible (blue) light photosensitivity were tested using light at 430 +/- 30 nm and the protection factor (PF) at this 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, SPF 25) 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 protection for patients with sensitivity to visible light (blue light region).
Moseley
H
H
The Photobiology Unit, University of Dundee, Ninewells Hospital and Medical School, Dundee DD1 9SY, UK. H.Moseley@dundee.ac.uk
Cameron
H
H
MacLeod
T
T
Clark
C
C
Dawe
R
R
Ferguson
J
J
D000328:Adult; D000368:Aged; D002648:Child; D004890:Erythema / Q000517:prevention & control; D006801:Humans; D066298:In Vitro Techniques; D008027:Light; D008875:Middle Aged; D010787:Photosensitivity Disorders / Q000209:etiology / Q000517:prevention & control*; D011829:Radiation Dosage; D012542:Scattering, Radiation; D016037:Single-Blind Method; D013473:Sunscreening Agents / Q000627:therapeutic use*; D014466:Ultraviolet Rays
D013473:Sunscreening Agents