[1] Univ Nottingham, Sch Phys & Astron, Univ Pk, Nottingham NG7 2RD, England
[2] Erasmus MC, Dept Dermatol, NL-3015 GD Rotterdam, Netherlands
[3] Nottingham Univ Hosp, Nottingham NHS Treatment Ctr, Lister Rd, Nottingham NG7 2FT, England
[4] Royal Holloway Univ London, Math Dept, Egham TW20 OEX, Surrey, England
[5] Erasmus MC, Dept Dermatol, Ctr Opt Diagnost & Therapy, NL-3015 GD Rotterdam, Netherlands
[6] RiverD Int BV, Marconistr 16, NL-3029 AK Rotterdam, Netherlands
[7] Nottingham Univ Hosp NHS Trust, Ctr Evidence Based Dermatol, QMC Campus,Derby Rd, Nottingham NG7 2UH, England