This study has shown the Durham MED tester to be a convenient, valid and reproducible method for determining patient MED values prior to narrowband UVB phototherapy when used under carefully controlled lighting, by experienced observers.

This study has revealed considerable variability in the practice of emollient use before phototherapy treatments. Although the majority of centres included in this study did not routinely use emollients, almost one third did. Our in vitro measurement of 30 emollients revealed marked variation in UV transmission, with many emollients blocking sufficient UV to affect the response to therapy.

UV transmission for sunglasses and contact lenses is lower compared with samples tested 10 years ago. All samples of glasses, goggles and visors tested provided adequate protection in the UV range according to published arbitrary limits of acceptability. Most contact lenses did not provide significant UV protection in the UVA range.