Usefulness of a Narrow-Band Reflectance Spectrophotometer in Evaluating Effects of Depigmenting Treatment

Abstract. As a depigmenting treatment, combined topical ap-plications of all-trans retinoic acid (atRA) aqueous gel and 5% hydroquinone, 7 % lactic acid ointment were used for Oriental patients with hyperpigmented skin lesions such as senile len-tigines and nevus spilus. A narrow-band reflectance spectro-photometer and a tristimulus colorimeter were used to evaluate objectively the intensity of pigmentation and erythema at each clinical visit. L*, a*, and b * values measured with a tristimulus colorimeter (Chroma Meter CR-300) enabled the evaluation of erythema but not pigmentation. On the other hand, the melanin and hemoglobin values measured with a narrow-band reflec-tance spectrophotometer (Mexameter MX-16) expressed both erythema and pigmentation well. It was revealed that, in our bleaching protocol, the narrow-band reflectance spectropho-tometer was quite useful for estimating accurately the intensit