Lab color measurements of Ota nevus, freckles and melasma

Abstract

Objective Lab color mode can be used to digitize the color. This study explores the possibility of using Lab model to measure facial pigmentations. Methods Lab color model was used to measure the normal skin and three common clinical pigmentations (Ota nevus, freckles and melasma). We also analyzed the characteristics and assessed the data changes after the treatment. Results Average L, a and b values were 54.4, 13.8 and 19.0 in normal skin, 34.6, 5.17 and 6.9 in Ota nevus, 43.25, 16.15 and 23.05 in freckles and 40.5, 16.8 and 23.35 in melasma, respectively. The Lab values of freckles and melasma were close. The order of L value was: normal skin > freckle > melasma > Ota nevus; the order of value of a and b was: melasma > freckle > normal skin > Ota nevus. After treatment, the Lab values gradually tended to be the values of normal skin. Conclusions The Lab color mode can be used as a digital description method for skin color and facial pigmentation, which provides an objective measure for clinical research. Key words: Nevus of Ota; Freckles; Chloasma; Melanosomes; Lab color model; Digital description