The Fitzpatrick scale (also Fitzpatrick skin typing test or Fitzpatrick phototype scale) is a numerical classification schema for human skin colour. It was developed in 1975 by American dermatologist Thomas B. Fitzpatrick, to estimate the response of different types of skin to ultraviolet (UV) light. It was initially developed based on skin colour to measure the correct dose of UVA for PUVA therapy, and when the initial testing based only on hair and eye colour resulted in too high UVA doses for some, it was altered to be based on the patient’s reports of how their skin responds to the sun; it was also extended to a wider range of skin types. The Fitzpatrick scale remains a recognized tool for dermatological research into human skin pigmentation.