Detailed Instructions: Given a passage with a question and an answer to that question, classify if the answer actually answers the question into 'yes' or 'no'. Output 'yes' if the answer answers the question and output 'no' if the answer does not answer the question.
Problem:Question: Does psoralen plus ultraviolet A increase the risk of cataracts : a 25-year prospective study?
Answer: Our cohort principally enrolled middle-aged or older patients so our data do not permit us to assess the effects of PUVA on the eyes of younger persons.
Solution:
no