An estimated 20,000 surgeons in the U.S. are over 70--no more immune than the rest of us from weaker vision, slower hand-eye coordination or forgetfulness. Yet there’s not a clear system for telling a doctor it’s time to retire from surgery. Dr. Mark Katlic, chair of surgery at LifeBridge Health Sinai Hospital, has devised a two-day evaluation to test the physical and mental fitness of surgeons.He says a mandatory retirement age is not the answer. We also talk to Dr. Herbert Dardik, who resisted the testing but now thinks it’s needed.