Patient kept diabetes hidden for 19 years
Nearly discovered; then disappeared for 9 years
These are some highlights from the investigation by the National Transportation Safety Board (NTSB) in Washington, DC, concerning the train wreck involving engineer John DeCurtis:
• The engineer’s personal physician, not the occupational medicine specialist, told the NTSB that the man had been a noninsulin-dependent (type II) diabetic for 19 years and, as a result, suffered from peripheral vascular disease. She said she had counseled him about his condition and treated him with various oral medications since 1982. He had been essentially asymptomatic until 1987.
• In addition to being colorblind, DeCurtis’ last eye examinations indicated that he had little vision remaining in his left eye. His left eye vision was 20/400 with correction. The vision in his right eye varied from 20/30 to 20/70 with correction.
• Panretinal photocoagulation surgery had been performed to treat the proliferative retinopathy in the engineer’s right eye as late as January 1996, two weeks before the accident.
• "The contract physician’s failure to comply with the Dvorine nomenclature testing protocol resulted in erroneous certification of the train 1254 engineer for duty." The nomenclature test instructions warn the user that "many colorblind individuals learn to name the colors correctly by brightness instead of their hue," so it should not be used to diagnose colorblindness.
• Despite "the doctor’s error," the NTSB says the testing and certification could be considered compliant with federal certification standards, which only state that the patient must be able to distinguish the colors of signals. Even if there are indications of colorblindness, the medical examiner can certify the engineer if he or she believes the engineer can safely operate a locomotive.
• Federal regulations do not specify how to test for colorblindness. Different railroads and other industries use various tests. "In addition to the Dvorine nomenclature test, many other available tests are equally undesirable," state the regulations.