title: The effect of abnormal colour vision on the ability to identify and outline coloured clinical signs and to count stained bacilli in sputum.
abstract: OBJECTIVE
  To determine if medical practitioners with congenital colour vision deficiencies (CCVD) are less able to identify and delineate the extent of coloured abnormal signs than those with normal colour vision.
  
  
  METHODS
  Twenty-two medical practitioners with CCVD and 17 with normal colour vision, matched for age and gender, were shown 10 photographs. They were asked to identify and outline the extent of the clinical sign in eight that were of vomit or stool (six of these showing fresh blood), one of a skin rash and for one to mark the position of bacilli in sputum stained by the Ziehl-Neelsen method.
  
  
  RESULTS
  There were statistically significant differences between the CCVD practitioners and those with normal colour vision in their ability to outline abnormalities in five of the six photographs that showed fresh blood, in the photograph of a rash and in marking the position of bacilli in the photograph of a stained slide.
  
  
  CONCLUSIONS
  Medical practitioners with CCVD are handicapped in their evaluation of the presence and extent of coloured clinical signs. Medical schools should ensure that students with CCVD are aware of their deficiency and know its severity, so they can take special care in clinical practice.
authors.affiliation: Department of Primary Care, Peninsula Medical School, Exeter, UK.
authors.forename: John L
authors.initials: JL
authors.lastname: Campbell
authors.forename: Lewis
authors.initials: L
authors.lastname: Griffin
authors.forename: J Anthony B
authors.initials: JA
authors.lastname: Spalding
authors.forename: Fraz A
authors.initials: FA
authors.lastname: Mir
mesh_terms: D001407:Bacillus / Q000302:isolation & purification; D001769:Blood / Q000378:metabolism; D002983:Clinical Competence; D003116:Color; D003117:Color Vision Defects / Q000151:congenital / Q000503:physiopathology*; D003872:Dermatitis / Q000473:pathology; D006233:Persons with Disabilities; D005243:Feces / Q000737:chemistry; D006396:Hematemesis / Q000473:pathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010820:Physicians; D012867:Skin / Q000473:pathology; D013183:Sputum / Q000382:microbiology; D019987:Persons with Visual Disabilities