Preparing medical students with congenital colour vision deficiency for safe practice

Colour vision of candidates is tested in many medical colleges in India at the time of admission to undergraduate courses; however, there are no guidelines, and therefore no counselling, on how students with congenital colour vision deficiency (CCVD) should negotiate the medical course, and how best they can practise safely after graduation. Problems in interpreting coloured signs may lead to misdiagnosis. This study aimed to explore difficulties during clinical work that requires colour discrimination, and to offer suggestions on safe practice based on the findings and a review of the literature.

We did a cross-sectional study after obtaining institutional ethical clearance and written informed consent. Thirty volunteer medical students with CCVD (≥3 errors on Ishihara chart) were matched with 30 volunteers from their own batch who made no errors. All participants interpreted colour-dependent clinical and laboratory photographs.

Students with CCVD made more errors (range 5-26; mean [SD] 13.17 [5.873] out of 75 items in 35 colour-dependent photographs) than colour-normal students (range 2-13; mean [SD] 5.53 [3.037], p<0.001). The nature of the errors suggested that medical students with CCVD could have problems in learning histology, pathology, haematology, microbiology, dermatology, paediatrics, medicine, biochemistry and during ophthalmoscopy.

Screening at the time of admission will make students aware of their CCVD status and, through conscious practice thereafter, they may understand their limitations. Faculty could guide and prepare such students for safe practice.