Colour blindness distribution in the male population of Rome

A total of 3,285 young males selected at random from the school population of Rome have been administered the Ishihara plates for colour blindness. Those who failed to read all plates correctly were further administered Farnsworth's Panel D-15 and the diagnoses of colour blindness were made by an ophthalmologist and cross checked. A total of 201 subjects were found to be colour-blind, allowing a gene frequency estimate of 0.061 +/- 0.004. This is the first reliable estimate for the Italian population and appears to be lower than for other Caucasoid populations. The gene frequency of colour blindness is known to increase from 0.02-0.04 in 'primitive' populations to 0.07-0.09 in Caucasoid populations, possibly as a result of a selection relaxation.