Table 2

Comparison of men who in 1991, aged 33 years, worked in “target” occupations, according to colour vision status

Occupation	Normal colour vision		Colour vision defect		Difference in proportion
	n = 3665		n = 267		% normal – % CVD
	n	%	n	%	% difference	95% CI	p value
*Preclusion on basis of safety.
†Preclusion on basis of quality of product.
Armed forces*	23	0.6	2	0.8	−0.1	−1.2 to 0.9	0.82
Transport operation*	6	0.2	0	0	0.2	0.03 to 0.3	0.01
Aircraft and ships’ officers*	11	0.3	0	0	0.3	0.1 to 0.5	0.001
Police, fire-fighting, and protective services*	118	3.2	6	2.3	1.0	−0.9 to 2.8	0.31
Electrical and electronic engineering*	15	0.4	0	0	0.4	0.2 to 0.6	<0.001
Electrical fitting and wiring*	11	0.3	1	0.4	−0.07	−0.8 to 0.7	0.85
Electrical installation and maintenance*	74	2.0	4	1.5	0.5	−1.0 to 2.0	0.50
Medicine, pharmacy, health diagnosing, and treatment*†	25	0.7	4	1.5	−0.8	−2.3 to 0.7	0.28
Laboratory and engineering technology*†	47	1.3	4	1.5	−0.2	−1.7 to 1.3	0.78
Painting and related coating†	39	1.1	3	1.1	−0.06	−1.4 to 1.2	0.93
Fibre and textile processing†	18	0.5	0	0	0.5	0.3 to 0.7	<0.001
Wood processing and paper making†	1	0.03	0	0	0.03	−0.03 to 0.08	0.32
Horticulture†	23	0.6	2	0.8	−0.1	−1.2 to 0.9	0.82
Biological, chemical, and geological science†	18	0.5	2	0.8	−0.3	−1.3 to 0.8	0.63
Printing, paper, and photographic processing†	15	0.4	1	0.4	0.03	−0.7 to 0.8	0.93
Art, sculpture, photography, and industrial design†	21	0.6	0	0	0.6	0.3 to 0.8	<0.001
Total in “target” occupations	465	12.7	29	10.9	1.8	−2.1 to 5.7	0.36