Colour blindness: Why is it more prominent in men?

Colour blindness or colour deficiency is a condition in which a person is not able to distinguish or differentiate between certain colour usually red, green, or blue. Speaking to HT Lifestyle, Dr Neetu Sharma, Consultant, Opthalmologist, Fortis Hospital, Noida said, “Red – green colour deficiency is an x- linked recessive trait, which means that the green responsible for the colour vision defect is transmitted from the carrier mother to her son on the x- chromosome that he inherits from her - men have one x and one y chromosomes in their genetic composition.”

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Why is colour blindness more prominent in men than women?

In an interview with HT Lifestyle, Dr O P Anand, Director and Senior Consultant, Opthamology, Accord, Super Speciality Hospital, Faridabad said, “Approximately 8% men population is colour blind and 0.5% women population is colour blind. Important crux of colour blindness is hereditary disorder.”

This happens because women are spared from Red-green colour defect which is the predominant form of colour deficiency. Women have two z chromosomes and even if she inherits one mutated x chromosome, the second normal x chromosome helps her to have normal colour vision. Hence majority of colour deficiencies are in men and are congenital.

Dr OP Anand added, “A man having X-chromosome having defective gene will present with defective colour vision despite its recessive nature, but a woman will not suffer with defective colour perception due to its recessive nature but one will be a potential carrier of defective colour vision.”

However, acquired colour blindness can affect men and women equally. The initial symptoms include sudden colour vision problems. This can happen due to multiple reasons – some of them include usage of drugs like sildenafil, Ethambutol digoxin and some antimalarial and also by optic nerve diseases, diabetes, chronic alcoholic and certain retinal diseases. In such cases, Dr Neetu Sharma suggested an urgent check-up to denote any serious underlying causes.