Colour-blindness- some basic facts


Colour-blindness- some basic facts

Muhammad Shoaib Akhtar
Gulab Devi Postgraduate Medical Institute Lahore.

Colour-blinds are not blind to colours but they are deficient to discriminate colours. Colour-blindness is a hereditary disease. It affects the vision of three primary colours, red, green and blue. It is an X-linked disease and most commonly present in males. Worldwide prevalence of colour-blindness is 7%. In Caucasians, prevalence is higher than others i.e., 8%. In Pakistan, prevalence is not exactly known but some studies showed its prevalence 2.24-2.75%.

Colour blindness is generally of  three types  i.e., red-green colour-blindness, green-red colour-blindness and blue-yellow colour-blindness. Red-green colour-blindness is most common. Inheritance pattern of colour-blindness is from maternal grandfather to maternal grandson. Most often, mother of the affected individual is career. Females are rarely affected due to its X-linkage. The only condition, in which, females affected is career mother and affected father. But it may also be acquired due to trauma, side effect of some drug and/or through some neurologic disease.

Best ever diagnosis of colour-blindness is using Ishihara Plates. Ishihara Plates were designed in 1917 and still are gold standard to diagnose this condition. These plates are portable, economic and easy to use. For further diagnosis, anomaloscope is used but it can only be used in healthcare settings.

Treatment of colour-blindness is still a problem. Presently, there is no treatment for colour-blindness except counseling the patient. Patient should be counselled for his right profession because colour-blinds cannot join military services, aviation services and cannot drive properly in ideal conditions. Moreover, in medical profession colour-blindness is also a barrier to learning and to perform. It may affect professionalism in gross examination, during microscopy and physical examination of patient. Besides counseling, there is great work of international scientist to develop gene therapy for it. Gene therapy of colour-blindness is found successful in animal models. But it is not sure when it will get available for humans.

In Pakistan and other Asian countries, major cause of colour-blindness is inbreeding and consanguinity (cuisine marriages). It should be avoided after screening of in laws. It’s the only way for its prevention.  E mail: This email address is being protected from spambots. You need JavaScript enabled to view it.