Question

Differentiate between the Following:

Night blindness and Colour blindness

Answer 1

Basis of Difference	Night Blindness	Colour Blindness
Nature of Defect	It is a nutritional vision disorder in which a person experiences severe difficulty seeing in dim light or at night.	It is a genetic disorder in which a person cannot discriminate between certain colours, particularly red and green.
Underlying Cause	It is caused by the non-formation of the rhodopsin (visual purple) pigment due to dietary deficiency of Vitamin A.	It is caused by an inherited genetic defect leading to the malformation or absence of specific cone photopigments.
Photoreceptor Cells Affected	It specifically impairs the functioning of rod cells, which mediate twilight (scotopic) vision.	It specifically impairs the functioning of cone cells, which mediate daylight (photopic) and colour vision.
Curability and Management	It is curable and can be corrected by adopting a proper lifestyle and consuming a diet rich in Vitamin A.	It is an incurable congenital condition that cannot be cured through diet, medicine, or optical lenses.
Pattern of Occurrence	It is an acquired deficiency disorder that affects individuals of either sex depending on their nutrition.	It is an inherited sex-linked disorder that predominantly affects males.