This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Ophthalmology
Acquired colour blindness is due to 
Select and explain. 
A. Increased sclerosis of the crystalline lens, B. Transient failure of retinal circulation, C. Occlusion of short posterior ciliary arteries, D. Non- Inflammatory edema of optic disc
A: Increased sclerosis of the crystalline lens
Answer: A: Increased sclerosis of the crystalline lens 
Explanation: May occurs in old age due to increased sclerosis of crystalline lens.
May follow damage to macula or optic nerve.