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: Unknown
Central macular fixation developed at : 
Select and explain. 
A. 3 weeks, B. 3 months, C. 6 weeks, D. 6 months
D: 6 months
Answer: D: 6 months 
Explanation: The critical period of developed of fixation reflex is 5-6 months of age.
This is the reason why unilateral cataracts in children should be operated early. Remember –
Binocular vision develops at 5-6 years.