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
Regarding amblyopia which of following is true: 
Select and explain. 
A. Reversible loss of vision, B. Associated with squint, C. Defect in refractive error, D. All
D: All
Answer: D: All 
Explanation: A. i.e. Reversible loss of vision; B. i.e Associated with squint; C. Defect in refractory error