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
In heterophoria prism is used: 
Select and explain. 
A. With apex towards the direction of phoria in glasses for treatment, B. With apex towards the direction of phoria for exercises only, C. For exercises mainly in hyperphoria, D. To detect grade III of binocular vision
A: With apex towards the direction of phoria in glasses for treatment
Answer: A: With apex towards the direction of phoria in glasses for treatment 
Explanation: Ans. With apex towards the direction of phoria in glasses for treatment