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
All of the following are true for colloid bodies (drusens) except: 
Select and explain. 
A. Are hyaline excrescences of Bruch's membrane, B. Are secreted by pigment epithelial cells, C. Are usually associated with marked loss of vision, D. Are a percursor of disciform maci degeneration in some eyes
C: Are usually associated with marked loss of vision
Answer: C: Are usually associated with marked loss of vision 
Explanation: Ans. Are usually associated with marked loss of vision