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
Muscae volitantes are seen in 
Select and explain. 
A. Vitreous detachment, B. Vitreous hemorrhage, C. Eale’s disease, D. Remains of primitive hyaloid vasculature
D: Remains of primitive hyaloid vasculature
Answer: D: Remains of primitive hyaloid vasculature 
Explanation: These are physiological opacities and represent the residues of primitive hyaloid vasculature.
Patient perceives them as fine dots and filaments, which often drift in and out of the visual field, against a bright background (e.g., clear blue sky).