This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous, Subject name: Ophthalmology
All of the following causes coloured halos except 
Select and explain. 
A. Corneal edema, B. Retinal degeneration, C. Foreign body, D. Steroids
B: Retinal degeneration
Answer: B: Retinal degeneration 
Explanation: Halos can sometimes be a normal response to bright lights. Halos can also be caused by wearing eyeglasses or corrective lenses (contact lenses), or they can be a side effect of cataract or LASIK surgery. ... Thehalos are a result in diffraction of light entering your eye