This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Neuro Ophthalmology, Subject name: Ophthalmology
Not a common cause of night blindness: 
Select and explain. 
A. Cataract, B. RP, C. Oguchi disease, D. Pathological myopia
A: Cataract
Answer: A: Cataract 
Explanation: Cataract is not a common cause of night blindness. Other causes are more recognized causes. Causes of Night Blindness Vitamin A deficiency (first symptom is red-green differentiation anomaly) Pathological myopia Tapetoretinal degenerations{eg. Retinitis pigmentosa(RP)} Familial congenital night blindness Oguchi's disease