This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Ophthalmology
Retinoblastoma is bilateral in 
Select and explain. 
A. 100 % of cases, B. 1 % of cases, C. 50 % of cases, D. 30 % of cases
D: 30 % of cases
Answer: D: 30 % of cases 
Explanation: Retinoblastoma: It is a malignant glioma of the retina, usually unilateral, that occurs in young children and usually is hereditary. In about 30 % of patients retinoblastoma is bilateral. The initial diagnostic finding is usually a yellow or white light reflex seen at the pupil (cat's eye reflex).