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
Increased LDH in Aqueous Humor suggests a diagnosis of: 
Select and explain. 
A. Galactosemia, B. Retinoblastoma, C. Glaucoma, D. Gyrate atrophy
B: Retinoblastoma
Answer: B: Retinoblastoma 
Explanation: The activity of Lactate Dehydrogenase (LDH) is greater in aqueous humour than in serum in patients with retinoblastoma. The aqueous /plasma ratio of LDH is greater than 1.50 in pateints with retinoblastoma and less than 0.6 in other ocular condition. The reason for this increase may be attributed to the necrotic nature of retinoblastoma, which allows more cytosol enzymes (LDH) to reach aqueous. Ref: Textbook of Ophthalmology By Sunita Agarwal, Athiya Agarwal, Vol 1, 2002, Page 65; Clinical Ophthalmology: A Systemic Approach By Jack J Kansk, Brad Bowling, 7th Edition, Page 2005