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
A patient with cataract exhibits polychromatic lustre of reds, greens and blues. He is having the following type of cataract: 
Select and explain. 
A. Complicated cataract, B. Diabetes mellitus, C. Post-radiation cataract, D. Congenital cataract
A: Complicated cataract
Answer: A: Complicated cataract 
Explanation: Complicated cataract refers to opacification of the lens secondary to some other intraocular disease. Typically the complicated cataract stas as posterior coical cataract. Lens changes appear typically in front of the posterior capsule. The opacity is irregular and variable in density. In the beam of slit lamp the opacities have an appearance like 'bread crumb'. A very characteristic sign is the appearance of iridescent coloured paicles the so-called 'polychromatic lustre' of reds, greens, and blues. A diffuse yellow-haze is seen in the adjoining coex. Ref: Ophthalmology by A K Khurana, 4th edition, Page 181-182.