This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Lens, Subject name: Ophthalmology
A 55 year old patient complains of decreased distance vision. However, now he does not require his near glasses for near work. The most likely cause is- 
Select and explain. 
A. Posterior subcapsular cataract, B. Zonular cataract, C. Nuclear sclerosis, D. Anterior subcapsular cataract
C: Nuclear sclerosis
Answer: C: Nuclear sclerosis 
Explanation: This is a typical example of second-sight. Ref: Ophthalmology by Ducker 2nd/e p.412. (Ref: Ophthalmology by Ducker 2nd/e p.412) This is a typical example of second-sight. When a neclear cataract develops, it can bring about a temporary improvement in near vision, called 'second sight'.