**Core Concept**
Presbyopia is a common age-related condition characterized by decreased near vision, typically occurring after the age of 40. It is caused by a reduction in the eye's ability to focus on close objects, resulting from changes in the lens and the surrounding ciliary muscles.

**Why the Correct Answer is Right**
The correct answer is related to the physiology of accommodation, which is the process by which the eye changes optical power to maintain a clear image or focus on an object as its distance varies. The lens's ability to change shape and focus light on the retina is essential for accommodation. However, with age, the lens becomes less flexible, and the ciliary muscles, which control the lens's shape, also undergo changes. Specifically, the ciliary muscles become less effective in changing the lens's shape, and the lens's ability to move anteriorly (forward) is reduced. This reduction in anterior movement of the lens is a key factor in the development of presbyopia.

**Why Each Wrong Option is Incorrect**
**Option A:** Loss of elasticity of the capsule is a contributing factor to presbyopia, as the lens capsule becomes less flexible with age, making it more difficult for the lens to change shape.

**Option B:** Sclerosis of lens fibres is a change associated with presbyopia, as the lens fibres become more rigid and less able to change shape with age.

**Option D:** Reduced contraction of the ciliary muscle is also a factor in presbyopia, as the ciliary muscles become less effective in changing the lens's shape with age.

**Clinical Pearl / High-Yield Fact**
A key point to remember is that presbyopia is not a disease, but rather a natural age-related change in the eye's ability to focus on close objects. It is essential to distinguish presbyopia from other eye conditions that may cause similar symptoms.

✓ Correct Answer: C. Reduced anterior movement of the lens