**Core Concept**
The change in near vision involves a complex interplay between the ciliary muscles, the zonular fibers, and the lens of the eye. In near vision, the ciliary muscles contract, leading to a decrease in tension in the zonular fibers, which in turn causes the lens to become more spherical. This change in lens shape increases the refractive power of the lens, allowing for near vision.

**Why the Correct Answer is Right**
In near vision, the depth of focus increases due to the increased refractive power of the lens. This is because the more spherical lens shape allows for a greater range of accommodation, enabling the eye to focus on objects at different distances. The increased depth of focus is a result of the lens's ability to change shape and refractive power in response to the contraction of the ciliary muscles. This is known as accommodation.

**Why Each Wrong Option is Incorrect**
**Option A:** The power of the lens actually increases in near vision, not decreases. This is due to the contraction of the ciliary muscles, which reduces the tension in the zonular fibers, allowing the lens to become more spherical and increase its refractive power.
**Option C:** The lateral recti muscles are responsible for eye movements, such as convergence and divergence, but they are not directly involved in the change in near vision. The change in near vision is primarily controlled by the ciliary muscles and the zonular fibers.
**Option D:** Zonular tension actually decreases in near vision, not increases. The contraction of the ciliary muscles reduces the tension in the zonular fibers, allowing the lens to become more spherical and increase its refractive power.

**Clinical Pearl / High-Yield Fact**
A key point to remember is that the ciliary muscles are responsible for the change in near vision, and the contraction of these muscles reduces the tension in the zonular fibers, allowing the lens to become more spherical and increase its refractive power. This is a critical concept for understanding accommodation and the changes that occur in the eye during near vision.

**✓ Correct Answer: B. Depth of focus increases**