**Core Concept**
The accommodation reflex is a complex process involving the coordinated effort of multiple muscles to focus light on the retina, achieved through changes in the shape of the eye. This process involves the contraction and relaxation of various extraocular muscles and the ciliary muscles.

**Why the Correct Answer is Right**
The correct answer involves identifying the muscle that is not involved in the accommodation reflex. The accommodation reflex primarily involves the contraction of the ciliary muscles, which causes the lens to become more rounded, and the contraction of the rectus muscles, particularly the medial rectus, to converge the eyeballs. The superior oblique muscle is not directly involved in the accommodation reflex, as its primary function is to rotate the eyeball and move it downward.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the ciliary muscles are directly involved in the accommodation reflex by altering the shape of the lens.
**Option C:** This option is incorrect because the rectus muscles, including the medial rectus, are involved in the accommodation reflex by converging the eyeballs.

**Clinical Pearl / High-Yield Fact**
The accommodation reflex is an essential process for maintaining clear vision, particularly in low-light conditions. It is mediated by the parasympathetic nervous system, which stimulates the contraction of the ciliary muscles and the rectus muscles.

**Correct Answer: D. Superior oblique muscle is not involved in accommodation reflex.**