**Core Concept**
The management of corneal opacity depends on its location, size, and depth. In the context of nebular corneal opacity, which is a superficial and faint corneal scar, treatment options are aimed at improving visual acuity and corneal clarity. The treatment choice is crucial in preventing further complications and ensuring optimal outcomes.

**Why the Correct Answer is Right**
Nebular corneal opacity, characterized by a 0.1 to 0.2 mm corneal thickness, is often treated with superficial keratectomy or phototherapeutic keratectomy (PTK). PTK involves the use of an excimer laser to ablate the affected corneal tissue, thereby removing the scar and improving corneal clarity. This treatment is particularly effective for superficial corneal scars and has a high success rate in patients with mild to moderate corneal opacity.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because it does not specify a recognized treatment for nebular corneal opacity. While various treatments may be used for corneal scars, this option lacks the precision and accuracy required for a correct answer.
* **Option B:** This option is incorrect because it does not align with the standard treatment protocols for nebular corneal opacity. While corneal transplantation may be considered in severe cases of corneal scarring, it is not typically used for superficial scars with minimal impact on visual acuity.

**Clinical Pearl / High-Yield Fact**
When managing corneal scars, it is essential to assess the depth and location of the scar, as well as the patient's visual acuity and overall eye health. A thorough examination and evaluation of the cornea can help determine the most appropriate treatment approach and prevent unnecessary complications.

**Correct Answer: C. Phototherapeutic keratectomy (PTK)**