**Core Concept**
Against-the-rule astigmatism is a type of astigmatism where the steepening of the cornea is more horizontal, resulting in nearsightedness in the vertical meridian and farsightedness in the horizontal meridian. This condition is less common than with-the-rule astigmatism and often requires specific corrective lenses.

**Why the Correct Answer is Right**
In against-the-rule astigmatism, the horizontal meridian of the cornea is more curved than the vertical meridian, causing light to be focused in front of the retina when looking at distant objects. This leads to nearsightedness in the vertical meridian. The irregular curvature of the cornea disrupts the normal refractive process, resulting in astigmatism.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is not provided, so we'll skip it.
**Option B:** This option may be a distractor, but it doesn't directly relate to against-the-rule astigmatism.
**Option C:** This option might be a common symptom of astigmatism, but it's not specific to against-the-rule astigmatism.

**Clinical Pearl / High-Yield Fact**
Remember that against-the-rule astigmatism is often more challenging to diagnose than with-the-rule astigmatism, as the symptoms may be subtle and require a thorough eye examination.

**Correct Answer:** B. Against-the-rule astigmatism is characterized by a more curved horizontal meridian, resulting in nearsightedness in the vertical meridian.