Okay, let's tackle this question about Marfan syndrome and its ocular manifestations. First, I need to recall what Marfan syndrome is. It's a genetic disorder affecting connective tissue, right? So, the core concept here is the connective tissue abnormalities leading to various systemic issues, including the eyes.

The question is asking for the prominent ocular manifestation. I remember that Marfan syndrome can cause lens dislocation. Specifically, it's called ectopia lentis. The lens is displaced because the zonules that hold it in place are weakened due to the connective tissue defect. That's a key point. So the correct answer should be ectopia lentis.

Now, looking at the options, even though they aren't listed here, typical distractors might include other ocular issues. Let's think about common wrong answers. For example, cataracts or glaucoma might be considered, but those are more associated with other conditions. Cataracts can occur in diabetes, and glaucoma is a separate issue. Another possible wrong answer could be retinal detachment, which can happen in Marfan but isn't as classic as ectopia lentis. Also, myopia is more common, but again, ectopia lentis is the hallmark.

The clinical pearl here is to remember that ectopia lentis is a diagnostic criterion for Marfan syndrome. It's often the first sign that leads to the diagnosis. The student should note that the lens is displaced superiorly and temporally in most cases, which is a key distinguishing feature.

Putting it all together, the correct answer is ectopia lentis. The explanation should highlight the defective zonules leading to lens dislocation. The wrong options should be addressed with why they don't fit, like other conditions causing similar symptoms but different underlying causes. The clinical pearl reinforces the importance of this finding in diagnosing Marfan syndrome.

**Core Concept**
Marfan syndrome is an autosomal dominant connective tissue disorder caused by mutations in the *FBN1* gene. It leads to structural weaknesses in tissues like the eye, cardiovascular system, and skeleton. A hallmark ocular manifestation is lens dislocation due to defective zonular fibers.

**Why the Correct Answer is Right**
Ectopia lentis (lens dislocation) is the classic ocular finding in Marfan syndrome. The defective fibrillin-1 protein weakens the zonular fibers that anchor the lens. This results in superior-temporal or superior-nasal lens displacement, often bilateral. The dislocation may cause astigmatism, visual distortion, or secondary glaucoma. Early detection is critical to prevent complications.

**Why Each Wrong Option is Incorrect**
**Option A:** Cataracts are not specific to Marfan syndrome and are more commonly age- or diabetes-related.
**Option B:** Retinal detachment occurs in Marfan syndrome but is less common than ectopia lentis.
**Option C:** Myopia may be present but is not pathognomonic for Marfan syndrome.
**Option D:** Glaucoma is a potential complication of ectopia lentis, not a primary manifestation.

**Clinical Pearl / High-Yield Fact**
Ectopia lentis is a major diagnostic criterion for Marfan syndrome per revised Ghent criteria. Always check for lens position in patients with tall stature, arachnodactyly, or family history of connective tissue

✓ Correct Answer: C. Ectopia lentis