Commonest cause of posterior staphyloma:
**Core Concept**
Posterior staphyloma refers to a localized thinning and bulging of the posterior sclera, often associated with pathologies that lead to weakening of the scleral tissue. This condition can result from various etiologies, including high myopia, ocular trauma, and uveal effusion.
**Why the Correct Answer is Right**
The correct answer is **B. High myopia**. High myopia is a significant risk factor for the development of posterior staphyloma. This is because the prolonged axial elongation of the eyeball in high myopia can lead to thinning and stretching of the sclera, ultimately resulting in posterior staphyloma. The scleral tissue, which normally provides structural support to the eyeball, becomes compromised due to the increased intraocular pressure and the mechanical stress induced by the elongated globe.
**Why Each Wrong Option is Incorrect**
**Option A:** Uveal effusion syndrome is a condition characterized by the accumulation of fluid in the uveal tract, which can lead to secondary ocular complications, including cataract and glaucoma. However, it is not a primary cause of posterior staphyloma.
**Option C:** Ocular trauma can indeed lead to posterior staphyloma, but it is not the most common cause. Traumatic staphyloma is a specific entity that occurs following a direct injury to the eyeball, resulting in localized scleral thinning.
**Clinical Pearl / High-Yield Fact**
In patients with high myopia, posterior staphyloma can increase the risk of retinal detachment and other ocular complications. Early detection and management of posterior staphyloma are crucial to prevent these secondary complications.
**Correct Answer: B. High myopia**