**Question:** Posterior staphyloma, most common cause –

A. Age-related macular degeneration
B. Primary open-angle glaucoma
C. Dry eye syndrome
D. Corneal ectasia

**Core Concept:** Posterior staphyloma is a condition characterized by the bulging of the posterior part of the sclera (the white part of the eye) due to the weakening of the collagen fibers that hold the sclera in place. This weakening is usually associated with aging, leading to the deformation of the sclera and the formation of posterior staphyloma.

**Why the Correct Answer is Right:** The correct answer is B. Primary open-angle glaucoma, as it is the most common cause of posterior staphyloma. In glaucoma, there is an elevation of intraocular pressure due to the blockage of the trabecular meshwork, which is responsible for regulating the outflow of aqueous humor. This elevated pressure can lead to damage to the optic nerve head and retinal ganglion cells, resulting in the development of posterior staphyloma as a compensatory mechanism to protect the delicate structures in the eye.

**Why Each Wrong Option is Incorrect:**

A. Age-related macular degeneration (AMD) is a disease affecting the macula, the central part of the retina responsible for sharp vision. Posterior staphyloma is not a direct consequence of AMD, as the condition primarily affects the macula, not the sclera.

C. Dry eye syndrome is a condition characterized by a deficiency of tears that result in discomfort, visual disturbances, and dryness of the eye surface. Posterior staphyloma is not a direct consequence of dry eye syndrome, as the latter primarily affects the cornea and conjunctiva, not the sclera.

D. Corneal ectasia, also known as keratoconus, is a condition characterized by the progressive thinning and bulging of the cornea, which can lead to visual disturbances and myopia progression. Posterior staphyloma is not a direct consequence of corneal ectasia, as the latter primarily affects the cornea, not the sclera.

**Clinical Pearl:** Posterior staphyloma may be an incidental finding during a routine eye examination and is often asymptomatic. However, it can be an indicator of underlying eye diseases like glaucoma, cataracts, or retinal disorders. Therefore, it is essential for healthcare professionals to be aware of the potential causes and clinical implications of posterior staphyloma for an accurate diagnosis and proper management of patients exhibiting this condition.