Posterior staphylomas will present as a crescentic shadow located 2-3 disk diameters from the optic nerve. Severe staphylomas may also present in patients as an enlarged and protruding eye. Presenting symptoms of staphyomas include significantly worsening of vision in previously myopic patients. Staphylomas often present in highly myopic patients. Secondary etiologies such as trauma or infection can disrupt the structure of the sclera, placing the injured region at risk for subsequent scleral thinning, to eventual development of staphyloma. Myopic eyes have increased elasticity due to its longer axial length, which causes it to expand and gradually thin to form these outpouchings. The etiology of the formation of staphylomas are unclear, however there is postulation that local choroidal factors and a decreased resistance of the sclera leading to a protruding Bruch’s membrane can result in staphylomas. Congenital disease associations include any condition causing defects in Bruch’s membrane, such as retinitis pigmentosa, Alport’s syndrome, pseudoxanthoma elasticum, and tilted-disc syndrome. In the non-myopic eye, staphylomas can be seen as a response to trauma or infection, and rarely, surgery. Staphylomas are associated with other macular complications related to myopia, such as choroidal neovascularization, retinoschisis, and glaucomatous optic neuropathy. Though, it is important to note that not all patients with myopia develop a staphyloma. The definition of pathologic myopia has been updated to include the presence of a posterior staphyloma. Up to 50% of patients with pathologic myopia are reported to have a staphyloma. Patients with pathologic myopia are at increased risk for posterior staphylomas. Up to 9% of Asian and 2% of White population in the United States have pathologic myopia, which increases their likelihood of having concurrent posterior staphyloma. The progression of posterior staphyloma may not stop at any specific age, unlike the moderate myopia cases which usually stabilize at around 18-21 years of age.
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