Pathophysiology of Angioid Streaks
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In 1889, Doyne first described angioid streaks in a patient with retinal hemorrhages secondary to trauma. Angioid streaks, also known as Knapp striae, are irregular jagged dehiscences in the mineralized, degenerated, brittle Bruch membrane that typically form alongside force lines exerted by intrinsic and extrinsic ocular muscles that radiate in a centrifugal pattern emanating from the optic disc. Knapp named them angioid streaks because of their resemblance to blood vessels
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@ayra Controversy about the pathophysiology of angioid streaks exists. In some diseases, including pseudoxanthoma elasticum (PXE) and Paget disease, the Bruch membrane may become calcified and brittle with subsequent development of cracks. However, cytoimmunochemistry and x-ray analysis had shown that the earliest abnormality in PXE was abnormal accumulation and metabolism of polyanions (ie, glycosaminoglycans, glycoproteins) within the Bruch membrane. The lines of force within the eye resulting from the pull of intrinsic and extrinsic ocular muscles on the relatively fixed site of the optic nerve have been studied. Those lines of forces had the same configuration as the peripapillary interlacement and radial extensions of angioid streaks. Such forces acting on the Bruch membrane undoubtedly account for the configuration of the breaks. However, in sickle cell disease, Bruch membrane calcification is not a common part of the pathology.