Angioid streaks
Angioid streaks, also called Knapp streaks or Knapp striae, are small breaks in Bruch's membrane, an elastic tissue containing membrane of the retina that may become calcified and crack. Up to 50% of angioid streak cases are idiopathic. It may occur secondary to blunt trauma, or it may be associated with many systemic diseases. The condition is usually asymptomatic, but decrease in vision may occur due to choroidal neovascularization.
Presentation
Angioid streaks are often associated with pseudoxanthoma elasticum, but have been found to occur in conjunction with other disorders, including Paget's disease, sickle cell disease and Ehlers–Danlos syndrome. These streaks can have a negative impact on vision due to choroidal neovascularization or choroidal rupture. Also, vision can be impaired if the streaks progress to the fovea and damage the retinal pigment epithelium.Diagnosis
The diagnosis is mainly clinical, however fundus fluorescein angiography shows that the streaks appear hyperfluorescent in the early phase. Indocyanine green angiography can also be used for diagnosing angioid streaks and their associated ocular pathologies.Retinal fundus examination may reveal grey or dark red spoke like lesions around optic disk and radiating outward from peripapillary area. Peau d'orange, also known as leopard skin pattern may be seen in association with pseudoxanthoma elasticum. Optic disc drusen may also seen.