ANGIOID STREAKS

Angioid streaks refer to a pattern of radiating folds or cracks originating from the optic nerve of patients below the retina. The presence of angioid streaks cannot be ignored because it has the potential to lead to retinal complications which may cause long term vision loss. In addition, angioid streaks may signify the presence of another disease within the patient’s body.

CAUSE

Angioid streaks are small cracks in the Bruch’s membrane which underlies the retina and separates the retina from the choroid, a tissue layer found beneath the retina. Bruch’s membrane physically separates the retina and choroid and ensures that no large molecules cross from the choroid to the retina. Thus, angioid streaks or breaks in the Bruch’s membrane may lead to complications in the retina. Eventually, angioid streaks can cause retinal distortion, the formation of scotomas, or blind spots, and the progressive loss of central vision.

ASSOCIATION WITH SYSTEMATIC DISEASE

The presence of angioid streaks is associated with many diseases, including pseudoxanthoma elasticum (PXE), Ehlers-Danlos syndrome, Marfan’s syndrome, sickle cell disease, and Paget’s disease to name a few. It is therefore important that patients who have angioid streaks tell their general practitioners in order to further investigate their systemic condition.

OCULAR MANIFESTATION

With respect to the ocular manifestation of this disease, it is limited to the posterior segment where the cracks extending from the optic nerve can lead to both direct and indirect problems. For example, the cracks themselves can lead to visual distortion if they extend through the macular region.

Further complications associated with angioid streaks include the development of abnormal choroidal neovascular membranes. In short, this condition leads to the formation of abnormal blood vessels which grow from the choroid and through the cracks in Bruch’s membrane into the retina. The fragility of these blood vessels makes them susceptible to bleeding in the retina while their swollen shapes tear and cover the retina. As a result, there can be severe visual distortion and loss and even fibrotic membrane development or excessive fibrotic tissue growth in the central macular region from the optic nerve.

A key symptom of angioid streaks in association with fibrotic tissue growth from the optic membrane is the formation of dark snake like streaks extending from the optic nerve to the retina. This occurs because the penetration of the fibrotic tissues through the choroid and then angioid streaks allows them to put pressure on retinal blood vessels causing them to become darker in color. The specific identification of this symptom may be difficult due to racial pigmentation and thus your physician may use fluorescein angiography along with autofluorescence to identify and monitor the progression of these streaks. The development of abnormal choroidal neovascular membranes will also be checked using the aforementioned image technologies.