Knapp Striae are also known as Angioid
Streaks and Knapp
Knapp Striae are a rare disorder of the eye / visual
They are a binocular condition, meaning that both eyes are usually affected.
Knapp Striae appear as reddish to dark-brown irregular
streaks extending radially outwards from the optic
disc beneath the retinal
vessels. These "streaks" are actually small irregular breaks
in the Bruch's
Membrane (an elastic tissue that can become calcified and crack).
Note that these would be seen on the retina, not as radial
lines in the iris
when observing the patient with the naked eye.
Problems that can result from Knapp Striae:
Recall from knowledge of the structure
of the eye, that the choroid
is the thin highly vascular (that is, containing many blood
vessels) layer of the eyeball located between the retina
and the sclera,
and that the Bruch's Membrane is the transparent innermost layer of the
The small breaks in the Bruch's Membrane known as Knapp Striae
can sometimes form the sites of new blood vessels that develop from the
choroid then leak, adversely affecting vision through the affected eye(s).
The apperance of Knapp Striae is one of the symptoms
associated with pseudoxanthoma elasticum, a hereditary disease
affecting elastic tissues. Approx. 50% of people with Knapp Striae
have pseudoxanthoma elasticum. The combination of Knapp
Striae and pseudoxanthoma elasticum is known as Grönblad-Strandberg
Syndrome, after Swedish Ophthalmologist, Ester E. Grönblad (1898-1942)
and Swedish Dermatologist, James V. Strandberg (1883-1942) and also has
several other names.
More about Ophthalmology: This section includes short definitions
of many diseases, disorders, and conditions of the eyes and visual system.
For definitions of other terms in this category, choose from the list
to the left (but note that this is not a complete/exhaustive list).
Other related pages include the diagram
of the eye, and definitions
of parts of the eye, a description
of the human retina, and definitions
of parts of the retina, and the section of short definitions
of clinical and surgical procedures re. eyes and human visual system.
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