This genetic condition has symptoms similar to classic retinitis pigmentosa, night vision difficulties often being the initial symptom, but degeneration of both the retina and the choroid (layer deep to the retina) occur.
Over time the visual field narrows and this progresses to tunnel vision and blindness. The rate of progression varies.
Choroideremia is genetically passed through families by an X-linked pattern of inheritance and most affects men.
Further detailed information on Choroideremia is available from: https://www.blindness.org/Choroideremia