HEREDITARY CHOROIDAL DYSTROPHIES

1. Choroideremia

2. Gyrate atrophy

3. Central areolar choroidal dystrophy

4. Diffuse choroidal atrophy

ChoroideremiaInheritance - X-linked recessive

• Circumscribed atrophy of RPE and choroid• Starting in periphery

• Gradual central spread• Fovea spared until late

Presents - first decade with nyctalopiaPrognosis - good VA until lateERG - reduced

Progression

FA in choroideremia

• Preservation of larger choroidal vessels• Hypofluorescence at fovea due to preservation of RPE• Surrounding irregular hyperfluorescence due to preservation of choriocapillaris and partial loss of RPE

• Normal retinal vasculature• Diffuse loss of choriocapillaris

Female carriers of choroideremia

Peripheral diffuse pigmentary granularity

Central patchy atrophy and mottling of RPE

Gyrate atrophy

• Mid-peripheral, circular patches of chorioretinal atrophy

• Enlargement and confluence

• Central and peripheral spread• Late retinal vascular attenuation

Inheritance - autosomal recessivePresents - first decade with axial myopia and nyctalopiaPrognosis - usually good VA until lateERG - severely reduced

Cause - deficiency of ornithine keto-acid aminotransferase

• Fovea spared until late

Progression

Central areolar choroidal dystrophy

• Bilateral, circumscribed, atrophic maculopathy• Prominent large choroidal vessels

Inheritance - dominantPresents - fifth decadePrognosis - poorERG - normal

Diffuse choroidal atrophy

• Diffuse atrophy of RPE and choriocapillaris• Prominent large choroidal vessels

Inheritance - dominantPresents - fourth to fifth decadesPrognosis - poorERG - reduced