Central Areolar Choroidal Dystrophy

Central areolar choroidal dystrophy is a rare autosomal-dominantly inherited macular atrophy that can lead to a progressive and sometimes profound central vision loss. It is usually caused by a mutation in the PRPH2 gene. The age of onset depends on the underlying PRPH2 mutation and ranges from the third to the sixth decade.

Symptoms of CACD may include mild central vision loss, metamorphopsia, and central scotomas may be noted in advanced cases.
The hallmark feature of CACD is the bilateral symmetric presentation of well-defined atrophy of the outer retina, retinal pigment epithelium, and choriocapillaris in the macula.

In the early stage, there is a subtle parafoveal depigmentation at the macula. The depigmentation can enlarge into a round or oval area with OCT showing irregular reflectivity in the outer photoreceptor-RPE complex and fundus autofluorescence (FAF) showing speckled hyper and hypo-autofluorescence. In later stages, well-delineated atrophy develops with FAF showing profound hypo-autofluorescence and visual acuity often decrease to less than 6/60 (20/200) once the fovea is involved. The late stage of CACD can be easily confused with geographic atrophy in age-related macular degeneration. However, in contrast to AMD, atrophic lesion in CACD shows a sharply demarcated round-to-oval configuration and is generally without drusen. Choroidal neovascularisation is rare in CACD and may occur in patients with concurrent high myopia.

Additional differential diagnosis not currently covered in this resource include maternally inherited diabetes and deafness, North Carolina macular dystrophy and Sorsby fundus dystrophy.

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Boon CJ, Klevering BJ, Cremers FP et al. Central areolar choroidal dystrophy. Ophthalmology 2009; 116: 771-782, 782 e771.

Smailhodzic D, Fleckenstein M, Theelen T et al. Central areolar choroidal dystrophy (CACD) and age-related macular degeneration (AMD): differentiating characteristics in multimodal imaging. Invest Ophthalmol Vis Sci 2011; 52: 8908-8918.