Multimodal imaging in central areolar choroidal dystrophy.

Central areolar choroidal dystrophy (CACD) presents as a well-defined atrophy of the retinal pigment epithelium and the choriocapillaris resulting in progressive and profound visual loss.[1] The choroidal changes are secondary to the genetic abnormality expressed at the level of the photoreceptor layer.[2] Four stages of CACD have been described, with Stage 4 showing atrophy of the fovea, resulting in markedly decreased visual acuity.[1] We describe the importance of noninvasive multimodal imaging of CACD in this report.

A 41-year-old man presented with complaints of decreased vision in both eyes since childhood. Pedigree charting did not reveal any history of consanguinity. Systemic history was unremarkable. On examination, the corrected distance vision was 20/40 and 20/60 in the right and left eyes, respectively, and the near vision was 6/9 RS in both eyes. Fundus evaluation showed atrophic lesions at the macula with well-defined borders in both eyes. The patient underwent comprehensive imaging which included spectral-domain optical coherence tomography (SD-OCT) scans, fundus autofluorescence (FAF), multicolor imaging (MCI),[3] and optical coherence tomography angiography (OCTA).

The color fundus photographs [Figure 1a and 1b] and MCI images [Figure 1c and d] show a demarcated atrophic area at the macula. On FAF, this area appeared hypoautofluorescent [Figure 1e and f]. The SD-OCT [Figure 2a and b] scans through the macula showed partial loss of the outer nuclear layer with atrophy of the photoreceptor layer and the retinal pigment epithelium–Bruch's membrane complex with a patchy epiretinal membrane in both eyes. The MCI showed a prominent atrophy at the macula, better delineated on the infrared image when compared to green and blue reflectance, as the outer retinal layers are more involved. These findings corresponded to the atrophic changes in the outer retinal and choriocapillaris layers on the OCTA [Figure 2c and d]. The superficial and deep capillary plexus showed widening of the foveal avascular zone due to the atrophy but with no significant changes in the vasculature. The coarse pattern of the choriocapillaris was lost in the entire area of atrophy and seemed to be more severe at the foveal center compared to the perimeter of the lesion indicating a centrifugal progression. Larger (Haller's) vessels were visible at the foveal center and both the medium and large vessels were seen at the perimeter of the atrophy. These findings correlated well with the “differential atrophy” noted on MCI.

Figure 1

The color fundus photographs (a and b) and multicolor images (c and d) show a demarcated atrophic area at the macula. On fundus autofluorescence, this area appeared hypoautofluorescent in both eyes with no other abnormality (e and f)

Figure 2

The spectral-domain optical coherence tomography scans (a and b) through macula showed partial loss of the outer nuclear layer with atrophy of the photoreceptor layer and the retinal pigment epithelium–Bruch's membrane complex with a patchy epiretinal membrane in both eyes. Atrophic changes are noted in the outer retinal and choriocapillaris layers on the optical coherence tomography angiography (c and d)

An autosomal dominant disorder with complete or almost complete penetrance with a strong preponderance for a peripherin/RDS (Arg142Trp) mutation, late-stage CACD, can present with clinical characteristics that are similar to geographic atrophy secondary to age-related macular degeneration (AMD).[4] Drusen and variable degree of retinal pigment epithelium atrophy surrounding the geographic atrophy differentiate AMD from macular dystrophies such as CACD, especially in the absence of a positive family history.[5] While the atrophy is homogeneous in CACD, the atrophy in geographic atrophy is highly irregular and shows residual material on the Bruch's membrane.[5] Compared to FAF, MCI helps in better delineation of the vascular pattern and pigmentary changes in CACD. Hence, noninvasive multimodal imaging aids in reaching an accurate diagnosis with better understanding of the structural and morphological changes.

Informed consent

Informed consent for reporting this case was obtained from the patient.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given his consent for his images and other clinical information to be reported in the journal. The patient understands that name and initials will not be published and due efforts will be made to conceal identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.