Introduction
Adult-onset foveomacular vitelliform dystrophy (AFVD) is one of the most prevalent forms of macular degeneration.1 AFVD has been included in the heterogeneous group of pattern dystrophy, in which the retinal pigment epithelium (RPE) is affected, along with butterfly-shaped pigment dystrophy, reticular dystrophy of the RPE, pseudo-Stargardt pattern dystrophy, and fundus pulverulentus.2 It shares phenotypical features with best vitelliform macular dystrophy, but onset is in adult age, typically between the fourth and sixth decades.1,3 It is a clinically heterogeneous and pleomorphic disease showing extreme variability in size, shape, and distribution of the subretinal deposition of yellowish material within the macula.4,5,6 However, AFVD is not a monogenic disorder, and some of the genes involved, such as PRPH2 or BEST1, are also involved in many other conditions such as Best disease, pattern dystrophies, or butterfly macular dystrophy.7 Therefore, diagnosis of AFVD remains based on clinical features and imaging of the macula.7
12.2 Conventional Multimodal Imaging
A variety of imaging tools and functional analyses have been used to diagnose and study AFVD. Using structural spectral-domain optical coherence tomography (SD-OCT), the natural course of the disease has been classified into four stages: vitelliform ( ▶ Fig. 12.1, ▶ Fig. 12.2, ▶ Fig. 12.3, ▶ Fig. 12.4, ▶ Fig. 12.5, ▶ Fig. 12.6, ▶ Fig. 12.7, ▶ Fig. 12.8), pseudohypopyon ( ▶ Fig. 12.9), vitelliruptive ( ▶ Fig. 12.10), and atrophic stage, during which patients typically have slow progressive vision loss. In the vitelliform stage, structural SD-OCT shows dome-shaped subretinal homogeneously hyper-reflective material between RPE/Bruch’s membrane and the ellipsoid zone (EZ) of the photoreceptors ( ▶ Fig. 12.1, ▶ Fig. 12.2, ▶ Fig. 12.3, ▶ Fig. 12.4, ▶ Fig. 12.5, ▶ Fig. 12.6, ▶ Fig. 12.7, ▶ Fig. 12.8). On infrared (IR) image, the vitelliform lesions appear as an inhomogeneous hyper-reflective zone ( ▶ Fig. 12.2 and ▶ Fig. 12.3); fundus autofluorescence (FAF) shows an increased signal that is not specific of AFVD ( ▶ Fig. 12.1, ▶ Fig. 12.2, ▶ Fig. 12.3, ▶ Fig. 12.4, ▶ Fig. 12.5, ▶ Fig. 12.6, ▶ Fig. 12.7, ▶ Fig. 12.8 and ▶ Fig. 12.10). The pseudohypopyon stage is characterized by the partial liquefaction of the lesion, corresponding, on structural SD-OCT, to a hyporeflective area in combination with a hyper-reflective homogeneous area containing the remaining vitelliform material ( ▶ Fig. 12.9). This hyporeflective material typically accumulates in the upper part of the lesion. Typically, the outer segment layers, overlying the liquefied area, present an irregular undersurface thickening representing deposits of nonphagocytized shed photoreceptor outer segment material. In the vitelliruptive stage, the lesion flattens, much of the fluid is reabsorbed, and atrophy of the outer retina and RPE is evident ( ▶ Fig. 12.10). In the atrophic stage, the vitelliform material is completely reabsorbed resulting in the atrophy of the photoreceptor outer and inner segments, and atrophy of the outer nuclear layer and RPE. However, subfoveal choroidal neovascularization (CNV) may occur in few cases ( ▶ Fig. 12.10). Such complication occurs at an estimated rate of 11.7% after 6 years’ follow-up.8 Unfortunately, accumulation of yellowish subretinal material makes the diagnosis of CNV difficult, due to its masking effect.
Fig. 12.1 Multicolor image, fundus autofluorescence (FAF), structural spectral-domain optical coherence tomography (SD-OCT), and OCT angiography (OCTA) of adult-onset foveomacular vitelliform dystrophy at the vitelliform stage. Multicolor image shows (a) central vitelliform material and FAF shows (b) central hyper-autofluorescence. (c) SD-OCT reveals the lesion as hyper-reflective material between retinal pigment epithelium/Bruch’s membrane and the ellipsoid zone of the photoreceptors. On OCTA, the subretinal material leads to displacement of blood vessels at both the (d) superficial and (e) deep capillary plexus of the retina, associated with apparent vascular rarefaction at the (f) choriocapillaris.
Fig. 12.2 Infrared (IR) reflectance, fundus autofluorescence (FAF), structural spectral-domain optical coherence tomography (SD-OCT), and OCT angiography (OCTA) of adult-onset foveomacular vitelliform dystrophy at the vitelliform stage. IR reflectance shows (a) mixed hyper-reflective/hyporeflective material and FAF shows (b) central hyper-autofluorescence/hypo-autofluorescence. SD-OCT (c) reveals the lesion as a hyper-reflective material between retinal pigment epithelium/Bruch’s membrane and the ellipsoid zone of the photoreceptors with a small hyporeflective area that corresponds to an early resorption of vitelliform material. On OCTA, the subretinal material leads to displacement of blood vessels at both the (d) superficial and (e) deep capillary plexus of the retina, associated with apparent vascular rarefaction at the (f) choriocapillaris.
Fig. 12.3 Infrared (IR) reflectance, fundus autofluorescence (FAF), structural spectral-domain optical coherence tomography (SD-OCT), and OCT angiography (OCTA) of adult-onset foveomacular vitelliform dystrophy at the vitelliform stage. IR reflectance shows (a) mixed hyper-reflective/hyporeflective material and FAF shows (b) central hyper-autofluorescence/hypo-autofluorescence. SD-OCT (c) reveals the lesion as a hyper-reflective material between retinal pigment epithelium/Bruch’s membrane and the ellipsoid zone of the photoreceptors with a small hyporeflective area that corresponds to an early resorption of vitelliform material. On OCTA, the subretinal material leads to displacement of blood vessels at both the (d) superficial and (e) deep capillary plexus of the retina, associated with apparent vascular rarefaction at the (f) choriocapillaris.
Fig. 12.4 Multicolor image, fundus autofluorescence (FAF), structural spectral-domain optical coherence tomography (SD-OCT), and OCT angiography (OCTA) of patient with pseudodrusen and adult-onset foveomacular vitelliform dystrophy at the vitelliform stage. Multicolor image shows (a) central vitelliform material and FAF (b) shows central hyper-autofluorescence with small circular hypofluorescent areas at the posterior pole. Structural SD-OCT reveals the lesion as hyper-reflective between retinal pigment epithelium/Bruch’s membrane and the ellipsoid zone of the (c) photoreceptors with presence of pseudodrusen. On OCTA, the subretinal material leads to displacement of blood vessels at both the (d) superficial and (e) deep capillary plexus of the retina, associated with apparent vascular rarefaction at the (f) choriocapillaris.
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