Ординатура / Офтальмология / Английские материалы / Atlas of Fundus Autofluorescence Imaging_Holz, Schmitz-Valckenberg, Spaide, Bird_2007

158 Steffen Schmitz-Valckenberg et al.

Fig. 12.3  Top row: Fundus autofluorescence (FAF) image and near-infrared reflectance image of the left eye of a patient with geographic atrophy secondary to age-related macular degeneration. There is extensive parafoveal atrophy with foveal sparing. Visual acuity was 6/9 in the left eye (fellow eye 6/60). However, the patient reported a marked increase in reading difficulties 2 months before presentation. FAF imaging indicates that the residual foveal island is obviously too small for reading words or text, while in routine clinical examination good central visual acuity is achieved. Middle and bottom rows: Illustration of the influence of baseline atrophy and FAF changes on atrophy progression over time. Although both eyes have similar sizes of baseline atrophy (left column), there is a great difference in the size of atrophy at the follow-up examination (review period for both examples about 6 years; right column), suggesting that baseline atrophy does not represent a major risk factor for atrophy progression. However, the area with increased FAF at baseline (delineated by the polygon [convex hull]) was much larger for the eye that showed a more rapid spread of atrophy

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Fig. 12.4  Classification of fundus autofluorescence (FAF) patterns in the junctional zone in patients with geographic atrophy (GA) due to age-related macular degeneration. Eyes with no increased FAF intensity at all are graded as “none.” The eyes with increased FAF are divided into two groups depending on the configuration of increased FAF surrounding the atrophy. Eyes showing areas with increased FAF directly adjacent to the margin of the atrophic patch(es) and elsewhere are called diffuse and are subdivided in five groups: top row, left to right: fine granular, branching; bottom row, left to right: trickling, reticular. and fine granular with punctuated spots. Eyes with increased FAF only at the margin of GA are split into three sub-types: focal, banded, and patchy, according to their typical FAF pattern around atrophy

Fig. 12.5  Illustration of the relationship between specific fundus autofluorescence (FAF) phenotypes and atrophy progression for patients with geographic atrophy due to age-related macular degeneration (part I—slow progressors) showing the baseline FAF image (left) and follow-up FAF image (right) for each eye, respectively. Eyes with no abnormal FAF changes (top row, atrophy progression 0.02 mm2/year, follow-up 12 months) and with only small areas of focally increased autofluorescence at the margin of the atrophic patch (bottom row, 0.36 mm2/year, follow-up 15 months) usually have a very slow progression over time

162 Steffen Schmitz-Valckenberg et al.

Fig. 12.6  Illustration of the relationship between specific fundus autofluorescence (FAF) phenotypes and atrophy progression for patients with geographic atrophy due to age-related macular degeneration (part II—rapid progressors) showing the baseline FAF image (left) and follow-up FAF image (right) for each eye, respectively. Eyes with the diffuse FAF pattern (top row, 1.71 mm2/year, follow-up 12 months) and with the banded type (middle row, 2.52 mm2/year, follow-up 18 months) of increased FAF surrounding atrophy are characterised by rapid atrophy enlargement. Very rapid atrophy progression can be observed in eyes with the diffuse trickling FAF pattern (bottom, 3.78 mm2/year, follow-up 18 months)

166 Felix Roth, Frank G. Holz

variable FAF phenomena [5, 7–9]. Distinct variations of the normal background FAF signal in the area of the PED can be visualised, which are not detectable using conventional imaging techniques such as fundus photography, fluorescein, or indocyanine green angiography.

Changes in FAF intensities in patients with PED secondary to AMD can be classified into four groups. The majority of PEDs show a corresponding evenly marked and distributed increase of the FAF signal over the lesion, surrounded by a well-defined less autofluorescent halo delineating the entire border of the lesion (Figs. 13.1c, 13.2c). It has been speculated that the ring of decreased FAF at the edge of the PED may reflect beginning organisation of the lesion or may originate from absorption effects of sub-neurosensory extracellular fluid. There are also PEDs with an intermediate (Fig. 13.3d) or a decreased FAF signal over the lesion (Fig. 13.5c), which may or may not correspond to areas of RPE atrophy or fibrovascular scaring. Rarely, a PED shows a cartwheel pattern with corresponding hyperpigmented radial lines and a diminished autofluorescence signal between those lines (Fig. 13.6c).

Of note, changes in the FAF signal in the presence of PEDs are not necessarily caused by alterations of RPE lipofuscin accumulation. Other dominant fluorophores with similar excitation and emission spectra inside the PED, such as extracellular fluid or degraded photoreceptors, may be present and contribute to typical patterns with abnormal FAF intensity. The molecular species in the sub-RPE space remain to be identified. Overall, different FAF phenotypes may reflect not only different stages in the evolution of a PED (Fig. 13.4) but also heterogeneity on a cellular and molecular level in the disease process, and may thus be relevant for future molecular genetic analyses. Future longitudinal investigations are necessary to assess whether different phenotypic patterns are of predictive significance.

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Fig. 13.1a–c  Colour, fluorescein angiogram, and corresponding fundus autofluorescence (FAF) image showing a detachment of the retinal pigment epithelium due to age-related macular degeneration with increased FAF signal over the lesion and a surrounding area of decreased autofluorescence. Note the notch indicating occult choroidal neovascularisation in the fluorescein angiogram