Classification of abnormal fundus autofluorescence patterns in the junctional zone of geographic atrophy in patients with age related macular degeneration

Abstract

Aim: To describe and classify patterns of abnormal fundus autofluorescence (FAF) in the junctional zone of geographic atrophy (GA) in patients with age related macular degeneration. Methods: Digital FAF images were recorded in 164 eyes of 107 patients using a confocal scanning laser ophthalmoscope (cSLO; excitation 488 nm, detection above 500 nm) as part of a prospective multicentre natural history study (FAM Study). FAF images were obtained in accordance with a standardised protocol for digital image acquisition and generation of mean images after automated alignment. Results: Image quality was sufficient for classification of FAF patterns in 149 eyes (90.9%) with lens opacities being the most common reason for insufficient image quality. Abnormal FAF outside GA in 149 eyes was classified into four patterns: focal (12.1%), banded (12.8%), patchy (2.0%), and diffuse (57.0%), whereby 12.1% had normal background FAF in the junctional zone. In 4% there was no predominant pattern. The diffuse pattern was subdivided into four groups including reticular (4.7%), branching (27.5%), fine granular (18.1%), and fine granular with peripheral punctate spots (6.7%). Conclusions: Different phenotypic patterns of abnormal FAF in the junctional zone of GA can be identified with cSLO FAF imaging. These distinct patterns may reflect heterogeneity at a cellular and molecular level in contrast with a non-specific ageing process. A refined phenotypic classification may be helpful to identify prognostic determinants for the spread of atrophy and visual loss, for identification of genetic risk factors as well as for the design of future interventional trials.

Lipofuscin- and melanin-related fundus autofluorescence visualize different retinal pigment epithelial alterations in patients with retinitis pigmentosa

“…32 In various degenerative retinal disorders, increased FAF correlated with lipofuscin accumulation, whereas reduced or absent FAF indicated blockage (eg, retinal vessels), loss of RPE cells, or absence of RPE phagocytosis. 26,27,[33][34][35][36][37][38][39][40] The patterns of FAF distribution in RP patients observed in this study are similar to those reported previously. Ophthalmoscopically preserved areas of RPE at the posterior pole correspond to detectable FAF.…”

Predictors for the progression of geographic atrophy in patients with age-related macular degeneration: fundus autofluorescence study with modified fundus camera

“…The FAM-Study Group developed the classification of abnormal FAF according to distinct patterns in the junctional zone of the GA area and identified the following five primary phenotypes based on the presence of increased hyper-autofluorescence: None, Focal, Banded, Patchy, and Diffuse. 15 The Diffuse phenotype was further subdivided into four additional patterns. Holz et al 14 showed that the phenotypic features of FAF abnormalities had a much stronger impact on atrophy progression than any other risk factor that has been addressed in previous studies on progression of GA attributable to AMD, and introduced the 'diffuse trickling' pattern that is associated with an extremely rapid progression of atrophy.…”

“…14 The Fundus Autofluorescence in Agerelated Macular Degeneration (FAM) study group developed a step-wise approach for classifying GA lesions and identified five primary phenotypes based on the presence of increased autofluorescence at the junctional zone of the atrophic patch. 15 Several longitudinal studies based on these phenotypes have demonstrated that distinct FAF patterns are associated with atrophy progression. Bearelly et al 16 categorized the extent of increased autofluorescence, which was termed rim area focal hyper-autofluorescence, in the 500 mm perimeter bordering the GA into three categories.…”

Scanning Laser Ophthalmoscope in the Management of Age-related Macular Degeneration

“…The 'diffuse trickling' subtype showed the fastest rate of expansion, which was twice as fast as other diffuse or banded FAF patterns. 72 Further evidence relating to the significance of FAF patterns in early and atrophic AMD are necessary, but evidence from one of the largest longitudinal studies to date has contributed confirming evidence linking focal and patchy FAF in early AMD as a risk factor for progression to advanced disease. For patients with advanced AMD, the diffuse and banded FAF patterns in the junctional zone of GA appear to be precursors to expansion.…”

“…The FAF patterns identified were defined in an attempt to explain the large variability in rates of GA enlargement among patients that cannot be explained by baseline atrophy or any other risk factor (smoking, lens status, or family history). 68,69,72 The five junctional zone FAF patterns identified, include no change, focal, banded, patchy, and diffuse patterns. The diffuse pattern, in turn,is separated into five different subtypes (see Figure 2).…”