Article
High-risk Fundus Autofluorescence Phenotype in Aeographic Atrophy – Spectral domain OCT characteristics
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Authors
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Monika Fleckenstein
- University Eye Clinic Bonn
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S. Schmitz-Valckenberg
- University Eye Clinic Bonn
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S. Kosanetzky
- University Eye Clinic Bonn
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C. Martens
- University Eye Clinic Bonn
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C. K. Brinkmann
- University Eye Clinic Bonn
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F. G. Holz
- University Eye Clinic Bonn
| Published: | September 21, 2010 |
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Outline
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Background: Patterns of abnormal fundus autofluorescence (FAF) in the perilesional zone of geographic atrophy (GA) in AMD serve as predictors for individual disease progression. The "diffuse-trickling" phenotype thereby shows the highest progression rate (Holz et al. AJO 143:463-72, 2007). In this study, morphological alterations of thei high-risk phenotype are analysed by spectral domain (SD)-OCT.
Methods: Thirty-six eyes of twenty patients (mean age 64.6±9.3 years) with the “diffuse-trickling” phenotype were examined by simultaneous SD-OCT and confocal scanninglaser ophthalmoscopy (Spectralis, Heidelberg Engineering). Progression rate of atrophy lesions was measure by semi-automated image processing. Morphological alterations in the perilesional zone, at the GA border, and eithin the atrophic lesion were quantitatively analysed.
Results: Eye with the “diffuse-trickling” phenotype, exhibited a ‘splitting’ of SD-OCT band 4 (retinal pigment epithelium [RPE]/Bruchs membrane [BM]), that was most obvious directly at the border but also in distance to the atrophic lesion. Within the atrophy, in extension of the inner part of band 4, there was a fine discontinues band, that faded with the distance to the border and with time, respectively. A splitting of band 4 was detected in a minority of eyes with other GA phenotypes, but, when seen this was less widespread and less pronounced.
Discussion: The characteristic finding in the “diffuse-trickling” phenotype – the splitting of OCT band 4 – may be due to excessive, widespread accumulation of sub-pigmentepithelial material. Possible morphological correlate are “basal laminar deposits” (BLamD) which could previously not be visualized in vivo. Their vertical extent may correlate with the degree of RPE- and photoreceptor degeneration and they may persist within the atrophic lesion. Excessive BLamD accumulation may induce aggressive GA progression with time and may therefore explain phenotypic characteristics of the “diffuse-trickling” phenotype.
