Article
Imaging of focally increased pigment in early and Intermediate AMD – analysis of longitudinal alterations
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Published: | May 30, 2012 |
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Purpose: Focally increased pigment represents a high-risk factor for AMD progression. Purpose of the study was to determine alterations of increased pigment in early and intermediate AMD by means of multimodal imaging over time.
Methods: 18 eyes with early or intermediate AMD (AREDS-classification) of 14 patients (mean age 74) were included. Imaging including color fundus photography (CFP) (Visucam), cSLO-fundus autofluorescene (FAF) and spectral-domain optical coherence tomography (SD-OCT) (Spectralis HRA+OCT) was performed at baseline examination (t0) and one year later (t1). After semi-automated alignment of different imaging modalities and examination dates, each increased pigment was topographically correlated with the focal FAF- and SD-OCT-signal.
Results: Increased pigment was funduscopically visible in 8 of 18 eyes at t0 and t1. At t1, 27 loci of increased pigment were identified, of which 11 showed an increase, 5 a decrease and 11 no change in size over time. FAF at t0 revealed an increased signal in 14 and a normal signal in 6 cases. FAF signal altered over time in 3 cases: from increased at t0 to normal at t1. SD-OCT imaging showed focal hyperreflectivity above band 4 in 8 and only at band 4 level in 2 cases. At 4 sites of increased pigment SD-OCT revealed migration of the hyperreflective signal in inner retinal direction.
Conclusion: Increased pigment visible in CFP correlates with different alterations in FAF and SD-OCT. By means of multimodal imaging dynamic change over time alluding to migration of RPE cells and compromised outer retinal integrity can be identified.