Artikel
Mapping of the retinal pigment epithelium layer in exudative age-related macular degeneration
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Autoren
Veröffentlicht: | 22. September 2004 |
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Gliederung
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Objective
To evaluate a novel technique of three-dimensional mapping of the retinal pigment epithelium (RPE) layer in patients with subfoveal choroidal neovascularizations (CNV) due to age-related macular degeneration.
Methods
Scanning with the retinal thickness analyzer (RTA) was performed in consecutive patients with AMD and subfoveal CNV undergoing fluorescein angiography. A current generation RTA was used to scan a 3x3mm area centered on the fovea in 300ms and generate a three-dimensional area map of the level of the RPE. Included were 18 eyes with classic CNV and 18 eyes with occult CNV and 18 eyes from age-matched normals. Repeatability was assessed by measuring 17 eyes with CNV three times. In 10 patients RTA imaging results were compared to cross-sections obtained by optical coherence tomography.
Results
Distinctive changes in RPE level maps were observed in classic and occult CNV. There was good qualitative correlation between RTA and optical coherence imaging. In classic CNV with the lesion extending over the RPE, only few irregularities in the RPE surface were observed. In contrast, RTA mapping of occult CNV showed a marked anterior displacement of the RPE layer. The RPE map standard deviation indicating surface irregularity differed statistically significantly between the groups with coefficients of variance of 5.9% for controls, 6.1% for classic and 8.8% for occult CNV. Repeatability was very good with foveal retinal thickness measurements having a mean standard deviation of 20 micron and RPE level maps showing only 1.2% coefficient of variance and an intra-class correlation coefficient of 0.87 for triple measurements in CNV patients.
Conclusions
Mapping of CNV lesions with the RTA offers a fast, reproducible method for obtaining three-dimensional morphometric information on changes of the RPE level. Combined with angiography, the additional topographic information of RPE level maps may allow to better understand the pathophysiology and course of different types of CNV and help in the diagnosis and selection of therapy.