Abstract

DO.18.02

In-vivo imaging of reticular drusen with simultaneous cSLO and SD-OCT

Julia Steinberg, Steffen Schmitz-Valckenberg, Monika Fleckenstein, Frank G. Holz
Universitäts-Augenklinik Bonn

Objective: Reticular drusen are known as funduscopically visible networks with yellowish round or oval irregularities at the posterior pole in patients with age-related macular degeneration (AMD). Histopathology proposes changes in the choriocapillaris as morphological substrate. In this study, we investigated structural changes of different retinal layers in patients with reticular drusen using high-resolution in-vivo imaging.
Methods: Morphological alterations were analyzed in 15 scans of 15 AMD patients (age 79,8 ± 5,6) with reticular drusen which had been obtained by simultaneous imaging with a combined instrument (Spectralis HRA+OCT, Heidelberg Engineering), allowing for both spectral-domain optical coherence tomography (SD-OCT, 870 nm, 40.000 A-Scans/seconds) and confocal scanning laser ophthalmoscopy (cSLO; exc: 488 nm; em > 500 nm und exc. 830 nm). Individual anatomical layers in SD-OCT were evaluated according to Pircher et al. (IOVS 2006). The linear dimension of the reticular drusen pattern was independently assessed on both cSLO and corresponding SD-OCT scans. In addition, the diameter of 10 individual reticular drusen per patient was determined.
Results: SD-OCT scans revealed marked changes at the level between the RPE/Bruch’s membrane complex to the interface of inner and outer photoreceptor segments with a wavy pattern and fusing of bands 2-4. These correlated with a network of halo-like changes in cSLO pictures in all patients (average linear diameter 5990 µm for cSLO versus 5994 µm for SD-OCT, p = 0,7, Wilcoxon-Signed Rank Test). Alterations in the choroid were not detected by SD-OCT. The average distance between bands 2 to 4 over individual drusen was with 86 µm significantly larger as compared to 76 µm in normal subjects (p = 0,02). The average diameter of reticular drusen in the SLO-images was 175 µm ± 91 and therefore in a similar range as previously reported.
Conclusions: As opposed to previous assumptions based on one histopathological case report, this study shows alterations of the outer retina as morphological substrate of reticular drusen using high-resolution in-vivo imaging. Reticular drusen are high-risk markers for the progression of dry AMD, thus their identification is relevant for early diagnosis and future interventional studies.

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