Multimodal cellular assessment of the retinal pigment epithelium using an integrated adaptive optics retinal imager

Abstract

Purpose : Noninvasive imaging of the retinal pigment epithelial (RPE) mosaic has been demonstrated through several adaptive optics (AO) -based techniques. However, consistent assessment of the RPE mosaic across the retina remains challenging when relying on a single modality, especially when imaging diseased eyes. Here, an integrated platform for evaluating these modalities side-by-side is demonstrated to assess the RPE mosaic.

Methods : A custom-built multimodal AO scanning light ophthalmoscope (AOSLO) (Comm Biol 2018; 1:189) was enhanced through the integration of a custom-built spectral-domain optical coherence tomography (AOOCT) channel (BOE 2018; 9:4246-4262). The RPE mosaic of three healthy subjects and one choroideremia carrier were imaged through multiple contrast sources including static (darkfield) and dynamic (AOOCT) scattering as well as intrinsic (infrared autofluorescence-IRAF) and extrinsic (indocyanine green-ICG) fluorescence. Imaging was performed across the retina according to published procedures. Following cross-modality alignment of the sequentially acquired AOSLO and AOOCT images, cell centers were identified for analysis of cell spacing.

Results : Using the integrated imaging platform, the RPE mosaic was successfully imaged at various locations across the retina with variation in image quality across channels and locations (see Figure). The co-registered images permit observation of RPE features such as cell boundaries visualized by scattering (darkfield and AOOCT) or intrinsic fluorescence (IRAF) and the heterogeneous ICG fluorescence pattern across cells that together allow for better interpretation and assessment of the RPE mosaic provided through multiple contrast sources. Images obtained from healthy subjects showed general agreement in cell-to-cell spacing across modalities and to published values with some variation across location and modality (see Figure). To demonstrate a clinical application of this approach, images were acquired from a choroideremia carrier where an average increase in cell spacing of 40% compared to healthy subjects was observed consistently across all modalities.

Conclusions : Through the application of this integrated multimodal imager, the RPE mosaic can be assessed through multiple channels that provide both complementary perspectives and cross-validating information.

This is a 2020 ARVO Annual Meeting abstract.