Multimodal Imaging, OCT B-Scan Localization, and En face OCT Detection of Macular Hyperpigmentation in Eyes with Intermediate AMD

Abstract

Purpose : Multimodal imaging was used to identify and characterize the cause of hyperpigmentation seen on color fundus images (CFIs) in eyes with intermediate age-related macular degeneration (iAMD).

Methods : At the Bascom Palmer Eye Institute, a retrospective review of a prospective observational case series of eyes with iAMD was performed. CFIs with macular hyperpigmentation were compared with same day images obtained using fundus autofluorescence (FAF), near infrared reflectance (NIR) and swept-source optical coherence tomography (SS-OCT) imaging. Two SS-OCT en face slabs were generated for analysis: a retinal slab to identify hyper-reflective foci within the retina and a slab from beneath the retinal pigment epithelium (sub-RPE slab) that was used to detect regions that cause decreased light transmission into the choroid, also known as hypo-transmission defects (hypoTDs). All images were registered to allow for qualitative comparisons by two independent graders.

Results : Six representative cases from this study are shown. Compared with CFIs, FAF imaging appeared to be the least sensitive method for the detection of hyperpigmentation while NIR and SS-OCT imaging reliably detected these foci of hyperpigmentation. While NIR imaging detected most of the hyperpigmentation seen in CFIs, SS-OCT imaging detected all the areas of hyperpigmentation, and these areas were anatomically localized by using both en face and B-scan images. En face OCT slabs of the retina and sub-RPE region were registered to the CFIs and areas of hyperpigmentation were shown to correspond to hyper-reflective foci in the retina and regions of thickened RPE seen on OCT B-scans. While both hyperpigmentation and early atrophic lesions appeared bright on NIR imaging, en face SS-OCT imaging was able to distinguish these lesions since hyper-pigmentation appeared dark and early atrophic lesions appeared bright on the sub-RPE slab.

Conclusions : En face OCT imaging in conjunction with OCT B-scans were able to reliably identify and localize the hyperpigmentation seen on CFIs, and unlike previous reports that associated hyperpigmentation with intra-retinal hyper-reflective foci, we found that this hyperpigmentation could also be associated with a thickened RPE.

This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.

 

Figure 1. Multimodal imaging of hyperpigmentation (arrows). (A)CFI. (B)FAF. (C)NIR. (D)SS-OCT sub-RPE slab. (E)SS-OCT retinal slab. (F, G)B-scans.