Figure 1.
Infrared reflectance (IR) image of lesions: IR image (left), Reticular pseudodrusen (RPD) lesions highlighted by a masked retinal specialist using ImageJ software (NIH, Bethesda, MD) with inset of the area providing a magnified view (1a, right).
Figure 2.
Infrared reflectance (IR) image (top left), En Face SD OCT Choroidal Sub-Layer C-Scan (top right).
C-scan image with areas corresponding to the retinal vessels removed using ImageJ software (visible in white, bottom left), and pixel intensity thresholded C-scan using ImageJ software (choroidal vessels in black; bottom right)
Figure 3.
Flowchart demonstrating the review and selection process for the patients included in the study.
Figure 4.
Percentage of RPD and Control RPD lesions
(randomly placed dots) overlying the choroidal vasculature. An average of 49.6±4.3% of RPD lesions were overlying the choroidal vasculature which was significantly higher than the 45.4±3.9% of control lesions. (p = 0.014).
Figure 5.
Distribution of the RPD and control RPD lesions (randomly placed dots) at different distances from the choroidal vasculature (measured in pixels).
Among RPD and control lesions, there was a significantly greater percentage of RPD lesions lying between 1–3 pixels from the choroidal vessels (*, difference 4.2%, p = 0.014) while there was a significantly greater percentage of controls at ≥7 pixels (†, difference 3.6%, p = 0.002) away from the choroidal vessels.
Figure 6.
Correlation of RPD lesions on IR reflectance to the sub-retinal drusenoid deposits (SDD) on OCT and comparison of regular drusen with SDD on OCT.
6A: IR reflectance (top left), IR reflectance with individual RPD lesions marked in black (top right). En face OCT C-scan (middle left) taken at the level of photoreceptors, as shown on b-scan (bottom) showing the sub-retinal drusenoid deposits (SDD; white lesions, yellow arrows). Middle right panel shows an overlay of the RPD lesions from IR (green dots) onto the en-face scan demonstrating the relative lack of overlap between the SDD and the RPD, with the inset providing a magnified view. OCT B-scan (bottom right) highlighting in purple, the location of the en face section. 6B: shows a different eye, which has SDD as well as small hard drusen. Hard drusen are marked by yellow arrows on the C scan (middle left) and the B-scan (bottom left). On en face OCT, hard drusen appear as well defined distinct white lesions surrounded by a ring of hypo-reflectivity (yellow arrows on B-scan and en face images). In contrast, SDD (marked by red arrows on the B-scan and en face images) have relatively indistinct borders, occur in clusters and appear to blend into an isointense background. OCT B-scan (bottom right) highlighting. in purple, the location of the en face section.
Figure 7.
RPD lesions correlate with choroidal vasculature.
IR reflectance RPD lesions shown as black dots (top left) and en face OCT C-scan (top right). Overlay of the RPD lesions and the thresholded C-scan highlighting the choroidal vasculature show an association between the location of the RPD lesions and the choroidal blood vessels (bottom). Of the 751 RPD lesions in this image, 31% were over the choroidal vasculature (n = 233). Of the lesions over the stroma (n = 518), 57.34% were between 1–3 pixels, 28.76% between 4–6 pixels, and 13.9% were ≥7 pixels away from the choroidal vasculature.