Vascularized drusen: a cross-sectional study

Abstract

Background: To investigate whether neovascularization may arise and be detectable in drusen, as reported in histopathologic studies, by OCTA prior to developing exudation and to assess its prevalence in a cohort of patients with intermediate AMD.

Methods: Retrospective cross-sectional study of 128 patients with intermediate AMD recruited as part of a separate ongoing clinical trial conducted at multiple large tertiary referral retina clinics. One hundred and twenty-eight consecutive patients with exudative AMD in one eye and intermediate non-exudative AMD in the fellow eye were enrolled and analyzed between September 2015 and March 2017.

Results: SD-OCTA identified vascularization within drusen in 7 of 128 eyes, for a prevalence of 5.5%. A total of 12 instances of vascularized drusen were noted. Out of the 12 vascularized drusen noted, 7 were located in the parafoveal region or subfoveal region and 5 was in the extrafoveal region. 9 of 12 instances of vascularized drusen exhibited a uniform sub-RPE hyperreflectivity, whilst 3 of 12 exhibited more heterogenous reflectivity. In all 12 instances, FA images failed to identify the neovascular nature of vascularized drusen.

Conclusions: Our results demonstrate the utility of SD-OCTA for the diagnosis of vascularized drusen in patients with intermediate non-exudative AMD. Longitudinal studies are needed to delineate the evolution and conversion risk of these lesions over time, which can be of substantial clinical relevance.

Keywords: Age-related macular degeneration; Optical coherence tomography; Optical coherence tomography angiography; Retina; Retinal imaging; Vascularized drusen.

Fig. 1

Vascularized druse on multimodal imaging. A typical yellow drusenoid lesion is noted on the color fundus image (c red arrow). On FA, there is minimal staining (d–f red arrow). Optical coherence tomography demonstrates a dome-shaped drusenoid retinal pigment epithelium (RPE) elevation with homogenous sub-RPE hyperreflectivity. Optical coherence tomography angiography en face image (a) shows a neovascular network, which corresponds with the flow signal (b) located within the drusenoid lesion. Manual segmentation of the RPE and Bruch’s membrane was used to clearly visualize the neovascular network

Fig. 2

Vascularized druse on multimodal imaging. A typical yellow drusenoid lesion is noted on the color fundus image (c red arrow). On FA, there is minimal staining (d–f red arrow). Optical coherence tomography demonstrates a dome-shaped drusenoid retinal pigment epithelium (RPE) elevation with a heterogenous multi-laminar sub-RPE hyperreflectivity. Optical coherence tomography angiography en face image (a) shows a neovascular network, which corresponds with the flow signal (b) located within the drusenoid lesion. Manual segmentation of the RPE and Bruch’s membrane was used to clearly visualize the neovascular network

Fig. 3

Vascularized druse on follow up. Vascularized druse identified at baseline (a) with development of a low-lying pigment epithelial detachment and subretinal fluid at 6 months follow up (b). Another instance of vascularized druse identified at baseline (c) with persisting vascularity within the lesion at 2 years follow up (d)

Fig. 4

Example of artifact when identifying vascularized drusen. An en face optical coherence tomography angiography image of the superficial plexus is shown (top). The corresponding optical coherence tomography image of the cross section is shown with flow overlay (bottom). The red arrow in the bottom image demonstrates an example of projection artifact, originating from the blood vessel in the superficial image (red arrow; top image)