Colocalization of pseudodrusen and subretinal drusenoid deposits using high-density en face spectral domain optical coherence tomography.

PURPOSE: To determine if pseudodrusen seen in fundus photography, particularly infrared scanning laser ophthalmoscopy, colocalize with subretinal drusenoid deposits imaged by optical coherence tomography.
METHODS: The patients were scanned with spectral domain optical coherence tomography having an A-scan spacing of 5.9 μm and a B-scan spacing of 11 μm. En face slabs were derived from this data set at distances 50 μm to 90 μm above the Bruch membrane reference plane to image the subretinal drusenoid deposit and also 6 μm below Bruch membrane to image the level of the choriocapillaris. The corresponding infrared scanning laser ophthalmoscopy image was registered to the optical coherence tomography data by aligning the retinal blood vessels in each imaging modality through elastic warping.
RESULTS: All ten eyes of nine consecutively imaged patients showed a concordance between the pseudodrusen and the subretinal drusenoid deposit in every case. At their more internal aspects, subretinal drusenoid deposits were generally isolated foci of reflectivity and with decreasing distances above the reference plane appeared to become broader, reaching confluence with neighboring deposits analogous to a topographical map of mountains. In contrast to previous reports based on optical coherence tomography, and in keeping with histologic evaluation, no patient was seen to have widespread abnormalities in choriocapillaris imaging.
CONCLUSION: This study, using an unprecedented scan density, showed that pseudodrusen appearance can be attributed to subretinal drusenoid deposits. The results of this study have widespread applicability in the understanding of age-related macular degeneration and the associations of the lesions with other structures in the outer retinal neurovascular unit.