Widefield En face Swept Source OCT Imaging of Dry Age-Related Macular Degeneration Subretinal Drusenoid Deposits

Abstract

Purpose: To demonstrate the benefits of 12 X 12 mm widefield en face swept source optical coherence tomography<br /> (SS-OCT) imaging of eyes with age-related macular degeneration (AMD), reticular pseudodrusen (RPD), and<br /> subretinal drusenoid deposits (SDDs).

Methods: Patients with the diagnosis of dry AMD were imaged using a prototype Zeiss 100kHz SS-OCT instrument<br /> (Carl Zeiss Meditec Inc., Dublin, CA) with a central wavelength of 1050nm. SS-OCT volume scans were obtained using a 12 X 12mm raster scan pattern centered on the fovea. In the 12 mm transverse scanning direction, a single Bscan was comprised of 512 A-scans with each A-scan separated by 23.4 μm, 3mm deep, and comprised of 1500 pixels. In the 12 mm vertical scanning direction, a total of 512 B-scans were performed with each B-scan separated by 23.4 μm. Different en face slabs were evaluated and ranging from 0 to 55 μm above the retinal pigment epithelium (RPE). These widefield en face images were then compared with color, autofluorescence, and infrared reflectance images.

Results: A total of 258 subjects were scanned with the prototype SS-OCT instrument and also underwent multimodal<br /> fundus imaging. A total of 133 eyes were diagnosed with RPD based on multimodal imaging, and all of these eyes demonstrated a pattern of SDDs on widefield en face OCT imaging similar to the pattern observed for RPD. The en face slab image that consistently identified SDDs was the 20 μm thick slab with boundaries from 35 to 55 microns above the RPE.

Conclusions: Widefield 12 X 12 mm en face slab imaging with SS-OCT can reliably detect SDDs and could replace<br /> multimodal imaging for the diagnosis of RPD.