Abstract
Purpose :
To develop ultra-wide field OCT angiography (UW-OCTA) for imaging patients with diabetic retinopathy (DR)
Methods :
UW-OCTA was developed based on a 1060 nm swept source OCTA engine (Plex Elite, Carl Zeiss Meditec. Inc) running at 100 kHz A-line rate with motion tracking mechanism. A montage scanning protocol was designed to enable the UW-OCTA imaging, covering a field of view (FOV) of ~100 degrees. For the montaging scan, 16 cube scans were performed on each patient. Each cube scan covered 6mm×6mm sampled by 500 A-lines × 500 B-frames with 2 repetitions at each B-scan location. Complex OMAG algorithm was used to extract blood flow information. To visualize retinal vasculature, three layers were segmented including vitreous retinal layer (VRL) covering a slab 100 microns above the ILM, superficial retinal layer (SRL) extending from ILM to IPL, deep retinal layer (DRL) from outer border of IPL to outer border of OPL, which were then color-coded to appreciate depth information. Longitudinal scans of DR patients were collected before and after laser/anti-VEGF treatment to show the usefulness of the UW-OCTA in the clinical imaging of DR patients
Results :
3 patients with DR including non-proliferative diabetic retinopathy and proliferative diabetic retinopathy underwent UW-OCTA images before and after laser/anti-VEGF treatment. In comparison with FA, UW-OCTA images provide distinct and detailed visualization of vascular networks over ~100-degree FOV. The neovasculatures located in the peripheral VRL were precisely detected and these neovessels were regressed dramatically after anti-VEGF treatment. The UW-OCTA images showed the macular ischemia and non-perfusion regions in far peripheral region at one scope, which makes it possible to quantify vascular features within all 7 defined EDTRS fields. UW-OCTA images also provided detail information of other vascular features, including microaneurysms and intra-retinal microvascular abnormalities (IRMA), and their locations
Conclusions :
The wide angle OCTA is capable of imaging peripheral retina, comparable with wide-angle fundus image. We have successfully demonstrated the UW-OCTA of DR patients that extends to more than 100-degree view angle, and provides unprecedented vascular details in the peripheral regions. Further studies will be done to quantify OCTA defined by standard EDTRS and find the role in treatment of different macular diseases
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.