Purpose
In order to non-invasively investigate the ocular vasculature and retinal and choroidal tissue properties, polarization-sensitive optical coherence angiography (PS-OCA) based on 1-μm Jones-matrix swept-source optical coherence tomography was developed. This study aims at evaluating clinical utility of PS-OCA based on a descriptive case series of macular disease.
Methods
Seven eyes of 5 cases including 1 eye of diabetic retinopathy, 1 eye of angioid streaks, 3 eyes of age-related macular degeneration (AMD), and 2 eyes of geographic atrophy (GA) were imaged with PS-OCA. 4 of 7 eyes had choroidal neovascularization (CNV). 4.5 mm x 4.5 mm or 6 mm x 6 mm areas around the diseased region were scanned with 512 x 1024 A-lines in 6.6 seconds. Structural OCT, Doppler angiography, and degree of polarization uniformity (DOPU) tomography were obtained from a single scan and each tomography represents structure, vasculature and tissue property. Namely, PS-OCA provides a comprehensive set of 3-D tomographies.
Results
Abnormal Doppler signal was observed beneath exudation or pigment epithelium (RPE) detachment in 3 of 4 CNV cases. RPE deformation beneath the exudation was discriminated in 3 of 3 eyes with exudation. RPE location of GA area appeared with high DOPU in 2 of 2 GA eyes, while normal RPE shows low DOPU. The junctional zone of GA shows abnormal segmented low DOPU clusters at the RPE level, while, in structural OCT, RPE appeared as normal. Figure 1 shows a representative case of AMD. CNV was observed in indocyanine green angiography (ICGA) (b). The en face Doppler angiography (e) shows similar appearance with ICGA. Abnormal Doppler signals appeared at the CNV region in power Doppler B-scan (arrows in (h)). This CNV region corresponds to that in ICGA (b). In DOPU image (i), RPE deformation was observed beneath the exudation (arrow). This deformation appeared as a low DOPU (white) crescent in en face DOPU image (arrow in (f)) and this crescent corresponded to the dark rim around CNV in ICGA (b). This RPE deformation corresponded to the leakage area of fluorescence angiography (arrow in (c)).
Conclusions
The PS-OCA noninvasively and simultaneously visualized ocular vasculature and RPE abnormality. The vasculature pattern was well correlated with that of ICGA despite of its noninvasiveness. PS-OCA would enable non-invasive comprehensive investigation of macular diseases.
Keywords: 453 choroid: neovascularization •
701 retinal pigment epithelium •
552 imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)