Purpose
We introduced recently developed multifunctional Jones matrix optical coherence tomography (MJ-OCT). Using the system capable of measuring Doppler phase shift and phase retardation, simultaneous high contrast blood flow imaging and retinal, choroidal and scleral birefringence investigation was achieved.
Methods
MJ-OCT is capable of full Jones matrix measurement of in vivo human eye by passive polarization multiplexing and polarization diversity detection. Newly developed advanced signal processing enables high-sensitive flow imaging. 10 eyes of 5 subjects without marked posterior disorder were involved in this study. By using MJ-OCT, 6 mm × 6 mm macular and optic nerve head (ONH) areas were scanned with 512 A-scans × 1024 B-scans in 6.6 seconds. For phase retardation imaging with high signal-to-noise ratio, the B-scan was repeated four times at each location, and Doppler phase shift was calculated among the repeated B-scans having a time-separation of 6.4 ms. This Doppler measurement protocol enables the minimum detectable Doppler velocity of 0.4 μm/s. In addition, degree of polarization uniformity (DOPU) was calculated for identifying the retinal pigment epithelium (RPE) which is known to have low DOPU.
Results
The figure shows a representative case of myopic eye. In en face OCT projection (a), a myopic conus is appeared as hyper scattering crescent. The similar appearance was found with 4 of 6 myopic eyes. In the OCT projection, some of the choroidal vessels only dimly appeared (6 of 10 eyes) or were not revealed (4 of 10 eyes). On the other hand, the projection of power of Doppler shift (b) clearly shows the choroidal vessels as well as the retinal vessels (10 of 10 eyes). In addition, birefringence of lamina cribrosa and scleral canal rim at the edge of the ONH are obviously identified in the phase retardation image (d) with strong alteration of phase retardation along the depth, which indicates strong birefringence (10 of 10 eyes). The characteristic of RPE is evidently observed through the DOPU image (e) in which the RPE appeared as yellow to green (low DOPU).
Conclusions
Besides the structural information from OCT, detailed vasculature and birefringence properties inside the retina were achieved by the MJ-OCT. MJ-OCT was found to have potentials to non-invasively reveal structural, vasculature, and tissue properties of deep posterior part of the eye.
Keywords: 688 retina •
452 choroid •
577 lamina cribrosa