Comprehensive multifunctional retinal imager based on simplified polarization-sensitive Jones matrix OCT

Abstract

Purpose : This study aims at demonstrating a custom-built multifunctional imager based on simplified polarization sensitive (PS) Jones matrix OCT (JM-OCT). Its ability to visualize vascular and retinal pigment epithelial (RPE) pathology is discussed.

Methods : The simplified JM-OCT provides multiple contrasts including OCT, OCT angiography, and degree-of-polarization uniformity (DOPU) that selectively visualizes melanin. Two custom-made image processing methods which fully deploy the multiple contrasts were developed. One of them enables three-dimensional (3D) visualization of melanin associated with RPE (RPE-melanin). The other, pigment-and-flow (PAF) imaging, simultaneously visualizes vascular and RPE pathology. The JM-OCT is also equipped with Lissajous scan mode, which enables motion-free OCT without specific eye-tracking hardware. The system has nearly the same size with commercially available OCT.

238 eye of 162 cases were examined, which includes 114 cases of exudative macular disease.

Results : Fig. 1 shows AMD with drusenoid pigment epithelial detachment (PED), which was imaged with 6 mm × 6 mm raster scan. The RPE-melanin is obtained by the multi-contrast signal processing, and overplayed on the cross-section with red color (c, d). The RPE-melanin is aggregated and thickened at the right half of the PED (c, yellow arrow), while the RPE-melanin is dim or thinned at left and right of the thickening (c, white arrows). The other cross-sections [(b) and (d)], show the hyper-reflective foci (HRF) appeared with RPE-melanin (d, yellow arrow), while the surrounding RPE shows dim or thinned RPE-melanin signal. An en face RPE-melanin thickness map (e) shows high similarity with near-infrared fundus autofluorescence (NIR-FAF, f). This similarity is helpful for 3-D understanding of NIR-FAF findings. I.e., the hyper autofluorescence is originated from the thickened RPE-melanin and the HRF.

Fig. 2 shows a motion-free PAF image of an AMD taken with 3 mm × 3 mm Lissajous scan. The brightness represents OCTA, while the color represents the amount of melanin above the flow as blue for much and red/yellow for less melanin. The abnormal vessel at the center shows patchy damage of RPE.

Conclusions : The comprehensive JM-OCT enables quick understanding of vascular pathology complicated with RPE pathology.

This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.

 

RPE-melanin contrast of drusenoid PED.

 

Motion-free PAF image of AMD.