For exudative AMD, we evaluated a range of pathologic changes, as described in Methods. In both GDx and PS-SD-OCT, polarimetry findings in exudative AMD emphasized different aspects of features and were related to the progression of the disease.
Five patients with RPE detachments were evaluated for this study (
Table 1 ,
Fig. 2 ). Color images showed RPE detachments and surrounding exudation
(Fig. 2A) . Average reflectance images clearly showed areas with RPE detachments as well, demarcated low-intensity areas that typically indicate the presence of fluid
(Fig. 2B) . In phase-retardation maps of the GDx, macular bowtie patterns were observed
(Fig. 2C) . The depolarized light images, similar to the average reflectance images, indicated RPE detachments surrounded by fluid, but there was neither extensive pigment mottling of the retinal pigment epithelium nor evidence of retinal vascular anomalous complex activity indicating retinal damage
(Fig. 2D) . In the intensity images of OCT B-scan, the RPE detachments were clearly observed, and the microstructures of retinal layers from internal limiting membrane to retinal pigment epithelium were well preserved
(Fig. 2E) . In the B-scan cumulative phase-retardation images of PS-SD-OCT, polarization scramble at the RPE layers was clearly observed and implied that microstructures of retinal pigment epithelium were well preserved
(Fig. 2F) . This polarization scramble was also detected in the en face retardation image of PS-SD-OCT
(Fig. 2G) . In other retinal layers, retardations were low and constant throughout the retinas except in RPE layers, and there were no obvious abnormal birefringence at the RPE detachments in the PS-SD-OCT images.
We evaluated the three patients with early-stage exudative AMD with predominantly classic CNV (
Table 1 ,
Fig. 3 ). All patients noticed visual disturbances no more than 2 months before the test. Fluorescein angiograms demonstrated the areas of leakage
(Fig. 3A) . Average reflectance images of the GDx visualized the fluids in CNVs as low-intensity areas, with the surrounding exudates as bright features
(Fig. 3B) . Macular bowtie patterns in the phase-retardation maps of the GDx were observed; however, the contours were disrupted at the areas with exudation
(Fig. 3C) . The depolarized light images visualized CNVs as high-intensity areas surrounded by low-intensity areas
(Fig. 3D) . The intensity images of B-scan OCT showed CNVs as highly reflective lesions that elevated the overlying retinas, and the RPE layers were disrupted in a corresponding manner
(Fig. 3E) . CNVs had low birefringence in the cumulative phase-retardation images of B-scan PS-SD-OCT
(Fig. 3F) . This implied that the CNV contained only a small fibrotic change because increased amounts of proteins, such as collagen or fibrin, provide a strong birefringence signal well known in wound healing.
29 Cumulative phase-retardation values at the CNVs were distributed from 20° to 42°. The RPE layers were disrupted to varying degrees, but the depths of the layers were fairly uniform, whereas the elevations of the overlying retinas varied greatly. Comparison of the left and right portions of the lesion and of the retinal pigment epithelium beneath the flatter portion compared with the more sloped portions of the lesion indicated that the changes shown for the deeper layers did not result solely from the signal being blocked by the different pathologic structures through the fluid associated with the lesion
(Figs. 3E 3F) . These findings implied that the microstructure of retinal pigment epithelium was damaged to varying degrees beneath the lesion.
We evaluated a the eye of a patient with CNV and RPE tear (
Table 1 ;
Fig. 4 ). Indocyanine angiography clearly showed the RPE tear as a hypofluorescent area adjacent to CNV
(Fig. 4A) . The average reflectance images and the depolarized light image of GDx showed the RPE tear as a high-intensity area, consistent with previous near infrared imaging
30 (Figs. 4B 4D) . In the depolarized light image, an area of CNV was shown as a spotted high-intensity area
(Fig. 4D) , and the CNV and RPE tear were surrounded by a low-intensity area. The macular bowtie pattern in the phase-retardation map of the GDx was disrupted in the area with exudation
(Fig. 4C) . The intensity image of the B-scan OCT showed the CNV as a highly reflective lesion, and this lesion had low birefringence in the PS-SD-OCT image
(Figs. 4E 4F) . The cumulative phase-retardation value at the CNV was 31°. The RPE tear could be observed in the inferior-to-superior intensity image of B-scan OCT and was clearly demonstrated as a discontinuity of intensity and of polarization scramble in PS-SD-OCT images
(Figs. 4G 4H) .
We evaluated three eyes at the end stage of exudative AMD with disciform scars (
Table 1 ;
Fig. 5 ). Color images showed the light-scattering properties of scars
(Fig. 5A) . Average reflectance images of the GDx showed the disciform scars as high-intensity areas demarcated with neighboring low-intensity areas
(Fig. 5B) . In the phase-retardation maps of the GDx, abnormal strong birefringence at the disciform scars—but no obvious macular bowtie—was observed
(Fig. 5C) . The depolarized light images showed disciform scars as low-intensity areas that included smaller bright regions surrounded by pigment changes
(Fig. 5D) . In the intensity images of B-scan OCT, highly reflective layers were observed in deep retinal layers, and the RPE layers were hardly distinguishable
(Fig. 5E) . In the phase-retardation images of B-scan PS-SD-OCT, areas of abnormal birefringence were observed corresponding to these highly reflective layers, and polarization scramble at the RPE layer could not be detected
(Fig. 5F) . Cumulative phase-retardation values at the CNVs were distributed from 115° to 127°. In the cutaway volumes of phase-retardation images of PS-SD-OCT, there were sharp changes across the retinas that were not seen in normal eyes
(Fig. 5G) . Areas with abnormal birefringence corresponded to areas with disciform scars and areas with abnormal birefringence in GDx images.
In an eye with recurrence after photodynamic therapy, two distinctive exudative lesions were observed in the color fundus photograph (
Table 1 ;
Fig. 6A ). One was a disciform scar and the other was a new exudative lesion, as demonstrated by fluorescein angiography
(Fig. 6B) . The polarization properties of these exudative lesions were completely different. The average reflectance image of GDx showed the disciform scar as high-intensity area and the new exudative lesion as a low-intensity area
(Fig. 6C) . In the phase-retardation map, the disciform scar had a clear-cut region of strong birefringence, and the new lesion showed only weak birefringence. No macular bowtie was present
(Fig. 6D) . In the depolarized light image, the margin of the new lesion could be detected, and a choroidal vessel could be visualized in the area with the disciform scar
(Fig. 6E) . In the intensity image of B-scan OCT, both lesions appeared as highly reflective areas and did not clearly distinguish the contents of two lesions
(Fig. 6F) . The phase-retardation image of the B-scan PS-SD-OCT clearly distinguished the contents of two lesions. The area with the disciform scar showed clearly abnormal birefringence, whereas the new exudative lesion showed only subtle birefringence differences from the surrounding retina
(Fig. 6G) . The cumulative phase-retardation value at the new CNV was 39°, but at the scar it was 137°. The polarization scramble at the RPE layer was difficult to detect. In the cutaway volume of phase-retardation images of PS-SD-OCT, again strong changes were found across the retina
(Fig. 6H) . The area with abnormal birefringence corresponded to the area with the disciform scar and the area with abnormal birefringence in the GDx image.
We compared mean cumulative phase retardation across patients with the lesions that occurred within 2 months in one group (patients 6–9) and the older disciform scars in another group (patients 10–12;
Fig. 7 ). Retardation values at the disciform scars were significantly higher than CNVs (
P = 0.020, Mann-Whitney
U test; Fig. 8).