Abstract
Purpose :
Offset imaging enables cellular-level visualization of retinal structures with unprecedented details not available with other imaging modalities; however, interpretation of such images alone is sometimes difficult and requires other investigations. Simultaneous acquisition of depth-resolved OCT images provides additional insight to help understanding the structures seen in SLO images, particularly in diseased eyes, as described here.
Methods :
The PSI multimodal adaptive-optics retinal imager (MAORI) combines OCT with multi-offset/confocal SLO, both AO corrected. In offset imaging, light forward scattered through the structure imaged in the focal plane is reflected back by the deeper layers and collected through the offset apertures. This interpretation generally assumes that the optical path between the imaged structure and the collecting aperture is relatively isotropic and the offset images reflect mostly the anisotropies of the imaged structure. Such assumption is often not valid, particularly in diseased eyes with pathology such as intraretinal/subretinal fluid or deep retinal deposits that distort the offset aperture light collection and appear as blurred spots.
Results :
OCT imaging, as provided simultaneously with multi-offset SLO in MAORI, enables depth-resolved localization of inner layer structural distortions and facilitates understanding the formations seen in SLO images. The split image (left) shows two large blood vessels and several blurred spots. The OCT image (right) shows good correlation of one of these spots with a focal area of subretinal fluid (red arrow). Sharp details of the blood vessel wall and of multiple capillaries indicate that the SLO focal plane is located in the RNFL and therefore the subretinal fluid appears blurred in the split image, as a nonspecific finding, difficult to distinguish from other types of retinal pathology such as intraretinal cysts or to explain from the SLO image alone. Additional examples will be shown at the meeting.
Conclusions :
Primarily in diseased eyes with multiple structural distortions, interpretation of SLO images can be assisted by simultaneously acquired OCT images that provide additional depth-resolved contrast. Such combination may provide valuable information that enables improved diagnosis of retinal disease from AOSLO images.
This abstract was presented at the 2023 ARVO Imaging in the Eye Conference, held in New Orleans, LA, April 21-22, 2023.