Abstract
Purpose :
To test OCT-Leakage (OCT-L), a new method of analysis and mapping sites of lower optical reflectivity (LOR), in eyes with neovascular AMD (nAMD) and retinal edema, to identify and locate disease-related abnormal fluid and its change after anti-VEGF therapy.
Methods :
Prospective OCT-L analysis of a cohort of nAMD cases immediately before and 1-week after anti-VEGF therapy. Raw scan data from OCT Cirrus AngioPlex (ZEISS,Dublin,California,USA) was exported and used to calculate lower than normal optical reflectivity maps (OCT-L maps). LOR maps were collected for the whole retina and layer by layer, after semi-automated segmentation procedure developed in-house. The LOR area ratio, representing the LOR distribution in a given area of the retina, was obtained for all layers and the whole retina. Macular cube acquisition for automated central retinal thickness and OCTA were performed. LOR ratios of the first visit (V1) and the 1-week post-treatment visit (V2) were compared. Retinal and layer by layer thickness obtained by semi-automated segmentation was compared between visits and its change correlated to LOR ratio change.
Results :
Twenty eyes with nAMD on anti-VEGF treatment were included. OCT-L maps were able to delineate the location of intra and subretinal fluid. The LOR ratio of the whole retina decreased from V1 to V2 (0.43 to 0.32 in central subfield). Layer analysis showed that this decrease took place mainly in the external outer-segments (OS)-RPE layer and RPE-Bruch layer, where the neovascular process is located, with minimal change in the LOR of other retinal layers, implying a reduction in disease-related abnormal fluid after treatment. Retinal thickness (RT) obtained from segmentation decreased from V1 to V2 (p=0.02) and this was due to the external layers (OPL, ONL+IS, OS-RPE, RPE-Bruch). Decrease in automated central RT was also significant (p=0.006). Correlation between RT change and LOR ratio change from V1 to V2 was found to be strong and positive in the OPL, OS-RPE and RPE-Bruch layers and for the whole retina (p<0.05).
Conclusions :
Mapping of LOR sites in eyes with nAMD with OCT-L demonstrated the extent and location of fluid in the external retinal layers and its decrease after treatment. The possibility of complementarity between OCT-L mapping and OCTA shows potential to contribute to patient management in this setting.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.