Photo Credit: miodrag ignjatovic

The following is a summary of “Comparison between OCT B-scan and En face Imaging for the diagnosis of early macular atrophy in age-related macular degeneration,” published in the October 2024 issue of Ophthalmology by Cheng et al. 

Researchers conducted a retrospective study to compare the gradings of complete retinal pigment epithelium and outer retinal atrophy (cRORA) and incomplete retinal pigment epithelium and outer retinal atrophy (iRORA) on spectral domain optical coherence tomography (SD-OCT) B-scans with the grading of persistent choroidal hypertransmission defects (hyperTDs) on swept-source OCT angiography (SS-OCTA) en face images.  

They performed a same-day 6 × 6 mm macular scans using SD-OCT (Spectralis® Heidelberg) and SS-OCTA (PLEX® Elite 9000) instruments in patients with late nonexudative age-related macular degeneration (AMD), SS-OCTA and SD-OCT en face images were generated from a sub-retinal pigment epithelium slab positioned 64-400 μm below Bruch’s membrane. SD-OCT B-scan gradings, including neighboring B-scan inspection for cRORA and iRORA diagnosis, were performed at the Moran Eye Center. The en face image gradings to identify persistent choroidal hyperTDs were performed at the Bascom Palmer Eye Institute and Tel Aviv Medical Center.   

The results showed a high level of agreement (99.6%) between the gradings of cRORA lesions and persistent hyperTDs. However, 27.4% of iRORA lesions were identified within persistent hyperTDs. This discrepancy arose because 27.5% of iRORA lesions were diagnosed on B-scans as having a greatest linear horizontal dimension of fewer than 250 micrometers (µm), but en face, images revealed that these B-scan-defined iRORA lesions had the greatest linear dimensions in the non-horizontal direction that were equal to or greater than 250 µm.  

They concluded en face OCT imaging effectively identified cRORA lesions and emphasized the necessity of obtaining dense raster B-scans to accurately assess the extent of iRORA lesions. 

Source: ajo.com/article/S0002-9394(24)00473-2/fulltext