Comparison of 55° Wide-Field Spectral Domain Optical Coherence Tomography and Conventional 30° Optical Coherence Tomography for the Assessment of Diabetic Macular Edema

Abstract

Purpose: To compare conventional 30° spectral domain optical coherence tomography (SD-OCT) with 55° wide-field SD-OCT for the assessment of diabetic macular edema (DME). Methods: This study included 50 DME patients. Both 55° and 30° SD-OCT was conducted. Two readers evaluated scans according to a standardized grading protocol. Intergrader agreement as well as agreement between 30° and 55° SD-OCT were assessed. Results: Intergrader agreement (κ) was strong and ranged from 0.79 to 1.0. Perfect interdevice agreement (κ = 1.0) was found for the detection of intra- and subretinal fluid. Excellent agreement (κ ≥ 0.9) was found for the presence of epiretinal membrane (κ = 0.92) and cotton-wool spots (κ = 0.92). A strong agreement was found for the presence of hard exudates (κ = 0.89) and microaneurysms (κ = 0.81). A moderate correlation was found for ellipsoid zone integrity (κ = 0.69) and configuration of the vitreomacular interface (VMI) (κ = 0.69). A weak agreement was found for retinal pigment epithelium atrophy (κ = 0.51) and external limiting membrane integrity (κ = 0.35). Conclusion: Wide-field OCT imaging may be beneficial for evaluating DME, particularly for assessing the VMI and the integrity of hyperreflective bands.

Automated Retinal Layer Segmentation and Their Thickness Profiles in Healthy Subjects

“…Furthermore, wide-field OCT imaging has been shown to be superior for the assessment of the vitreomacular interface. 10 However, despite these potential benefits, it was previously discussed that morphological alterations such as hard exudates may be missed using 55° wide-field imaging. 10 This might be explained by the fact that there is a higher horizontal resolution of 11.74 µ m/pixel in the conventional OCT scans using the high-speed mode compared with 19.95 µ m/pixel in the high-speed mode wide-field scans, which may impact the detectability of small lesions on OCT.…”

“… 10 However, despite these potential benefits, it was previously discussed that morphological alterations such as hard exudates may be missed using 55° wide-field imaging. 10 This might be explained by the fact that there is a higher horizontal resolution of 11.74 µ m/pixel in the conventional OCT scans using the high-speed mode compared with 19.95 µ m/pixel in the high-speed mode wide-field scans, which may impact the detectability of small lesions on OCT. However, the single scans may not always be on the exact same location of the retina, and therefore, a small, singular alteration may be missed on one of the scanning patterns.…”

“…The horizontal area scanned (25°) and the distance between the scans (240 µ m) and the number of section scans (31) were equal for the 55° and the 30° volume scans, and only the vertical extension (30° vs. 55°) differed between both scanning patterns. 10 Each scan was being averaged nine times. The 55° high-speed wide-field volume scan pattern thus consisted of a 55° × 25° vertical raster scan, whereas the 30° high-speed volume scan pattern consisted of a 30° × 25° vertical raster scan.…”

“…This analysis revealed a strong interdevice agreement but also found that the wide-field OCT may be beneficial when evaluating the vitreomacular interface. 10 …”

Wide-field optical coherence tomography imaging in diabetic retinopathy

“…So far, our focus has been the macular area, however, with advancing imaging modalities such as wide-field OCT acquiring larger field of view up to 100 degrees, our understanding has expanded up to the peripheral retina. 9,10 Wide-field OCT (WF-OCT) can provide details of macula and retinal periphery at a single scan.…”