Repeatability of Choroidal Vascularity Index Measurements Using Directional Optical Coherence Tomography Images

Abstract

Purpose: To investigate the repeatability of choroidal vascularity index (CVI) measurements in centered and decentered (regarding pupil entry position of the beam) directional subfoveal optical coherence tomography (OCT) scans with (CVI1) and without (CVI2) brightness adjustment. Methods: Thirty-two eyes of 32 healthy volunteers were included in this prospective study. First, the fovea was evaluated by a single horizontal enhanced depth imaging OCT scan in a centered direction. Then, the same subfoveal horizontal line was scanned in a decentered direction. The agreement between CVIs obtained from these centered and decentered directional OCT scans was investigated using Bland–Altman analysis and intraclass correlation coefficient. Results: Intraclass correlation coefficient between centered and decentered CVI1 was 0.71 (95% CI: 0.48–0.85, P value < 0.001). Intraclass correlation coefficient between centered and decentered CVI2 was 0.73 (95% CI: 0.5–0.86, P value < 0.001). The mean difference between centered and decentered directional measurements for CVI1 and CVI2 were 0.5 and 0.8, respectively. Conclusion: There is moderate agreement between CVIs obtained from centered and decentered directional single OCT scans of the same subfoveal area. Studies investigating choroidal vascularity should be standardized by using the same OCT beam direction in all scans.

Short-Term Morphofunctional Changes in Previously Treated Neovascular AMD Eyes Switched to Brolucizumab

“…Therefore, measurements are potentially subject to intraobserver variability. Another limitation is that OCT B-scans performed at the following visits may be slightly misaligned in patients with macular disorders [ 35 ], even with the employment of the OCT follow-up tracking. Even with this limitation, several studies have investigated the CVI in patients with macular disorders.…”

Comparison of the Choroidal Vascularity Index Measurements of Images Acquired With Different Optical Coherence Tomography Scan Scale Types

“…18 In addition, some studies investigating changes in the choroidal structure before and after treatment have found contradictory changes. [19][20][21] In the study of Ersoz et al, 14 CVI measurements taken from OCT scans, obtained according to whether the pupil entry position of the beam is centered or decentered, were compared. Although the authors used the tracking mode of OCT devices, they found moderate agreement between measurements.…”

“…However, the reliability of CVI measurements has been questioned, with some-albeit limited-studies on this subject. 3,14 The Heidelberg optical coherence tomography (OCT) device can display images at the 1:1 mm (mm) and 1:1 pixel (horizontally compressed) scales, where the device catalogue states that measurements should be performed only using the 1:1 mm option to avoid errors when measuring distance in OCT images. In addition, it has been reported that choroidal thickness measurements taken from 1:1 pixel images differ significantly from those taken from 1:1 mm images.…”

“…However, the reliability of CVI measurements has been questioned, with some—albeit limited—studies on this subject. 3,14…”

Henle Fiber Layer Thickness and Area Measurement in Type 2 Diabetes Mellitus With and Without Retinopathy Using a Modified Directional Optical Coherence Tomography Strategy

“…Although the subject remained at the chin rest, the same foveal 30°horizontal line was scanned using follow-up mode with an average of 100 images in a decentered direction by lifting the temporal and then nasal side of the image (temporal and nasal pupil entry position, respectively) as previously described and two additional tilted OCT images were obtained. 8,9,14 To obtain these oblique images, we moved the joystick of the device 1.5 mm to 2 mm from the middle position, where we took the first image, toward the nasal and temporal directions, with the help of a ruler. Henle fiber layer appeared hyperreflective at the nasal side and more hyporeflective than the ONL at the temporal side on tilted OCT images with a temporal pupil entry position and vice versa (Figure 1).…”