Does the Presence of a Disc Hemorrhage Affect OCT-Measured Vessel Density and Retinal Nerve Fiber Layer Thickness?

Abstract

To determine if the presence of disc hemorrhage (DH) causes any artifactual change in peripapillary vessel density (VD) and retinal nerve fiber layer (RNFL) thickness as measured by OCT. Cohort study. Glaucoma patients having a single peripapillary DH. Fifteen glaucoma patients having a single peripapillary DH underwent OCT and OCT angiography. Patients were reviewed every 2 months and scans were repeated on disappearance of the DH. Peripapillary VD and RNFL thickness were evaluated at these 2 time points in the DH sector to determine whether the presence of a DH affects these measurements. The mirror-image sector (e.g., superotemporal sector if DH is inferotemporal) was used as a control. Statistical analysis was carried out using the paired t test. Additionally, the analysis of covariance test was used to determine if there was any difference in the measurements between the visits after controlling for signal strength index (SSI). Peripapillary VD and RNFL thickness were measured in the presence of a DH, and then after DH resolution. The mean ± standard deviation (SD) interval between scans was 4.0±0.4 months. The inferotemporal sector was the most common site of DH (66.6%). The mean ± SD intraocular pressure was reduced medically from 16.1±4.7 mmHg at the time of DH to 13.4±4.2 mmHg at the time of DH resolution (P= 0.001). The mean ± SD VD in the DH sector was 52.5±9.7% at the time of DH and 51.1±8.7% on DH resolution (P= 0.30). The mean ± SD RNFL thickness in the DH quadrant was 91±20 μm in the presence of DH and 92±21 μm after DH resolution (P= 0.26). There was no significant difference between the mean VD or the mean RNFL thickness in the DH and control quadrants at these 2 time points after controlling for change in SSI (P > 0.05). The presence of a DH does not artifactually alter the VD or RNFL thickness measurements. Therefore, OCT scans obtained in the presence of a DH may be included in series used for studying progression.