Purpose: To investigate the influence of posterior subcapsular cataract (PSC) on structural optical coherence tomography (OCT) and OCT angiography vessel density (VD) measurements.
Materials and methods: One eye each of 10 consecutive participants with PSC were imaged using the Angiovue/RTvue-XR OCT via undilated pupil, and 30 minutes later via dilated pupil. Peripapillary retinal nerve fiber layer thickness (RNFLT), peripapillary capillaries and all-vessels VD, ganglion cell complex thickness (GCC), parafoveal VD, and the image quality scores were compared, respectively.
Results: PSC grade (mean±SD) was 4.0±0.9, and best-corrected visual acuity was 0.8±0.2. Image quality was high for all eyes and images (baseline median signal strength indices for RNFLT and GCC: 66 and 67.5; image quality scores for peripapillary and parafoveal VD: 7.5 and 6.0) and did not change statistically and clinically significantly for pupil dilation (P≥0.0872). The mean RNFLT and GCC values increased by 1.0 and 1.1 μm, respectively (P≥0.1382; ~1% of the normal values). In contrast, the mean peripapillary all-vessels VD value increased by 1.2% (P=0.0349) and the mean peripapillary capillaries VD value by 1.1% (P=0.0599; ~2 to 2.5% of the normal values, for both parameters). No change in parafoveal VD was seen (0.2%, P=0.8209).
Conclusions: Our results suggest that PSC-related peripapillary VD reduction may falsely suggest glaucoma progression, even when RNFLT is not influenced by PSC. Glaucoma eyes with developing PSC need pupil dilation for peripapillary VD measurements to reduce the PSC-related VD reduction.