Identifying characteristic features of the retinal and choroidal vasculature in choroideremia using optical coherence tomography angiography.

PurposeUsing optical coherence tomography angiography (OCTA) to investigate the area with flow in the superficial retinal vessel network (SVRN) and choriocapillaris (CC) layer among male subjects with choroideremia (CHM), female carriers, and normal controls to identify vascular changes.Patients and methodsImages of SRVN and CC layer were acquired in 9 affected males, 5 female carriers, and 14 age- and gender-matched controls using the Angiovue software of the RTVue XR Avanti.ResultsThe mean age was 33 years for affected male CHM patients (median 30 years), 46 years for female carriers (median 53 years), and 39 years for controls (median 38.5). Mean SRVN area±SD in subjects with CHM was 12.93±2.06 mm2, in carrier subjects 15.36±0.60 mm2, and in controls 15.30±1.35 mm2 (P<0.01). The mean CC area±SD with flow was 6.97±5.26 mm2 in CHM subjects, 21.65±0.17 mm2 in carriers and 21.36±0.76 mm2 in controls (P<0.01). SRVN and CC area with flow showed a negative correlation in CHM subjects with the age (r=-0.86; P<0.003 and r=-0.77; P<0.01, respectively). CC area with flow had a positive correlation with SRVN (r=0.83, P<0.001). Overall, visual acuity had a negative correlation with SRVN and CC area with flow (r=-0.67, P<0.001 and r=-0.57, P<0.002, respectively). CONCLUSIONS: This is the first study to highlight changes in the SRVN in CHM subjects. OCTA detected a reduced area with flow in both retinal and choroidal circulations, and may be a useful tool for monitoring natural history and disease progression in forthcoming clinical trials.

Reconstructing foveal pit morphology from optical coherence tomography imaging.

AIM: The aim of this study was to describe an automated method for extracting quantitative measures of foveal morphology from optical coherence tomography (OCT) images of the human retina. METHODS: We performed a methodological study and retrospective investigation of selected cases. Sixty-five human subjects were included: 61 healthy subjects and four female carriers of blue-cone monochromacy (BCM). Thickness data from B-scans traversing the foveal pit were fitted to a mathematical model designed to capture the contour of the foveal surface. From this model, various metrics of foveal morphology were extracted (pit depth, diameter and slope). RESULTS: Mathematical descriptions of foveal morphology enabled quantitative and objective evaluation of foveal dimensions from archived OCT data sets. We found a large variation in all aspects of the foveal pit (depth, diameter and slope). In myopes and BCM carriers, foveal pits were slightly less deep and had a more shallow slope, although these differences were not significant. CONCLUSIONS: Offline analysis of OCT data sets enables quantitative assessment of foveal morphology. The algorithm works on the Stratus and Cirrus macular thickness protocols, as well as the Spectralis and Bioptigen radial-line scan protocols, and can be objectively applied to existing data sets. These metrics will be useful in following changes associated with diseases such as retinopathy of prematurity and high myopia, as well as in studying normal postnatal development of the human fovea.