Normative Vascular Features on OCT Angiography in Healthy Nepalese Eyes

Abstract

Purpose To establish normative data on morphological characteristics and quantitative parameters of Foveal Avascular Zone (FAZ) as well as their systemic and ocular associations using OCT angiography (OCT-A) in healthy Nepalese subjects. Patients and Methods A prospective, cross-sectional, population-based study recruiting 210 healthy samples (420 eyes) aged 10 to 70 years was conducted. All the samples underwent detailed comprehensive eye examination followed by Optical Coherence Tomography Angiography (OCTA) and Enhanced Depth Imaging performed in each eye using Spectral Domain Optical Coherence Tomography. Foveal avascular zone area and vessel density in superficial and deep retinal plexus and Sub foveal Choroidal Thickness (SFCT) were evaluated. Ocular and systemic associations of these parameters were also studied in a multivariate analysis utilizing linear regression. Results The mean superficial and deep FAZ area was 459.96 ± 124.75 μm (95% confidence interval [CI], 443.08–476.83) and 589.0 ± 141.39 μm (95% CL, 570.77–609.02), respectively. The vessel density in superficial capillary plexus was 54.03 ± 9.34% (95% CL, 53.98–54.11) while the vessel density in deep capillary plexus was 25.91 ± 38% (95% CL, 25.85–25.96). The mean SFCT in this study was 308.89 ± 68.87μm (95% CL, 299.64–318.14 μm). There was no statistically significant inter-eye difference in the FAZ parameters. Myopic eyes had smaller FAZ, lesser vessel density and thinner SFCT. Association was observed between superficial FAZ area and systolic blood pressure, and deep FAZ area and diastolic blood pressure. Conclusion This study reports the normative data on FAZ parameters in healthy Nepalese subjects which can serve as references for interpreting these parameters in different retinal-choroidal diseases.

Mean Amplitude of Diurnal Variation of Sub-Foveal Choroidal Thickness among Adults with Healthy Eyes Visiting Outpatient Department of a Tertiary Eye Care Centre

“…The baseline SFCT in this study was 339.70±29.13 microns, surpassing the previously reported SFCT in two recent Nepalese studies (308.89±68.87 μm and 310.31 ±75.70 μm, respectively). 12 , 13 The baseline SFCT was also higher than that reported in the Indian population (307±79 μm), Spanish population (301.89±80.53 μm), and Chinese population (328.8 μm). 14 - 16 This discrepancy may be attributed to the variation in the age group enrolled; our study exclusively included healthy adults aged between 20-30 years, whereas the aforementioned studies aimed to assess mean SFCT across a broader age range, from pediatric to geriatric populations.…”

“…10,11 The baseline SFCT in this study was 339.70±29.13 microns, surpassing the previously reported SFCT in two recent Nepalese studies (308.89±68.87 μm and 310.31±75.70 μm, respectively). 12,13 The baseline SFCT was also higher than that reported in the Indian population (307±79 μm), Spanish population (301.89±80.53 μm), and Chinese population (328.8 μm). [14][15][16] This discrepancy may be attributed to the variation There are a few limitations in our study.…”

SubFoveal Choroidal Imaging in High Myopic Nepalese Cohort

“…In the two extant studies examining choroidal thickness in healthy Nepalese population [ 26 , 27 ], distinctions in choroidal thickness measurements were observed in Nepalese subjects relative to populations of varying ethnic/racial backgrounds. Therefore, in this study, we evaluated SFCT measurements in high myopic Nepalese subjects and compared it with healthy controls to explore if similar changes in SFCT were evident in high myopic Nepalese subjects as well.…”