The Macular Choriocapillaris Flow in Glaucoma and Within-Day Fluctuations: An Optical Coherence Tomography Angiography Study

Abstract

PURPOSE.To assess quantitatively the choriocapillaris (CC) perfusion area in the macular area of healthy eyes, eyes with primary open-angle glaucoma, and eyes with ocular hypertension using optical coherence tomography angiography (OCTA). METHODS.A consecutive series of healthy individuals and patients with glaucoma and ocular hypertension were recruited prospectively in this single-center, cross-sectional study based in Milan, Italy. OCTA was performed in the morning and evening, along with a complete ophthalmologic examination. Macular superficial capillary plexus vessel density (SCP-VD) and the thicknesses of the retina and ganglion cell complex (GCC), as well as their fluctuations, were investigated. RESULTS.Thirty-nine eyes from 24 individuals with glaucoma (mean age = 58.79 ± 6 years), 43 eyes from 27 individuals with ocular hypertension (59.19 ± 6 years), and 54 eyes from 35 controls (58.27 ± 6 years) were enrolled. The mean CC perfusion area values were not significantly different among the three groups in the morning or evening (P ≥ 0.47). In contrast, SCP-VD, retinal thickness, and GCC thickness were statistically different among the groups (P ≤ 0.016), except for the foveal SCP-VD (P ≥ 0.19) and the evening foveal thickness (P = 0.57). Diurnal changes in the CC perfusion area, SCP-VD, retinal thickness, and GCC thickness were not statistically significant (P ≥ 0.16). Systemic hypertension, sex, age, axial length, and diurnal changes in intraocular pressure were not significantly associated with morning or evening measurements, or with diurnal fluctuations (P ≥ 0.07). CONCLUSIONS.The macular CC flow perfusion area appears unaffected in eyes with primary open-angle glaucoma. No significant diurnal changes were observed in any of the parameters investigated.

Choriocapillaris Flow Deficits in Normal Chinese Imaged by Swept-Source Optical Coherence Tomographic Angiography

“…Third, the measurements were taken once and did not reflect the potential diurnal or other changes in the CC FD%. Interestingly, Milani and colleagues 67 did not find differences in choroidal perfusion measured in the morning or at night. Fourth, since our study had a cross-sectional design, causal relationships between the CC FD% and other factors could not be explored.…”

Changes in Retinal Optical Coherence Tomography Angiography Indexes Over 24 Hours

“…A small number of studies evaluated variations in deep retinal layer OCT-A indexes between 8 AM to 8 PM among healthy adults and reported them to be stable throughout the day. 8 , 10 , 11 , 15 Blood flow in the deep retinal layer might be expected to increase at night, since it is nearest to the photoreceptors layer and supplies for its increased metabolic demands in the dark. Nesper et al 61 found a significant transient increase in superficial retinal layer and decrease in deep retinal layer perfusion density during the transition from dark to light.…”

Vascular biomarkers from optical coherence tomography angiography and glaucoma: where do we stand in 2021?

“…In OAG patients, there was a significant decrease in the vessel density in both the parafoveal and perifoveal capillary layers compared with healthy controls, demonstrating a correlation between vessel density loss and increased severity of disease (Lu et al, 2020). Milani et al (2021) compared healthy controls, ocular hypertension patients and OAG. Milani et al (2021) found a significant decrease in whole-vessel density and parafoveal vessel density in the macular superficial capillary plexus in OAG compared with ocular hypertension patients and normal controls.…”

“…In the macula, decreases in vessel density in glaucomatous eyes were seen in a number of capillary layers including the superficial vascular complex, deep retinal capillary layer and whole retina (Choi et al., 2017; Takusagawa et al., 2017; Chao et al., 2019; Milani et al., 2021). A decrease in flow density was also demonstrated by Kromer in both the superficial and deep capillary layers in the macula as a whole, as well as the parafoveal, perifoveal and nasal regions specifically (Kromer et al., 2019).…”

“…Milani et al (2021) compared healthy controls, ocular hypertension patients and OAG. Milani et al (2021) found a significant decrease in whole-vessel density and parafoveal vessel density in the macular superficial capillary plexus in OAG compared with ocular hypertension patients and normal controls. This decrease in vessel density was measured both in the morning and in the evening demonstrating a consistent decrease in vessel density without diurnal variation (Milani et al, 2021).…”