Choriocapillaris Vascular Density Changes: Healthy vs. Advanced Exudative Age-Related Macular Degeneration Previously Treated with Multiple Anti-VEGF Intravitreal Injections

Atrophy of retinal vessels in neovascular age-related macular degeneration following long-term treatment with 20 intravitreal anti-VEGF injections

BACKGROUND

The study aimed to evaluate the changes in retinal vascular density in exudative age-related macular degeneration (AMD) after long-term anti-VEGF treatment using optical coherence tomography angiography (OCT-A), and to compare these changes with the vascular density in AMD treated for one year and healthy eyes.

METHODS

In our cross-sectional study OCT-A was performed on 60 eyes of 60 patients. Group AMD 20 × consisted of patients receiving long-term (minimum 20 injections) aflibercept therapy (n = 17), and Group AMD one year consisted of patients treated for one year with a treat & extend protocol (n = 25). The vascular density values obtained with OCT-A were compared with an age-matched control group of 18 healthy eyes. We examined the central retinal thickness (CRT), the vascular density of the fovea and parafovea in the superficial and deep retinal plexus, and evaluated the extent of the non-flow area and the foveal avascular zone (FAZ) on a 3 × 3 mm macular region. Kruskal-Wallis test was performed for statistical analysis.

RESULTS

In Group AMD 20x, the vascular density of superficial retinal plexus in the fovea (p = 0.0022) and parafovea (p < 0.0001) was significantly lower compared to Group one year and control group. In the deep retinal plexus, vascular density in the fovea (p = 0.0033) was significantly lower in both AMD groups compared to the control group, with no difference in the parafoveal region (p = 0.0774). The extent of non-flow area (p = 0.0003) and FAZ (p = 0.0008) were significantly larger in both AMD groups compared to the control group. There was a significant difference in CRT between those treated for one year and control eyes (p = 0.0036).

CONCLUSIONS

In our study, we demonstrated that macular vessel density was lower in the foveal area in the superficial retinal plexus in AMD patients after one year and long-term anti-VEGF treatment. These vascular density changes were absent in the parafoveal and whole areas of the deep retinal plexus. Our results indicate that long-term anti-VEGF treatment reduces the vascular density of the superficial retinal plexus to a greater extent compared to the deep retinal plexus.

Correlation analysis between foveal avascular zone and near peripheral retinal hypoperfusion in multiple sclerosis: a wide field optical coherence tomography angiography study

The identification of non-invasive biomarkers to investigate and monitor retinal structural and vascular changes in multiple sclerosis (MS) represents an interesting source of debate. Until now optical coherence tomography angiography (OCTA) evaluated the foveal avascular zone (FAZ) and areas of retinal non-perfusion only in the macular region in MS patients. It could be interesting to identify possible biomarkers, useful in assessing the ischemic areas also in the near peripheral retina, since FAZ enlargement and the areas of peripheral retinal non-perfusions share common pathogenic processes. In this cross-sectional study, we investigated the correlation between the FAZ area and retinal vessel density (VD) in the near peripheral retina by new wide-field optical coherence tomography angiography (OCTA) in patients affected by relapsing-remitting multiple sclerosis (RR-MS). Moreover, we compared the FAZ area and the VD of superficial and deep capillary plexuses in the fovea region and in the near peripheral retina (6.4 × 6.4 mm) between RR-MS patients and healthy controls by means of a Solix full-range OCTA. Last, we also detected the changes in structural OCT parameters (ganglion cell complex and retinal nerve fiber layer). Thirty-three eyes of 33 RR-MS patients and 35 eyes of 35 healthy controls were enrolled. RR-MS patients showed a lower VD in the superficial capillary plexus and a significant increase in the FAZ area compared with controls. The deep capillary plexus revealed a reduced VD although not statistically significant in patients with respect to controls. In the patients' group, the FAZ area showed significantly negative correlations with VD of superficial capillary plexuses in the foveal and whole region, while the FAZ area did not negatively correlate with the VD of the deep capillary plexus. The significant correlations among OCTA parameters could demonstrate the FAZ area as a possible biomarker for assessing the perfusion status in the near peripheral retina, useful in RR-MS management. These findings could confirm the role of vascular dysfunction in the pathogenetic mechanisms of MS.

OCT angiography analysis of choriocapillaris vascular density in different stages of age-related macular degeneration

Objectives

To analyze the choriocapillaris vessel density (CVD) of eyes at different stages of Age-related Macular Degeneration (AMD) with Optical Coherence Tomography Angiography (OCTA).

Methods

This is a prospective observational cross-sectional study on 21 age-matched healthy eyes and 84 eyes with AMD (i.e., early AMD, late AMD, Geographic Atrophy [GA], and disciform scar AMD). OCTA was used to automatically measure the CVD (%), on both the whole macula and the foveal area, in a layer going from 9 µm above to 30 µm below the Bruch's membrane. Furthermore, in the GA subgroup, the extension of the Ellipsoid Zone (EZ) interruption and the area of macular chorio-retinal atrophy was analyzed.

Results

Macular CVD was significantly lower in the GA, late AMD and disciform scar AMD-subgroups compared to controls (respectively, p=0.0052; p<0.0001; p=0.0003), whereas it did not significantly vary in the early AMD group (p=0.86). A significant difference between the early AMD and both the late AMD and the disciform scar AMD subgroups was also found (p=0.0009 and 0.0095, respectively). When comparing the foveal CVD of healthy and AMD eyes, a significant difference was found with every AMD subgroup (early AMD, p=0.011; GA, p<0.0001; late AMD, p<0.0001; disciform scar AMD, p<0.0001). Furthermore, in the GA subgroup, the CVD had an inverse correlation with both the extension of the EZ-interruption (p=0.012) and with the calculated chorio-retinal atrophic area (p=0.009).

Conclusions

OCTA could play a crucial role in the categorization of AMD, allowing for the evaluation of gradual flow impairment at different stages of the disease. Moreover, the detection of a decreased macular and foveal CVD may shed light on the pathogenesis of AMD.