Macular retinal vascular density and thickness in high myopia patients

Abstract

Objective To measure the macular vascular density (VD) and retinal thickness (RT) of highly myopic patients by optical coherence tomography angiography (OCTA) and analyze their correlation. Methods A total of 110 myopia patients (110 eyes) aged 18~40 years who attended the Ophthalmology Clinic of the First Affiliated Hospital of Chongqing Medical University from September 2020 to September 2021 were included. According to spherical equivalent refraction (SER), they were divided into high myopia (HM) group (SER < -6.00 D, 57 eyes) and control group (-6.00~-0.50 D, 53 eyes). OCTA was performed on all subjects to quantify the retinal thickness and superficial vessel density. The differences in VD and RT were compared between the control group and HM group, and correlation analysis was carried out. Results In general, the vascular length density (VLD) and vascular perfusion density (VPD) in the inner ring were significantly lower in the HM group than the control group (P < 0.05). The perifoveal VLD and VPD had no significant changes. There was no statistically significant difference in the characteristics of foveal avascular zone (FAZ) including area, perimeter and circularity between the 2 groups (P < 0.05). The RT of the macular fovea and perifoveal's superior side of the macular area was decreased in the HM group than the control group (P < 0.05), and there were no significant differences in the thickness of the parafoveal quadrants between the 2 groups. Correlation analysis showed that the VLD and VPD of each subzone of the macula were positively correlated (P < 0.05). The VLD and VPD of the fovea and the perifoveal quadrants were positively correlated with the RT of the corresponding area (P < 0.05), while the VLD and VPD of the inner ring had no significant correlation with the RT. RT of partial quadrants of the inner ring and the overall outer ring were positively correlated with SER (P < 0.05), and negatively correlated with axial length (AL) (P < 0.05). VLD and VPD were roughly positively correlated with SER and negatively correlated with AL (P < 0.05). Conclusion RT and VD in macular area are decreased with increased myopia. Early application of OCTA to detect the changes of retinal structure and blood flow circulation in myopic population is helpful for evaluating and monitoring the progress of myopia.

Keywords

• high myopia
• macular retinal vascular density
• macular retinal thickness