Integrated multimodal assessment of retinal oxygenation, hemodynamics, and neurovisual function in retinal vein...

This study aimed to characterize retinal hemodynamics, oxygenation and oxygen kinetics, and neurovisual alterations in retinal vein occlusion (RVO) using an integrated ocular multimodal imaging system.

This cross-sectional study included 105 eyes with branch retinal vein occlusion (BRVO), central retinal vein occlusion (CRVO), or no retinal disease. RVO eyes were either untreated or previously treated with anti-vascular endothelial growth factor. The system simultaneously assessed retinal oxygenation and oxygen kinetics, vascular structure, blood flow and pulsatility, pupillary light reflex (PLR), and smooth pursuit eye movements (SPEM).

The study included untreated CRVO (n = 12), previously treated CRVO (n = 23), untreated BRVO (n = 14), previously treated BRVO (n = 32), and healthy controls (n = 24). At the nominal P < 0.05 level, arterial oxygen saturation was lower in untreated BRVO eyes than in healthy controls (raw P = 0.0315) and higher in previously treated than in untreated BRVO eyes (raw P = 0.0456). Venous oxygen saturation was lower in untreated CRVO and both BRVO groups (raw P = 0.0046-0.0190), and venous oxygen concentration was lower in both BRVO groups (raw P = 0.0060-0.0265). The arteriovenous differences in oxygen saturation and concentration were higher in previously treated CRVO and BRVO eyes (raw P = 0.0090-0.0339), and oxygen extraction fraction was higher in untreated CRVO and previously treated BRVO eyes (raw P = 0.0114-0.0259). Flow acceleration index was higher in both previously treated groups (raw P = 0.0368 and 0.0443). Arterial external diameter (ED^a) was smaller in previously treated CRVO and both BRVO groups (raw P ranging from < 0.0001 to 0.0095). PLR abnormalities were most evident in CRVO, whereas SPEM velocity and velocity gain were higher in all four RVO groups (raw P = 0.0018-0.0175). ED^a, PLR, and SPEM differences remained significant after false-discovery-rate correction (q < 0.05). Exploratory analyses of the relationships between vascular, hemodynamic, oxygenation and oxygen kinetics, and neurovisual measurements identified associations of blood flow velocity, retinal blood flow, and arterial external diameter with PLR and SPEM parameters.

Integrated multimodal assessment identified distinct patterns of vascular, oxygenation and oxygen-kinetic, and neurovisual abnormalities across RVO groups. PLR abnormalities were mainly observed in CRVO. SPEM abnormalities occurred in both CRVO and BRVO. These findings provide a basis for selecting candidate measurements for future prospective studies of disease progression, treatment-related changes, and visual outcomes using the same platform.