Evaluation of retinal vessel quantity within individual retinal structural layers using optical coherence tomography...

Area of Science:

• Ophthalmology
• Medical Imaging
• Retinal Imaging

Background:

• Optical coherence tomography angiography (OCTA) is a key imaging modality for visualizing retinal vasculature.
• Understanding retinal vessel distribution across different structural layers is crucial for diagnosing and monitoring various eye conditions.

Purpose of the Study:

• To quantify retinal vessel density within distinct retinal structural layers using OCTA.
• To investigate the regional variations in retinal vessel quantity across different retinal layers.

Main Methods:

• Utilized Spectralis OCT2 for OCTA imaging in 22 normal eyes.
• Acquired 15x15 degree and two 15x5 degree OCTA scans, analyzing vessel quantity across retinal layers before and after projection artifact removal (PAR).
• Correlated retinal vessel quantity with retinal layer thickness using Spearman correlation.

Main Results:

• Retinal vessel quantity varied significantly by layer and region, with the highest parafoveal density in the inner plexiform layer (IPL) before PAR.
• Nerve fiber layer (NFL) vessels were highest nasally and decreased towards the fovea.
• PAR reduced IPL vessel quantity but had minimal impact on other layers; vessel quantity moderately correlated with retinal layer thickness.

Conclusions:

• Retinal vessel quantity exhibits significant inter-layer and regional variability.
• Projection artifacts can substantially alter vessel quantity measurements, particularly in the IPL.
• These findings highlight the importance of considering layer-specific and regional variations and the impact of artifacts in OCTA analysis.