Distances From Capillaries to Arterioles or Venules Measured Using OCTA and AOSLO

Area of Science:

• Ophthalmology
• Medical Imaging
• Vascular Biology

Background:

• Understanding retinal vasculature is crucial for diagnosing and managing eye diseases.
• Noninvasive imaging techniques are advancing the study of microvascular structures in the retina.

Purpose of the Study:

• To noninvasively investigate the distances between retinal capillaries and larger vessels (arterioles/venules).
• To quantify periarteriole and perivenule capillary-free zones in healthy subjects.
• To explore correlations between these zones and the foveal avascular zone (FAZ).

Main Methods:

• Employed adaptive optics scanning laser ophthalmoscope (AOSLO) and optical coherence tomography angiography (OCTA) for detailed retinal vasculature mapping.
• Quantified capillary-free zone distances in the superficial vascular plexus of 20 healthy subjects.
• Correlated these findings with FAZ parameters and examined a diabetic patient's retinal vasculature.

Main Results:

• Periarteriole capillary-free zones (67.2 ± 25.3 μm) were significantly larger than perivenule zones (42.7 ± 14.4 μm) (P < 0.0001).
• Distance from the foveal center and vessel diameter predicted perivenule zone values.
• Focal enlargements of capillary-free zones were observed in a type 2 diabetic patient.

Conclusions:

• Periarteriole and perivenule capillary-free zones are clearly visualized using OCTA and AOSLO in normal retinas.
• The larger periarteriole zones suggest a role in supporting the retina with oxygen-rich blood from arterioles.
• These findings provide insights into retinal blood flow dynamics and potential alterations in disease states.