Table 1: Elements of normal visual functioning and their interactions. For brevity, the term “Eye” implies also “Vision.” Abnormalities in any one of these functions can lead to imbalances and compromise healthy vision

Brain-Eye-Vascular Interactions
E2B		B2V
Phototransduction		Autonomic innervation
Neural processing and transmission		Acute and chronic stress
Melatonin/circadian rhythms		Stress hormones
Thermoregulation		Endothelin, cortisol
		Pressure regulation
B2E
Neural processing		V2B
Eye and head muscle control		Blood supply
Iris contraction		Intracranial pressure
Intracranial pressure		regulation
Visual analysis/		Microsaccade-heartbeat
interpretation		coupling
• Vigilance
• Focal/global attention		E2V
• Visual memory		IOP
• Motivation		Perfusion pressure
• Expectation/cognition
• Emotions/stress		V2E
• Stressors		Blood supply
• Atmospheric pressure		Vascular dysregulation

E: Eye and vision; B: Brain; V: Vascularity