Table 2.

Advantages and limitations of the presented methods.

Methods	Advantages	Limitations
CDI	Commercially available	No volumetric blood flow data
	Non-invasive and rapid method	No information about vessel diameter
	Studies in laboratory animals available	Angle of incidence as common source of error
		Training mandatory to ameliorate reproducibility
CTA	Rapid and reliable method	Potential adverse effects associated with intravenous contrast agents
	Reproducible data on blood vessel morphology and course	Limitation in functional studies
		Radiation exposure
		Limited use in laboratory animals due to small vessel size and affection by general anesthesia
MRI	Non-invasive	Expensive
	High-resolution 3D images with superior soft tissue contrast	Potential adverse effects associated with intravenous contrast agents
	Methods without use of contrast agents available	Exposure to noise, claustrophobia and presence of electronic implants as limiting factors for patients
	No radiation exposure	Limited use in laboratory animals due to small vessel size and affection by general anesthesia
Myography	Investigation of local mechanisms of vascular reactivity in small laboratory animals	Difficult isolation and preparation of retrobulbar vessels
	No affection by general anesthesia in laboratory animals	No longitudinal studies available
	Studies in genetically modified animals available