Prognostic MRI biomarkers of treatment efficacy for retinopathy

There is a pressing need for retina-specific imaging biomarkers that robustly measure early (subclinical) changes in physiology, are linked to the histopathology responsible for vision loss, and, importantly, predict treatment efficacy. This review focuses on the following four MRI markers that we have developed and applied in preclinical and clinical settings: preretinal vitreous oxygen level (a steady-state biomarker of inner retinal oxygen tension); leakage of contrast agent into the vitreous (a steady-state biomarker of blood-retinal barrier permeability surface area product); change in preretinal vitreous oxygen tension during a hyperoxic provocation (a functional biomarker of vascular autoregulation); and retinal uptake of systemically administered manganese during a visual task (a functional biomarker of intraretinal ion regulation). We conclude that functional biomarkers are most promising for prognostic evaluation of treatment efficacy earlier in the course of retinopathy than is currently possible.