Abstract
Purpose: :
The Retinal Function Imager (RFI) implements a new, non-invasive diagnostic approach to measuring blood flow velocity. Intravitreal Bevacizumab (Avastin) is widely used for treatment of various retinal conditions. We used the RFI to learn about the drug’s effect on retinal vascular function.
Methods: :
This pilot study includes eleven patients who received intravitreal injection of Avastin (1.25 mg). RFI scans were recorded before injection and 1 and 7 days after injection. Blood flow velocity was quantified for secondary and tertiary branches of arteries and veins. Visual acuity, detailed retinal examination and Ocular Coherence Tomography (OCT) were recorded before the injection and a month after it. Response to the injection was determined by these 3 parameters. All velocity comparisons were done using paired student t-test.
Results: :
Six subjects were diagnosed with choroidal neovascularization (CNV), and five with retinal vein occlusion (RVO). Four of the six AMD CNV patients had good response to the Avastin injection. All vein occlusion patients had a good response to the Avastin injection. The following table describes the velocity changes in these patients compared to baseline:
Conclusions: :
The RFI provides a non-invasive technique to assess hemodynamic responses to intravitreal injection of Avastin, demonstrated for the first time in this pilot study. These changes may be a key to understanding the mechanism underlying this treatment and serve as a marker for desirable treatment optimization.
Keywords: age-related macular degeneration • blood supply • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)