The Effects of Bevacizumab and Ranibizumab on Ocular Pulse Amplitude in Neovascular Age Related Macular Degeneration (AMD)

One concern about repeated intravitreal injections of bevacizumab (Avastin) and ranibizumab (Lucentis) in wet age related macular degeneration, is that in addition to blocking the proteins that triggers the development and proliferation of abnormal vessels in the center of the retina, they may also result in changes in the normal vessels that feeds the outer part of the retina. Small vessels with fenestrations (such as those that feed the outer part of the retina, which are called choriocapillaris) appear to be especially sensitive to this protein (called vascular endothelial growth factor, VEGF) withdrawal. It is estimated that global blood flow in the vascular layer under the retina (called choroid) may be indirectly assessed by measuring the amplitude of the ocular pulsation (the pressure inside the eye change according to the cardiac cycle, similar to the change in blood pressure) which is called Ocular Pulse Amplitude (OPA). The Pascal Dynamic Contour Tonometer (Pascal DCT) is a new tonometer (a device which measures the pressure within the eye) designed to measure intraocular pressure and ocular pulse amplitude. No published study has yet assessed the effect of bevacizumab (Avastin) or ranibizumab (Lucentis) treatment for wet AMD (or on any other retinal disease) on OPA. This is our aim in this pilot study, in which we will measure the pressure within the eye just prior to bevacizumab/Ranibizumab treatment, followed by repeated measurements a week and a month after the treatment. For this purpose, up to 60 patients with wet AMD will be recruited.