Age related macular degeneration (AMD) is the major cause of irreversible blindness in elderly patients worldwide. The pathogenesis of this disease has been investigated from genetic,1histological,2 and haemodynamic perspectives.3-6 AMD is classified as non-exudative—the dry type, or exudative neovascular—the wet type.7 8Choroidal neovascularisation (CNV) in the macula causes severe visual impairment in AMD. Several angiogenic factors (vascular endothelial growth factor (VEGF) and basic fibroblast growth factor), which are induced by hypoxia and ischaemia, may play a part in the development of CNV.9-11 Choroidal haemodynamics are important for CNV development in AMD.

Chen and colleagues report abnormal choroidal blood flow in asymmetric exudative AMD by measuring pulsatile ocular blood flow (POBF) using an OBF tonometer in 37 patients with asymmetric exudative AMD in this issue of the BJO (p 1411). Their results demonstrated that POBF was significantly higher in eyes with CNV than in the contralateral eyes with drusen. Eyes with disciform scars had lower POBF than the contralateral eyes with drusen. …