VEGFA and age-related macular degeneration: Pegaptanib’s tertiary structure provides isoform-selective targeting of VEGF, binding the extracellular isoform most relevant to AMD progression (VEGF-165) while sparing other biologically active isoforms important in heathy function (VEGF-121) (Ruckman et al., 1998; Lee et al., 2005; Kim, 2007).