The role of the pH microenvironment in retinal diseases

Measurements and modeling of intraretinal (H)⁺ can provide information about the retinal microenvironment in disease. Here, the concentration of H⁺ in the outer retina was measured to understand the role of H⁺ in diabetic retinopathy, and simulations or H⁺ gradients were performed to understand the possible contributions of changing pH to the pathogenesis or age-related macular degeneration (ARMD). Intraretinal pH profiles were recorded in anesthetized diabetic cats using pH sensitive microelectrodes. During diabetes, there were changes in the inner retinal H⁺ gradient in some areas of the retina. Some pH profiles showed decreased H⁺ production in the outer retina. The pH changes in ARMD were investigated using simulations of a four-layer diffusion model. The effects of variable drusen size and choroidal blood flow (ChBF) were investigated. The pH profiles showed that there was increased H⁺ concentration in the outer retina with the introduction of drusen.