FIGURE 2:

Retina dissection, labelling and sample analysis. (a) Each eye was hemisected around the edges of the cornea. The retinas were extracted and incised into quadrants for mounting. (b) The known density variance in blue cones comparing dorsal and ventral retina was used to consistently maintain the retina’s orientation when generating density profiles. (c) OFF-bipolar cell (BC) populations were each labelled with immunohistochemical markers. (d) Each retina was then sub-divided into ~24 regions of interests, comprising of ~6 sub-fields per respective quadrant. Each field has a corresponding relative cartesian coordinate, all using a reference origin at the optic nerve. Each field size used for approximating densities were ~ 300 μm × ~400 μm in size. (e) Image acquisition was taken in a volumetric fashion, each z-stack encompassing the OPL, INL and IPL with step sizes ranging between 0.9–1.2 μm. Each volume was assessed manually by looking at unique features of each respective cell type to verify accurate counting. (f) For each field’s volume, cell counts were saved as series of individual coordinates which underwent Voronoi tessellation to analyse spatial heterogeneity.