A remarkable degree of conformance between the visual streak of the Mongolian gerbil and the human central retina

Abstract

The Mongolian gerbil (MG) is a day-active rodent that lives in desert-like environments and thus very much relies on vision. To allow for a particularly exact view of the horizon, the region of highest visual acuity, the visual streak (VS), forms a horizontal band across the retina between the projection areas of the sky and the ground. Here, we assessed the retinal basis of this specialized region and compared the findings to the human central high-acuity region culminating in the macula. We found an increased density of cones, elongated photoreceptor outer segments (OSs) and a minimization of intersecting surface vessels to improve quality of vision, all of which is analogous to the human macula. Stunningly, also the area of retinal pigment epithelium (RPE) cells was significantly smaller in the VS region than in the periphery, again similar to what is found in the human macula. Our data therefore suggest that the remarkable degree of conformance between the VS of the MG and the human macula renders the MG a promising rodent, non-primate model of the central human retina.