Creasing as a candidate mechanism of foveal pit formation

Creasing is a phenomenon observed in hyperelastic materials and is characterized by sharply localized surface deformations that appear at ~35% compressive strain. The foveal pits of anoles (small iguanian lizards) are funnel-shaped and resemble creases when cut along the central axis. Furthermore, during foveal pit formation the anole eye contracts around 35% along this same axis [1]. We investigate creasing in synthetic retina-like geometries using (i) everted hemispherically capped tubes that extend recent experiments with uncapped tubes [2], and (ii) a vacuum apparatus that allows for curing a small puddle of elastomer in a pre-tensioned elastomer bowl. The latter experiment directly tests a recent hypothesis that a reduction in intraocular pressure drives foveal pit formation, and that an observed localized retinal mounding may also be implicated [1]. Our experimental results include features reminiscent of both foveal pits and visual streaks, and may lead to a better understanding of retinal morphogenesis under both normal and pathological conditions.



[1] A. M. Rasys, et al., Dev. Dyn. 250, 1584 (2021).

[2] X. Liang, F. Tao, & S. Cai, Soft Matter 12, 7726 (2016).