Replicating foveal pit formation and evolution in a synthetic eye

Foveal pits, a part of the macula structure within the vertebrate eye, form during eye development in many species and contribute to high acuity vision. In some species, foveal pits are reminiscent of hyperelastic creases due to (i) their cusped surface profiles, (ii) their onset strain, and (iii) evidence of retinal compression [1-2]. Prior work in our lab set out to explore this possible relationship with a synthetic experiment that tests a physics-based hypothesis of foveal pit formation [2]. Here, we build on this experiment by implementing pressure control that facilitates study of post-onset evolution of creases in the synthetic eye. Our preliminary results indicate that creases can elongate over time at constant intraocular pressure, and resemble elongated foveal pits such as seen in some bird species [3]. We also explore experimental parameters such as material stiffnesses, anisotropies, and thicknesses that lead to realistic pit sizes, while also reproducing dimensionless quantities measured in developing eyes (e.g., the ratio of intraocular pressure to retinal stiffness). This experimental framework will ultimately yield a better understanding of the biomechanics relevant to normal and pathological eye development.

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

[2] Rasys, A. M., et al., BioEssays, 2300054 (2023).

[3] Mitkus, M., et. al., J Exp Biol., 219(21), 3329-3338 (2016).