Fig. 4.

Analysis of key geometry parameters of cornea and cornea stroma substitute

(a) Print strategy diagram and the concentric-circle motion trajectory of the extrusion nozzle based on a cornea thickness topological graph, assisted by a computer-aided design program. (b) Light path diagram of the cornea before and after the corneal scaffold implantation. (c) The mathematical model of refraction in a corneal scaffold as a negative meniscus lens. ϕ, diameter; R _a, anterior surface curvature; R _p, posterior surface curvature; L, center distance; T _e, edge thickness; T _c, center thickness; f, focal length of the cornea scaffold