1. A method of determining a corneal thickness comprising the steps of: illuminating a cornea by a plurality of stimulator point light sources, capturing an image of the cornea comprising reflected images of the stimulator point light sources, obtaining a model representing an anterior surface of the cornea, constructing a second model representing a posterior surface of the cornea from the image by ray-tracing the reflected images of the stimulator point light sources towards the model representing the anterior surface of the cornea, and determining the corneal thickness from the model representing the anterior surface and the second model representing the posterior surface.