Keratoconus causes a reduction in the optical quality of the eye as a result of corneal distortion, corneal scarring and higher-order aberrations. The correction of these optical aberrations would significantly improve the visual performance of keratoconic eyes. However the first step would be to measure the optical flaws in keratoconus accurately, which in itself presents a challenge. This paper will attempt to explain the optical aberrations typically found in keratoconic eyes, and will also review the progress made in attempting to correct them using soft contact lenses.