Assertion: astigmatism's cornea | /r/HasAspect | perfect curve
Facets:
value: in order to bend light
type: PURPOSE
Source sentences:
text: The cornea needs to have a perfect curve in order to bend (refract) light properly as it goes into the eye.
text: It occurs when the corneas in your eyes (the clear lenses on the very front) have a non-perfect shape.