Scrabble?! ASTIGMATISM

Definitions of ASTIGMATISM in various dictionaries:

noun - (ophthalmology) impaired eyesight resulting usually from irregular conformation of the cornea

noun - (optics) defect in an optical system in which light rays from a single point fail to converge in a single focal point

A refractive defect of a lens or other optical system that prevents light rays from converging at a single point, resulting in a blurred or imperfect image.

A visual defect in which the unequal curvature of one or more refractive surfaces of the eye, usually the cornea, prevents light rays from focusing clearly at one point on the retina, resulting in blurred vision.