Emmetropia
Emmetropia (em"me*trō"pi*ȧ) , noun
[New Latin, from Greek 'e`mmetros in measure, proportioned, suitable ('en in + me`tron measure) + 'w`ps, 'wpo`s, eye.]
(Medicine) That refractive condition of the eye in which the rays of light are all brought accurately and without undue effort to a focus upon the retina; -- opposed to hypermetropia, myopia, and astigmatism.