noun Ophthalmology.
- faulty refraction of light rays by the eye, as in astigmatism or myopia.
noun
- loss of ability to focus images on the retina, caused by an imperfection in the refractive function of the eye
n.
- An eye abnormality, such as nearsightedness, farsightedness, or astigmatism, resulting from faulty refractive ability of the eye.