vision defects 
Images do not form on the retina, thus resulting in blurry vision; such defects are corrected by eyeglasses, contact lenses or even surgery.
The image of a distant object is formed in front of the retina due to a defect in the light rays’ convergence. This makes distant objects hard to see.
Point where light rays converge to form an image; the brain interprets the retina’s upside-down image as right-side-up.
Corrects myopia by causing light rays emanating from an object to diverge and project an image onto the focus of the retina.