refractive errors eyeball: hyperopia, myopia, astigmatism.

anterior artery astigmatism blurred central chamber choroid ciliary cornea correction defect diopters disc errors eye eyeball eyesight farsightedness focal focus fovea hyperopia intraocular iris lens longsighted longsightedness myopia nearsightedness nerve ophthalmology optic optical optometrist optometry point pupil refraction refractive retina retinal sclera shortsighted sight sightedness spot vein vision vitreous zonules