ametropia word block on white

ametropia myopia hyperopia astigmatism refraction vision eye optics lens cornea retina prescription glasses contact lenses nearsightedness farsightedness focus blurry eyeglasses visual acuity refractive error ophthalmology optometrist diagnosis treatment correction surgery lasik photorefractive keratectomy laser optical diopter prism exam cataract intraocular problems optometry health focal point accommodation strain clarity detachment ophthalmologist length care bifocals progressive illusion field depth perception anisometropia corneal shape conjunctiva muscles retinal imaging test squint pupil alignment