hand-held glasses, view of the snellen chart. blue background

acuity astigmatism background bifocal black chart closeup concept conceptual corrective crystal distance exam examination eye eyeglasses eyesight eyestrain farsightedness frame glasses horn lens longsightedness looking medicine myopia myopic nearsightedness object oculist ophthalmologist ophthalmology optical optician optics optotypes plastic read rimmed see seniors short sight snellen spectacles test vision visual white