Five cardinal features of keratoconus are as follows: Manson's sign that is a distortion of lower lid margin caused by bulged cornea when a patient looks in downward gaze Folds and ruptures in des membrane of the cornea Visible or enlarged corneal nerves Fleisher’s rind that is a brownish ring of hemosiderin at the base of a cone VOGT striae the striae are present in post corneal stroma which disappears on pressure