Unilateral Keratoconus after Chronic Eye Rubbing by the Nondominant Hand

INTRODUCTION: To report the development of unilateral keratoconus in a healthy male after persistent unilateral eye rubbing by the nondominant hand which was not needed for professional activities. METHODS: Observational case report. RESULTS: A 60-year-old male was first seen in our clinic due to decreased vision in his left eye. Slit-lamp biomicroscopy of the left eye revealed Vogt's striae, stromal thinning, and a stromal scar. Corneal topography showed a stage 4 keratoconus. Clinical examination and corneal topography of the right eye were normal. Medical history revealed a habit of chronic eye rubbing only in the left eye because of the right hand being occupied for professional needs. During follow-up of 5 years, Scheimpflug images of the right eye stayed normal while the left eye showed a stable cone. DISCUSSION: This case report supports the hypothesis of mechanical fatigue of the cornea due to repetitive shear stress on the surface caused by eye-rubbing.