Contact lens is a device placed directly on the surface of cornea to correct refractive errors. Wearing contact lens is comfortable during activites, allows wider visual field, and improves aestheticappearance. However, improper use of contact lens may result in mild complications which couldinclude blindness. Those complications can be prevented by understanding and applying correctprinciples of contact lens usage. Prior to contact lens prescription, medical eye examination isimportant to determine if a patient is suitable to use contact lenses. Ocular conditions such as dry eyes, eye infection, cataract, glaucoma, and use of medication that could decrease tears production require special attention. Other conditions that have to be notified are allergy, diabetes mellitus,pregnancy, menopause, chronic respiratory tract infection and immunocompromised condition. Inaddition, poor hygiene and compliance are contraindications for contact lens usage. Learning howto properly handle and maintain contact lens is essential to prevent complications.