Contact lenses are very light and thin, made of plastic, placed on the cornea or cornea and sclera. Contact lenses achieve better visual acuity. There is no spherical or chromatic aberration as with high diopter glasses. Because contact lenses follow the eye, vision is equally sharp in all directions as opposed to corrective glasses. From diagnostics we apply keratometry, fitting and fluorescence test. There are three types of contact lenses with respect to the part of the eye that covers, hard, gas permeable and soft lenses. Hard contact lenses are made of PMMA (polymethylmethacrylate), are oxygen impermeable and hydrophobic. They are used very rarely, but their absolute indication is keratoconus. Rigid gas permeable (RGP) lenses are more tolerant and comfortable than PMMA lenses. They are oxygen permeable, making them much more convenient for the patient. They are used for severe astigmatism. Soft lenses are made of various polymers, most commonly hydroxyethyl methacrylate. They are prescribed to patients who do not tolerate hard lenses, in nystagmus, and in patients where rapid adaptation is required. Contraindications to wearing contact lenses are bacteria or viral eye infections. The main clinical forms of eye infections conjunctivitis are localization (66.7% of all patients with inflammatory eye diseases) and blepharitis (23.3%), rarely seen keratitis. Complications of wearing contact lenses are blockage of oxygen supply to the eyes, dry eyes, irritation, decreased corneal reflex, corneal abrasion, conjunctivitis, ptosis, and corneal ulcer.