During the last few decades, significant technological and medical progress has been achieved in the production and application of contact lenses: from rigid to rigid gas-permeable to soft and soft silicone lenses. Contact lenses belong to a group of quality medical aids that have a number of advantages compared to glasses. These are better quality of vision and a wider field of vision. They also have certain disadvantages or complications. Complications occur more often in people who have risk factors for the development of complications, i.e. appropriate pre-existing conditions that can trigger their development. Risk factors include the type of contact lens used, the presence of deposits and contamination of contact lenses, and the method of maintaining contact lens hygiene. Predisposing user conditions that pose a risk for wearing and developing complications include infrequent blinking, medications, smoking, the schedule of wearing contact lenses, lack of consultation with a doctor, and the existence of contraindications for wearing contact lenses. Non-infectious complications include dry eye, sterile corneal infiltrates, problems with the corneal epithelium, mechanical abrasion of the cornea, hypoxic reactions, toxic and/or immune reactions, superior limbic keratoconjunctivitis, tight lens syndrome, dislocated contact lens, giant papillary conjunctivitis, subconjunctival hemorrhage, endothelial complications and limbal stem cell deficiency. Infectious keratitis is the most significant of the infectious complications. In order to prevent the occurrence of the complications, it is most important to follow the instructions for proper care and storage of contact lenses. If complications occur, timely diagnosis and treatment is important, since the visual consequences can be different, ranging from insignificant to those that prevent sight.