Extended wear has been an attractive modality for many contact lens wearers. Despite the associated benefits of convenience and comfort, however, there have been many physiological complications reported for hydrogel extended-wear lenses, and a lesser number for rigid gas-permeable extended-wear lenses. This review describes the physiological as well as the mechanical complications of extended-wear lenses, for both soft lens and rigid lens materials, including etiology, clinical presentation, and management strategies.