Conventional lenses are those which are prescribed for daily wear and you keep the same pair of lenses all year without disposing of them. Theses lenses are generally made to be more durable and are made with materials that last longer than those of disposable lenses.
Disposable lenses are those which can be discarded every 2 weeks, monthly, every 2 months, or quarterly depending upon the lens design and material used. The Food and Drug Administration (FDA) approves each lens for a specific length of wearing time before disposability. These lenses are made with less durable, but usually more breathable, materials than are conventional lenses and thus will not last as long. Proper disposability schedules are necessary to ensure ocular health.