Monofocal lenses are a type of lens used in eyeglasses or contact lenses that have a single prescription strength. They are designed to correct vision at one specific distance, which can be for seeing far away or up close. These lenses are commonly used by people with myopia (nearsightedness) or hyperopia (farsightedness). In the context of cataract surgery, monofocal lenses can be implanted to replace the cloudy natural lens of the eye. Patients typically choose a lens that best suits their primary vision needs, such as distance vision, while they may still require reading glasses for close-up tasks.