American Board of Ophthalmology (ABO) Practice Exam

Invisible bifocals are commonly referred to as progressive lenses. These lenses are designed to provide a smooth transition between different focal lengths, allowing for clear vision at various distances without the visible lines that characterize traditional bifocal lenses. This functionality makes them a popular choice for individuals who need correction for both near and distance vision.

The term "invisible" relates to the absence of the telltale line that separates the different lens powers in conventional bifocals, which can be seen as a cosmetic issue for many users. Progressive lenses provide a more aesthetically pleasing solution while maintaining the necessary visual correction.

The other options do not capture this dual functionality and design. Vanity lenses, while a term that might suggest aesthetic appeal, do not specifically refer to the type of lens described in the question. Single vision lenses offer correction for only one distance, and bifocal lenses have a visible line separating the two prescriptions, which is not in line with the "invisible" aspect of the product. Therefore, progressive lenses are the correct term for what is commonly known as invisible bifocals.