Early progressive lenses were relatively crude designs but modern sophisticated progressive lenses have gained greater patient acceptance and include special designs to cater to many separate types of wearer application: for example progressive addition lenses may be designed with distance to intermediate or intermediate to near prescriptions specifically for use as an occupational lens, or to offer enlarged near and intermediate view areas.
Progressive lenses require careful placement relative to the wearer’s pupil centre for a distance-viewing reference position. Incorrect specification of the fitting location can cause problems for the wearer including (depending on the design of the lens) narrow fields of view, clear vision in one eye only, on-axis blur, and the need to alter the natural head position in order to see clearly.
All progressive lenses are not the same. They differ in price, depending on brand, size and function. Progressive lenses must fit precisely. Even with a perfect fit, however, many people have trouble adjusting to progressive lenses.