Accommodative Behaviors in Multifocal Contact Lenses

Addition lenses are often used to treat a range of eye conditions. Addition lenses are specifically used to help patients who do not have the ability to focus their eyes to see clearly up close. Eye focusing is called accommodation. Addition lenses are easy to prescribe in a pair of glasses and are often called the bifocal portion of the glasses. Addition lenses can be used for adults who have presbyopia (they cannot read up close without the aide of a bifocal) and for patients of all ages who have eye focusing problems (e.g. accommodative insufficiency, accommodative infacility, accommodative dysfunction). Addition powers can also be put into contact lenses. Contact lenses that have addition powers in them are called multifocal contact lenses. These are often marketed for patients that are 40 and over who have presbyopia, and are prescribed to help patients see up close as well as far away in their contact lenses. Multifocal contact lenses are also used in children with nearsightedness because studies have shown that some multifocal designs can slow down the progression of nearsightedness. As stated before, addition lenses can be used to treat eye focusing problems in patients of all ages, before presbyopia. What is unclear is whether the addition power in contact lenses has the same treatment effect as an addition power in a pair of glasses when they are being used to treat eye focusing problems. This study will assess how different kinds of multifocal contact lenses (center distance or center near) will change eye focusing and eye teaming in young adult patients.