Bifocal and Multifocal Contact Lenses for the Presbyopic
After age 40, the single pair of glasses or contact lenses you previously wore may no longer give you clear vision at all distances. This is caused by presbyopia, a vision problem which affects us beginning in middle age and reduces our ability to see at all distances. Many vision correction options are available, such as presbyopia surgery, eyeglasses and multi-focal or bifocal contact lenses.
The main sign that you’re developing presbyopia is that you need to hold newspapers or other reading material farther from your eyes in order to see them clearly.
What’s the difference between Bifocal and Multifocal Contact Lenses?
Bifocal contact lenses are designed to provide good vision to people who have a condition called presbyopia. Bifocal contact lenses come in both soft materials and rigid gas permeable (GP) materials. Most bifocal contact lenses can be worn on a disposable basis with the convenience of throwing the lenses out at specified intervals (Monthly, weekly and even daily, in some cases) and replacing them with new lenses.
Bifocal contacts lenses have two prescriptions in the same lens. Multifocal contact lenses have a range of powers (similar to progressive spectacle lenses) in each lens.
Unlike Bifocal contact lenses, multifocal contact lens designs work more like progressive eyeglass lenses, where the different prescriptive powers are blended across the lens.
How Multifocal Contact Lenses Work
Bifocal and multifocal contact lenses work in several different ways, depending on the design of the lens. The designs fall into two basic groups; Bifocal contact lenses use “Alternating vision” (translating) lenses, named because your pupil alternates between the two powers, as your gaze shifts upward or downward. And Multifocal contact lenses use simultaneous vision, which require your eye to be looking through both distance and near powers at the same time. Both are very effective.