A Primer On How Bifocal Contacts Work

Before discussing how bifocal contacts work, it seems prudent to first make clear who exactly needs them, and why they do. Presbyopia is an esoteric yet rather ubiquitous ailment that affects a great many people over the age of 40. Over time the ciliary muscle (responsible for contracting and stretching in order to focus) begins to lose elasticity and thereby is unable to properly move and therefore focus. It is this that results in the need for Bifocal correction. How bifocal contacts work is really rather simple:

Bifocal means 'two focal points' and it is from this that we can derive their functionality. Much like bifocal eyeglasses, bifocal contact lenses are composed of two different powers (otherwise known as prescriptions) on a single lens, allowing for correction of both far and near viewing depending on through which portion of the lens it is viewed. As with the first bifocal glasses, this is based upon the assumption that you usually look down when viewing nearer objects and up when trying to see things farther away. Modern designs, however, are called progressive bifocals because instead of a distinct, easily distinguishable line between the two portions of the lens, they feature a gradual change in prescription across the lens so as to facilitate a smooth transfer between viewing distances as your eye roams around the lens. Exactly how these two powers are placed on the lens varies, and can be done in aspheric, concentric and other designs.

An important aspect of what makes a bifocal lens work effectively is fit, and is vital for the efficacy of bifocal lenses. That and patience, because the onus is on your eyes and brain to become used to the subtle differences in the lens and to properly differentiate how and when to best use each. This can take a great deal of time and persistence. Although how bifocal Contact Lenses work is not that much different in theory to traditional bifocal lenses, the fact that contacts move around the eye, and are almost never in exactly the same place can make it virtually impossible to get consistent vision from a bifocal lens. You may get good distance vision and poor near vision or vice versa.

It is for this reason (and the headaches and nausea that can accompany the 'adjustment period') that the success rate of bifocal contact lenses is not that high. But, with that being said and now that you've been properly edified as to how bifocals work, be sure to browse the linked products to your right to find eye wear solutions that, if nothing else, will fit your wallet.

Shop for: