As we get older our eye can suffer from Presbyopia, this can occur when our eyes are unable to focus incoming light due to the loss and flexibility in our eye muscles. The unfortunate result is that trying to read close-up such as reading a book or newspaper or even trying to use computer screens can become blurred. Bifocal contact lenses add an extra layer of near vision correction to the actually lens give you the power to focus and see object's close-up. There is usually a far-vision layer also. There are three different types of bifocal contact lens designs. 1. Alternating
2. Concentric
3. Simultaneous
In Alternating or translating bifocal lenses, the near and far connective layers of the lens are distinct from each other. The near correction layer is usually placed at the bottom of the lens but if needed can be reversed. The intermediate layer can also be added and changed. In concentric bifocal lenses the near and far layers are arranged in rings, the near vision is in the centre and the far vision layer on the outer ring. If you have small pupils this arrangement can be reversed this would put the far vision layer in the centre and near vision on the outer ring. In Simultaneous bifocal lenses both layers are in the centre of the lens, this may seem strange but your eyes learn to adapt to each correction layer. This of course may take a little time but you're eye care specialist can advice more on this. Some people may find it difficult to get used to bifocal contact lenses, if you have adapted to bifocal, trifocal, or progressive eyeglass lenses, you'll already understand the basics of using translating bifocal contact lenses, in which the distance zone is straight ahead and above center, while the reading zone is lower. With simultaneous designs, your eyes will learn to focus near or far as needed. Whatever your particular lenses design, your eye-care specialised will make sure you understand how to use it. Bifocal contact lenses come in soft and rigid gas permeable (RGP). In general soft contact lenses can become cloudy with protein deposits over time, they have also been known to be easy to tear. Gas permeable contact lenses are more durable and made from a stronger plastic that stays clearer over time. When you have RGP bifocals they last longer but you may need new ones only when your presbyopia progresses so that you need a stronger near vision prescription. |
