As time goes on and we get older we try harder and harder to maintain our youthful appearance. One inevitable fact that must be faced by all is the need for reading glasses. As we get older the lens inside our eye that can increase or decrease its refractive power allowing the eye to focus on objects both far and near loses some of its elasticity making the viewing of near objects difficult. This condition is called Presbyopia and becomes noticeable around middle age. Most people faced with this condition cringe at the idea of wearing bifocals or granny style reading glasses. Fortunately these are only two of the many options available.
Contact Lenses for Presbyopes
Multi-focal lenses are the most common option employed by eye care professionals for the correction of presbyopia. As its name implies a multi-focal lens has more than one focal length, one for reading the other for distance vision some even have a third focal length for intermediate vision such as a tri-focal or progressive lens. Two factors of this lens that many wearers find undesirable are the obvious line and something called image jump. Viewing through the distance area and changing to view through the reading can cause the image jump into the reading segment. So why do some people wear bi-focals and other tri-focals? Is there an advantage of one over the other? Well this depends on the person. Often people with advanced presbyopia need that extra help to view images at an intermediate viewing distance, that is not quite near not quite far. Others who?s visual requirements necessitate the need for intermediate vision such as certain hobbies and work tasks. For those who wish to be a little more discrete about there visual need there is the progressive lens.
The progressive lens was introduced over forty years ago and since has become on of the most intricate and advanced lens on the market. It incorporates a top section for distance an intermediate channel that transitions into the reading area. This provides the wearer with continuous vision. Lens designs vary in corridor length, width and depth as well as reading size and placement. A draw back of the progressive lens is the limited reading area and the slight blurriness that is located at the lower nasal and temporal periphery of the lens. These zones are called the blending zones. These are the areas that combine the many curvatures found on a progressive lens. The blending zones are the unused areas of the lens but these areas can cause a ?swimming? feeling for the wearer. Many designs to day are created with a softer design. A hard design has a high concentration of blur in these zones were as softer design spread this out to decrease the intensity. Keep in mind that the first time you put these lenses on it can be a bit frustrating. You must learn to move your head to look at an object as opposed to moving ones eyes. Moving the eyes can cause the wearer to look through the reading section when the situation requires viewing through the distance area. Keep in mind that it can take up to a week to fully adjust to this lens. Even contact wearers have options.
Various styles of bifocal contact lenses are currently on the market with varying designs, one design resembles a lined bi-focal lens which is called a translating or alternating lens. This design is only available in hard or rigid lenses. Hard lenses are designed to ?float? on the tear film that covers the cornea. This allows for free exchange of tears that is es