The most basic form of a spectacle or contact lens is the single vision lens, which is made to a single prescription distributed throughout the entire lens to correct a particular eyesight problem. They are suitable for all situations such as driving, working or reading.
These lenses can be used in the correction of short sightedness, long sightedness, astigmatism and combinations of these conditions. Normally, people who wear corrective lenses under the age of 40 wear this type of lens.
The majority of aspheric lenses on the market today are also high index lenses. The combination of an aspheric design with high-index lens materials generate a lens that is markedly slimmer, thinner and lighter than standard lenses. They enable a person with a strong prescription to wear a greater selection of frames without the worry that the lenses are too thick.
Bifocal lenses are made up of two elements, each with a different optical prescription. There is a distinctive partition between the two parts. The upper prescription is generally used to correct distance vision whereas the lower part is used to correct near vision. Bifocals are usually prescribed to people with presbyopia who need a different prescription for close work.
Varifocal lenses, are also prescribed to people with presbyopia but in contrast to bifocal lenses have no clear dividing lines between the different optical prescriptions. The lenses have a measured change in strength from the top to the bottom, facilitating clear vision at all distances with just one pair of spectacles.
To discuss your lens requirements, please contact McBride and McCreesh Opticians today on 028 6632 2524.