An intraocular lens (IOL) is placed in the eye after a cataract is removed or during refractive lens exchange surgery. These lenses are made of plastic and stay permanently in the eye after removal of the eye’s natural crystalline lens. They should not deteriorate with time . Intraocular lenses may be either monofocal or multifocal. Monofocal lenses have a single zone of clear focus, usually set for excellent distance vision, but require the use of reading glasses for near tasks, like reading or sewing.
Others, called multifocal lenses, have several zones of clear vision and allow for both distance and near correction. How do monofocal and multifocal lenses work? Monofocal lenses are like a simple camera lens and only give focus at distance. Multifocal lenses give near and distance vision simultaneously. However we do not see things double with them as the brain perceives the clearer image only.
What are the Advantages and Risk of Multifocal lenses?
ADVANTAGES INDEPENDENCE OF SPECTACLES
The main advantage offered by multifocal lenses is the opportunity to become less dependent on reading glasses for near activities. For many people, presbyopia, the loss of the eye’s ability to zoom from distant to near objects, is very frustrating. Activities that were once easily enjoyed without glasses, such as reading or sewing, now require that a pair of reading glasses always be available. For people frustrated by the need for reading glasses, multifocal lenses offer a good alternative.
For example, in the FDA trial of the ReSTOR multifocal lens, lens 84% of ReSTOR patients achieved simultaneous 20/25 distance vision, which is a single line away from perfect 20/20 vision, and near vision which allowed newsprint to be easily read. However, only 23% of patients with monofocal IOL lenses in the same study were able to achieve those levels of distance and near vision simultaneously.
BLUR FROM ABBERRATIONS
Typically, these aberrations are perceived as glare in certain low lighting situations and halos around light sources at night. Most people with multifocal lenses find these aberrations to be only mildly annoying. These generally settle over weeks to months. Haloes are a permanent feature of multifocal lenses but for most are not intrusive especially after the first 6-12 months. However, for those who do a lot of night driving these are not recommended
Reading with these lenses depends on good lighting , having both eyes operated with the reading distance relatively close .
COMPUTER WORK AND NEWSPAPERS
Computer screen distances may be a little burred one may need a week pair of magnifiers for this distance. Generally intermediate vision improves over the period of 6—12 months and after the second eye is operated. Costs of multifocal lenses The additional cost of multifocal lenses for insured patients is $680 per eye for insured patients and $1100 per eye for uninsured patients . Some health funds including HCF AND MBF do not fund multifocal lenses. This is a permanent lens and compares favorably with the cost of a single set of multifocal glasses, that often last only several years with day to day use.
MULTIFOCAL INTRAOCULAR LENSES BERWICK EYE CENTRE ARE THEY FOR YOU?
WHAT CAN GO WRONG ?
Multifocal lenses are essentially the same material and shape as monofocal lenses so the surgical risks are essentially the same .
However, good vision from multifocals require more precise pre-operative measurements of length of the eye and curvature of the cornea. At Berwick Surgicentre we have the most accurate machinery to do this though there remains a small risk of needing “touch-up” refractive surgery or lens exchange to enhance vision afterwards. This may lead to additional costs and risks
ARE YOU A CANDIDATE?
Healthy eyes apart from cataract
Motivation to be glasses independent
Acceptance of night haloes
“On balance multifocals lenses provide a better quality of vision and quality of life ” - Dr Ed Hauptman