Word of mouth can be very powerful, in a positive and especially in a negative way. People often talk about how wonderful something is, but if it didn’t work for them, they become much more inclined to steer others away from it.
When your optometrist prescribes multifocal lenses for the first time, it’s natural to feel a little anxious. You may ask: how does it work, why do I need it, will I adapt to it or will I like it? You may even know someone (or be married to someone) who couldn’t adjust to these lenses at all.
The history of the multifocal Lens
As the name suggests, multifocal lenses enable wearers to have multiple prescriptions built into one lens. Multifocal lenses are custom-made and allow the wearer to see distance, intermediate and near objects. In simple terms, distance may be described as 6 meters and beyond, intermediate as arms’ length and near as at about 40 centimeters.
The lens powers are progressive and seamless, unlike bifocal lenses where a line is visible and you only enjoy distance and near vision.
The origin of the multifocal lens design is rooted in the bifocal lens, first invented by Benjamin Franklin in the 18th century. His invention gave spectacle wearers the ability to see in the distance as well as read, while wearing the same pair of spectacles. He used two single vision lenses in the correct prescription for near and far vision, cut them in half and glue them together before fitting them into a frame. This, of course, was a very unsightly lens. Other disadvantages were that the image jumped when looking from distance to near focus, and the lack of intermediate focus.
Manufacturers tried hard to make the line less noticeable by inventing the blended bifocal. The lens looked slightly more appealing, but it was still unsightly! Some people refused to wear the lined lens as they felt it gave their age away!
Researchers started working on new lens designs, which were, not only much more cosmetically pleasing, but would also cater for modern-day visual tasks. The aim was todesign a multipurpose lens that would allow the patient the convenience of seeing distance and intermediate (arms’ length) while being able to read clearly at 40 centimetersand all of this from a single lens design. This was the birth of the multifocal lens.
With this new design came another problem, namely, peripheral distortion. This meant that, should the wearer look down to read but the head positioning is incorrect, vision may be out of focus. Optical engineers continued searching fordesigns that would diminish peripheral distortion.
Not all multifocals are the same; there are older designs that may require longer adaption times and have greater peripheral distortion. Peripheral distortion often occurs when the new lenses are of a higher prescription or the frames are larger than what you were used to.
New multifocal designs are continuously being developed. The latest range of digitally enhanced free form lenses provide wider distance, intermediate and near vision. These designs allow easy adaption and comfort for the wearer. New generation lens designs are generally more expensive.
During the visual examination, your optometrist (or optical dispenser) will ask questions to determine your visual needs. Your answers will guide him/her towards suggesting the correct multifocal design to suit your specific lifestyle needs and occupational requirements.
Do I need a multifocal lens?
If the lens you need to correct your distance vision is different to that of your near vision,and you don’t want to carry around two pairs of spectacles, the multifocal lens is for you!
How long does it take to get used to multifocal lenses?
We are all individuals and we all have different visual needs. When collecting your new glasses, the optometrist or a dispenser will teach you how to use your lenses. Some patients leave with little to no concern while others require a few days to adapt. The better the design, the easier the adaption.
A person under the age of forty, who is emmetropic (no refractive error), has perfect functional vision. What this means is, that the visual system can cope with all visual demands at any distance. The focusing system of the eyeis incredibly flexible and agile until we reach the age of about forty. For aperson over forty, or who has a refractive error, it is a different kettle of fish. Multi focal lenses go a long way in providing functional vision at different distances, but it is important to recognise that no lens design will ever cover all the bases in providing all round functional vision. The failure of the new multifocal wearer to recognise this fact, is often at the root of difficulty to adapt.
For optimal enjoyment of your new multifocal lenses, keep the following in mind:
- Ensure that your optometrist understands your visual needs before prescribing your multi focal design. You may need a lens design with a wide corridor when you are working at a desk or on a computer all day.
- Remember: The lens has been designed to work with the natural lowering of your eyes.
- Read with your nose – point your nose in the direction of what you want to focus on.
- Fitting – your frame must be adjusted correctly before any measurements are taken. If the fitting height is too low, you may find that you need to lift your chin for clear focus. If the fitting height is too high, you may have to lower your chin to focus in the distance – or to drive.
- An “office multi focal” is an option for optimal vision at near and intermediate distances.
- You may need more than one pair of glasses to fulfil all your visual functions.
Benjamin Franklin may have had the multifocal lens in mind when he said: “He that can have patience, can have what he will.” Choosing a multifocal lens may be one of the best decisions you have ever made!