Modern multifocal lenses are one of the most complex types of glasses to provide for patients. You can liken them to professional camera lenses, where different lenses can give drastically different visual effects.
Why were multifocals invented?
Before multifocals were invented, we could only choose from getting reading glasses or bifocals when our eyes weaken with presbyopia (especially beyond the age of 40),
The problem with bifocals was that neither the top or the bottom part of the lens will keep objects at the intermediate distance (such as a computer, or a newspaper on a table) in focus; and it has an ugly line on the lens. Reading glasses were no better because they had to be constantly put on and taken off.
Multifocals were developed to solve both problems, providing a lens with no visible lines that can be left on and provide continuous vision from distance, intermediate, to reading.
How do multifocals work?
Multifocals have three zones of vision:
- Distance zone – at the top of the lens, and used to watch TV, drive, and see far away.
- Intermediate zone – typically the most variable between basic and advanced designs
- Reading zone – at the bottom of the lens, for use when reading books, phones and tablets.
These three zones of vision are contained within a channel in the lens; outside of which objects will appear blurry.
How can multifocals differ?
1. Corridor Length
Some multifocal designs are optimized for better computer vision at the expense of close up reading performance; while other multifocal designs do the exact opposite. During a comprehensive eye exam, we can determine which type of design will suit your needs best; and during the dispensing process, we will also need to take into account the type of frame shapes you prefer.
2. Age and Quality of Lens Design
Older and more basic multifocal designs tend to have a much narrower channel of clear vision compared to newer and more advanced designs.
3. Frame Selection, Measurement, Alignment
It is the experience and skill of the optical dispenser that can help guide each patient to select an appropriate frame for their multifocal design. Frames that are too narrow or frames that sit too far from the eyes will both reduce the viewing areas of the multifocal. Accurate measurements by the optical dispenser and optometrist will determine the effectiveness of the lens design. Lastly, correct frame alignment to the face of the patient will ensure that the measurements taken are both precise and accurate.
How can I pick the right multifocal?
Ultimately it is the responsibility of the optometrist and optical dispenser to choose the right multifocal that suits your lifestyle, fashion, budget, eye health, and prescription. Because there are so many factors involved, dispensing multifocals can be one of the most difficult jobs to get right.
At our practice, our optometrist Yang has knowledge of the latest multifocal designs that will suit your needs, while our certified optical dispensers Birgit and Hong has over 45 years of combined experience to ensure that we can troubleshoot any problems you may have adapting to multifocals and ensure you end up with a pair of multifocals you enjoy.
At Eyecare Plus Corrimal, we are confident in the multifocals we prescribe and we provide a comfort guarantee to ensure that new multifocal wearers will be happy with their glasses. Click here to book your next eye exam instantly.