FREE-FORM LENSES

QUALITY OF LENSES - ARE YOU COMPARING THE SAME PRODUCT?

Is it apples-to-apples?

Why do lenses vary in price when they all look the same? Lenses are highly technical products that in many cases will require a greater investment than your frames. As the differences between them is not always apparent, comparing like for like can be difficult. It basically comes down to how well you want to see with the lenses, how much are you educated about the kind of lenses you get and which options are selected from the following categories.

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CONVENTIONAL LENSES VS. FREE-FORM LENSES (DETAILED)

Q: What are conventional lenses?
1. They use "pre-molded" templates
2. You may notice that they lack clarity or uncomfortableness with them

Q: What are free-form lenses?
1. They are lenses designed by computers to eliminate the five most common challenges in off-axis vision: spherical aberration, oblique astigmatism, distortion, coma, and curvature of field.
2. It is calculated with further personalized measurements called position of wear (POW). These measurements include pantoscopic tilt, vertex distance, and face-form wrap from the frame to the patient's eyes.
3. With this calculated algorithm, a patient will experience greater precision over the entire lens surface allowing the patient with more visual comfort, improved peripheral vision, sharper definition, and less eye fatigue.

Q: Are digital lenses the same as free-form lenses?
1. No. All free-form lenses are digital, but not all digital lenses are free-form.
2. There is marketing confusion between the terms: "digital lenses" vs. "HD lenses" vs. "free-form lenses".
3. A company can market "digitally" surfaced lenses to claim increased accuracy, BUT it does not improve the patient's visual experience if position of wear (POW) is not measured.
4. Free-form lenses need POW measurements. This allows for precise lens designs that can be tailored to all types of visual demands. There are no predetermined lens blocks or special tools for polishing. Free-form lenses can be refined to 1/100 of a diopter or 10 times more than a standard conventional lens.

HOYA Free-Form Lenses

These refinements have optical advantages. Some comparisons made from a conventional lens design to a free form lens is like picking a suit off the rack compared to a finely-tailored suit – or perhaps viewing a standard TV screen versus viewing a high definition TV.
The true advantage is the advanced computer algorithms that are used to incorporate lens technologies into the lens design, maximizing binocularity and optimizing the progressive corridor.

Using advanced and complex computer algorithms to direct the diamond tip lathe, you can bring extreme precision to the lens design. A handful of factors are used in calculating each design, and there are two patented technologies that separate HOYA from the rest.

1) iD technology
iD technology takes into consideration the front and back surfaces of the lens. This technology calculates the vertical components of the reading corridor and places it on the front surface of the lens and the horizontal components on the back side. This allows the eyes to rotate quicker and more efficiently, downward through the corridor to get to full reading power – and it creates a wider corridor zone in the horizontal position.

2) Binocular Harmonization Technology (BHT)
BHT takes into consideration the prescription of each eye individually and designs the lenses as a pair, working together. Around 70% percent of the population has anisometropia or a difference in prescription between their two eyes.

This can be significant when the eyes rotate down the progressive corridors, as the reading powers will differ between the two lenses – especially the larger the anisometropia. The BHT computer algorithm takes this into consideration and adjusts the power distribution and corridor lengths to allow the eyes to work equally together, in binocularity, when viewing at near.

The Perks of Personalization

HOYA’s premium lens designs are actually free form surfaces, both on the front and back sides of the lens for total personalization.

The beauty of free form technology is the ability to personalize. With the accuracy of 1/100 of a diopter and the ability for complex computer algorithms to incorporate advanced lens technologies, such as iD and BHT, superior optics for any task can be created. This allows you to tailor the lens design around your patients daily visual demands, making adaptation much easier.

Utilizing position of wear (POW) measurements brings another level to personalization. Think of the lenses in a frame sitting on the face as having a 3D position relative to the eye. There will be a certain wrap and tilt to the lens in the frame. Also, there is a distance from the back of the lens to the front of the eye. If we take into account these positions of wear, free form technology can enhance the wearing prescription even more – and also enhance the viewing prescription and the corridor size as compared to a conventional lens.