Digital single vision utilized atoric design, meaning there are complex curves on the back lens surface to produce better edge-to-edge clarity and reduce many common lens aberrations. Much like conventional aspheric designs, single-vision digital lenses reduce the optical effects of minification or magnification of high powers and the corrected curvature of the lens produces flatter … Continued
The benefits of freeform lens design are not limited to progressive lens wearers. Many offices have transitioned to only offering freeform progressive technology but have yet to embrace the benefits of single-vision digital, anti-fatigue, or digital bifocal lens styles.
The more finite increments of corridor lengths available in freeform design means that each progressive can allow optimal real estate distribution to focal lengths in all shapes and segment heights. Variable corridors assigned by the lens design algorithm greatly improves the utility of the progressive in any chosen frame depth. The option to choose a … Continued
Most digital lens designs will be customized for optimal fit and prescription distribution in your frame based off the measured segment height. Conventional designs have a fixed length between distance and near correction and are at most offered in a long or short corridor option. Not only do most digital designs have multiple lengths in … Continued
Some lens designs offer customizations that can enhance the width of specific focal ranges based on lifestyle preferences or prescription needs. Progressives can offer alternative designs that provide more generous distance, near, or intermediate focal zones. These choices can be inspired by a conversation with the patient about what improvements can be made from their … Continued
Proprietary devices made by lens companies to analyze eye movement and gaze direction have been around for over a decade now, but these devices are getting much more sophisticated all the time. Earlier mechanisms were often in the form of a freestanding device or even tablet app that would determine how you move your head … Continued
The further personalization of digital lens design can consider many factors of preference and use. Progressive contours can either be steep or soft based on the patient’s tendency to move their head or eyes more when changing gaze direction. Other strategies involve questionnaires or activity assessments that can point to customized design options. The optician’s … Continued
When our eyes focus on distant objects, both pupils are straight forward. As an object gets closer, the alignment of our eyes must also get closer together. This convergence for near focus is accounted for in all multifocal designs by insetting the near zone from the distance alignment. Conventional designs must provide the same near … Continued
Base curve variability is a type of dual surface design. As previously described, a lens manufactured on the optimal base curve can control the optical accuracy in a larger window of the lens and reduce aberrations. Optimizing base curves with a larger selection of smaller increments of single vision spherical curves is a huge advantage … Continued
Digital surfacing technology is always done on the back side of a lens. When a company claims dual surface design, that means the lenses are not starting with a spherical single-vision lens blank. Instead, they produce specialty molded aspheric pucks. This allows for an even more complex design and claims to have better ability to … Continued
There are many types of electronic devices to assist in frame parameters on the market today. They are all intended to give us the values of vertex, wrap, and tilt, but each has a unique set of additional features. Most devices will provide box measurements for frames as well as PD, optical center height, and … Continued
We have a variety manual devices to obtain position of wear measurements. These include various contraptions such as wrap layout charts, suction cup pantoscopic anglers, distometers, and even PD rulers. The distometer has been around much longer than digitally compensated lenses. This device measures vertex distance by resting on the closed lid and reaching an … Continued
Digital lenses are often compensated whether or not measurements are provided. An optician can pre-adjust the patient’s frame and take the actual measured values of vertex, panto, and wrap on the patient to supply in the lab order for the prescription compensation. If these custom measurements are not provided, the lens design usually uses default … Continued
There are three positions of wear that can be measured and used to calculate lens compensation: vertex distance, pantoscopic tilt, and frame wrap (also called faceform or panoramic angle). Vertex distance is measured from the back surface of a lens to the front of the eye. Vertex variations change the perceived spherical power of the … Continued
Most digital lens designs today offer a lens compensation. Compensating a prescription means the lens is intentionally fabricated with different lens powers than prescribed. Some specialty designs such as office lenses will compensate the doctor’s distance prescription to an intermediate-near format. However, most lens compensations exist to correct for common errors in the viewed prescription … Continued
The keyhole effect is the claim that processing the progressive corridor and magnification on the back side of the lens brings it closer to the patient’s eye thus producing the effect of putting your eye closer to a keyhole and broadening your view making the corridor and focal zones appear wider. Some digital lens companies … Continued
There are many optical errors that can occur with imprecise focusing of light through a lens that can reduce visual clarity, even if a lens is surfaced accurately. These aberrations are not caused by the patient’s vision, but by the lens itself. Aberrations are defined as any property of a lens that results in an … Continued
We know that the very nature of digital processing reduces many obstacles and limitations of lens curve and availability, but what else can we do with these capabilities? Optical manufactures are on an even playing field as far as surfacing equipment and ability. Every established optical lens company is now up against newer digital lens … Continued
Conventional progressive designs are created by a mold of add progression that is duplicated exactly for each patient who is fit with that lens. Conventional design can be compared to a rubber stamp that creates exact duplicates of a single design. A freeform generator has a single-point diamond cutter that can create any design imaginable … Continued