The following technologies and software features are used in Crossbows Optical freeform Rx designs and glass lenses.
Smooth Optics Technology
During the early 2000s, Crossbows Optical R&D developed Smooth Optics™ Technology that reversed progressive lens design by first defining optimum optical properties of each viewing area and letting those calculations create the design. This technology gave the designers direct control over the local curvature of the lens allowing a significantly smoother transition between powers across the progressive design.
BENEFIT TO PATIENT: Smooth Optics provides sharp, comfortable viewing in all fields, minimizes blurring or “swim effect” resulting in a shorter adaptation period and increased patient satisfaction.
EyeView™ Technology uses specially developed software that incorporates the results of raytracing over the entire lens to correct oblique astigmatic and mean oblique error caused by the eye’s variable gaze angle during normal wear. As the eye gazes away from the optical centre of the lens, the optics are distorted.
BENEFIT TO PATIENT: EyeView provides improved image quality in principal viewing areas of the lens. High plus prescriptions result in wider viewing areas than conventional lenses and minus prescriptions benefit from improved distance areas. Overall, EyeView provides more consistent optical performance over the total range of prescription powers for a given design.
Digital EyePower™ is an extension of the EyeView principles, where an individual’s back vertex distance, Pantoscopic tilt and face bow are used to adjust the sphere, cylinder and axis of the prescription to obtain the best “as worn” conditions possible. Special software simulates how the eye views through the lens at any given angle to provide the best correction values.
The wider viewing fields to the lens edge that result from the combination of Digital EyePower and EyeView make freeform lens designs ideal for use in wrap frames. Conventionally surfaced lenses have uncorrected astigmatism away from the optical centre of the lens and wrap frame prescriptions suffer from narrow viewing fields. The astigmatism must be placed on one side or the other of the lens whereas digitally surfaced lenses with Digital EyePower and EyeView provide clear viewing on the entire lens.
BENEFIT TO PATIENT: Vision correction personalized to the patient’s unique prescription, measurements and frame selection. Comfortable, clear vision in wrap frames.
This technology allows the design to be placed anywhere on the lens blank regardless of the semi-finished optical centre without compromising optics. It can be placed on a smaller diameter reducing stock inventory and waste. A flatter base curve can be selected for a thinner, more cosmetically appealing lens profile.
BENEFIT TO PATIENT: Flatter base curves result in great looking eyewear and more frame choices for the individual’s prescription.
Computer software calculates the inset based on the prescriptions near distance, patient’s back vertex distance and monocular pupillary distance as well as the lens power to ensure optimum near viewing field placement.
BENEFIT TO PATIENT: Balanced binocular vision and optimized reading area.
Flatter Lens Curve Selection
Digital surfacing allows the lab to select flatter base curves than conventional processing because of the technologies available to compensate power to correct oblique errors. This is most advantageous when dealing with high prescriptions or wrap frames.
BENEFIT TO PATIENT: Flatter lens profiles for cosmetically appealing eyewear and expanded range of frame choices, especially for patients with high plus prescriptions.
Eyecare professionals can elect to add blocked prism, surface prism or a combination of both as best suits the individual’s visual needs.
BENEFIT TO PATIENT: The flexibility for prism addition provides the patient a more comfortable visual experience.