Advantages and disadvantages of FreeForm

Written by Optician Club on . Posted in Freeform Rx Lenses, Optician News, Progressive Lenses

What can be done by advanced ophthalmic design and free-form technology and what is Advantages and disadvantages of FreeForm?

  • Optimize the lens for the power that the user perceives, not the power measured in the focimeter (which is ok for quality control, but is not the power perceived by the user)
  • Optimize the lens for any position of use (tilts, distance to the eye, etc…)
  • Optimize the lens for any base curve
  • Optimize the lens for each prescription and frame data
  • Optimize the lens for particular applications
  • Better control of lens thickness
  • Off-centering without losing optical quality
  • Important improvement to the optical quality of standard lenses
  • Progressive lenses that violates Minkwitz’s theorem (PALs with wider corridors for the same corridor length)
  • Lenses without aberrations
  • PALs without adaptation period
  • Short PALs with intermediate wide enough for computer displays

Advantages and disadvantages of FreeForm

Myths

  • Free-form PALs will always provide wider field
  • Free-form PAL may have bad designs!
  • Free-form PALs will always have wider intermediate
  • It only depends on the corridor length, and not on the PAL technology!
  • Free-form PALs don’t have aberrations
  • Any PAL must have unwanted astigmatism. Pay attention to any other higher order aberration is useless!
  • Free-form PALs are easier to adapt to
  • Only if the design is good, adaptation will be easier

You may also need to learn about miss-conceptions about Freeform progressives

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