View source for Varilux

== Varilux ==

'''Varilux''' is [[Essilor]]'s progressive addition lens brand and the first commercially
successful progressive lens. It was invented by Bernard Maitenaz, patented in 1953 and launched
in May 1959. Over 700 million Varilux lenses have been sold since.

=== The 1959 trial ===

Before release, Varilux was tested on 46 people in January 1959. The recorded outcomes were
5 excellent, 29 good, 2 average and '''10 poor'''. The lens launched four months later.
Roughly 22% of the founding trial did badly, so non-adaptation was documented from the start
rather than discovered later by wearers.

=== Why the peripheral blur cannot be removed ===

The distortion at the sides of any progressive lens is a geometric consequence, not a
manufacturing defect. '''Minkwitz's theorem''' (see Sheedy & Campbell, ''Optometry and Vision
Science'', 2005) states that along the umbilical corridor of a progressive surface, unwanted
astigmatism perpendicular to the corridor increases roughly '''twice as fast''' as the mean
power increases along it.

Two consequences follow:
* A stronger reading add, or a shorter corridor, produces proportionally worse peripheral blur.
* The distortion can be '''redistributed''' across the lens surface but '''cannot be reduced'''.

This applies to every progressive lens from every manufacturer. Premium designs relocate the
distortion according to assumptions about gaze behaviour; they do not remove it.

=== Current product lines ===

The current flagship is the '''XR series''', marketed as "eye-responsive" and using three named
technologies: Nanoptix, Xtend and XR-motion. '''XR Comfort Max''' claims an extended near zone.
Older '''X series''' and '''Physio''' lines remain on sale. Street prices range from about
$139 a pair online to $700-$900 or more for XR with coatings through a retail optician.

=== Documented risks ===

* Progressive lens wearers fall at roughly twice the rate of bifocal wearers: adjusted odds
  ratio '''2.23''' (Lord et al., ''Optometry and Vision Science'', 2025, n=281). Falls per person
  2.31 against 1.61.
* Multifocal wearers fall about '''2.3 times''' as often as non-wearers (Lord, Dayhew & Howland,
  ''Journal of the American Geriatrics Society'', 2002, n=156).
* Toe clearance becomes more variable in multifocals, though the mean is unchanged
  (Johnson, Buckley, Scally & Elliott, ''IOVS'', 2007).
* A randomised controlled trial found that giving single vision distance glasses to multifocal
  wearers '''reduced falls in those with regular outdoor activity''', while noting the switch
  '''may be harmful for low-activity wearers''' (Haran et al., ''BMJ'', 2010, n=606).
* Peripheral distortion measurably corrupts optic flow, producing a false sense of upward
  self-motion on level ground (Sauer et al., ''iScience'', 2021).
* Progressive wearers develop a distinct eye-head coordination pattern, holding the eyes near
  centre and turning the head instead (Rifai & Wahl, ''Journal of Vision'', 2016).

The reading segment at the bottom of the lens is focused at roughly 40 cm. Floor distance is
around 150 cm, so the part of the lens used to see the ground is out of focus for the ground.

=== The endmyopia position ===

Two pairs of [[single vision]] lenses, one for distance and a deliberately weak pair for close
work, remove the corridor, the peripheral distortion and the out-of-focus lower field entirely.
See [[Differential Glasses]] and [[Presbyopia]].

=== External links ===

* [https://endmyopia.org/varilux-lenses-review/ Varilux lenses review: what the research actually shows] (endmyopia.org)
* [https://endmyopia.org/progressive-lenses-vs-bifocal-lenses/ Bifocal lenses vs progressive lenses]
* [https://doi.org/10.5281/zenodo.21016339 EndMyopia Case Report Registry, DOI 10.5281/zenodo.21016339]

[[Category:Lenses]]
[[Category:Presbyopia]]