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DIGITIZING SINGLE VISION
A New World of High-Tech Innovations for Optical’s Original Spectacle Lens BY JEFF HOPKINS
While progressive lenses are an eternal making eyeglasses, which make for good there. Spherical lenses provided excellent While progressive lenses are an eternal topic in our power for correcting astigmatism were developed in
topic in our industry, single vision vision.” (This could also be the first example vision if the most appropriate base curve was
ilnendsuessatrey,ofstiengolveervloisoikoend. Ilet’snesaessy taorseeoftoefna coevlebrrliotyoekyewde.ar entdhoersemarelnyt.1) T9hthesecenutuserdy.foOr bthveiopautiselnyt,’stphresceraiprtliyone.vHooluwteivoern,
why: The product category is literally ancient, early eyeglasses had convex lenses that could for stronger prescriptions, a spherical lens
It’s easy to see why: The product category is literally of lenses moved slowly.
and the great majority of single vision lenses provide reading vision for presbyopes and
could be thick and bulgy. One way to address this was to use a lens with a flatter front curve.
ancient, and the great majority of single vision
sold can be considered a commodity product. correct hyperopia (Fig. 1). Concave “minus”
lenses sold can be considered a commodity product.
n to appear in the
FIG. 1
TORIC
nses evolved beyond , but the need was
However, since this would not be the ideal front curve for the prescription, the wearer would not have clear vision across the full height and width of the lens (how much it was restricted depended on the patient’s prescrip- tion and the curve chosen.) In short, wearers with stronger prescriptions had to choose between the need to see well and the desire to look good.
In the 1950s, a solution was developed that greatly reduced the need for compromise: aspheric lenses. This type of lens has a curva- ture that “flattens out” between the center of the lens and the edge (Fig. 2). The chang- ing curvature creates surface astigmatism
However, the latest single vision lenses and lenses for myopia bega
However, the latest single vision lenses and other
other new types of lenses for younger wearers 16th century, and the
new types of lenses for younger wearers are as
are as advanced in technology as the latest first lenses with cylin-
aprdovgarenssciveedleninses.tAencdhnthoeliongnoyvaatiosnsththey latdeestr porwoegrrefosrsivcoer-
lemnbsoedsy.coAulnddbentehfiet mianny yoovuantgieorneysegtlahssey remctibnog daystigcmoautlidsm
wearers—ifonlytheyknewaboutthem. were developed in
bene t many younger eyeglass wearers—if only
the early 19th centu- ry. Obviously, the early evolution of lenses moved slowly.
enough, in a sermon delivered in 1306 by SINGLE VISION not known for certain; the rst reference we have to
they knew about them.
ORIGINS
Singlevisionlenseswere,ofcourse,theorigi-
ORIGINS
nal spectacle lenses. Exactly when they were
Single vision lenses were, of course, the original
invented is not known for certain; the first srepfercetnaccelewelehnasvest.oEsxpaectalyclwes hise, nodtdhley y wAeSreP HinEvRenI CteAdNisD A
Friar Giordano de Pisa. He wrote, “It is not It was much later that le
spectacles is, oddly enough, in a sermon delivered
yet 20 years since there was found the art of strictly spherical curves
in 1306 by Friar Giordano de Pisa. He wrote, “It is
40 • June 2020 20/20
not yet 20 years since there was found the art of
making eyeglasses, which make for good vision.” (This could also be the rst example of a celebrity eyewear endorsement.) These early eyeglasses had convex lenses that could provide reading vision for presbyopes and correct hyperopia (Fig. 1). Concave “minus” lenses for myopia began to appear in the 16th century, and the rst lenses with cylinder
65 EYEZONE Issue 91-92 May / August 2020