But if you have a strong prescription and you’re ordering your glasses online, figuring out how to get the thinnest lenses possible can be perplexing.
Not to worry!
We’re going to make it easy for you.
All you’ll need is your prescription and a handy online tool that will estimate how thin your lenses will be.
This handy online tool is the Lens Thickness Calculator. It can be found here, at the OptiCampus website.
Before we talk about how to use the Lens Thickness Calculator, let’s look at the factors that can thin your lenses:
1) Your prescription. This you cannot change to get a thinner lens. Doing so would be counterproductive, in that you would not be able to see well if you take it upon yourself to lower your prescription below what your eye doctor has prescribed.
As a general rule, single vision prescriptions result in thinner lenses than multifocal prescriptions, all things being roughly equal. Multifocal prescriptions are those with an NV-ADD (Near Vision reading ADDition). Having an NV-ADD, or just an ADD, as it’s usually written, enables you to get bifocals and progressive glasses.
In addition, prescriptions with astigmatism corrections – if you have this, there will be numbers in the Cylinder (CYL) and Axis (sometimes abbreviated X) fields – generally result in thicker lenses than those without astigmatism corrections.
2) Your lens index. The lens “index” is short for the lens’s “index of refraction.” That means how much the lens bends the light that enters it. That’s what refraction is. Bending the light focuses it right into the middle of your visual sweet spot, the retina, so you can see well.
You can change the index to thin the lens, up to a point. After that point, the law of diminishing returns kicks in. The lens that is recommended for your prescription will be the thinnest lens. Choosing a lens index that’s higher than the recommended lens index won’t make the lens thinner, and you’ll end up paying more for no improved result.
If this is confusing, don’t worry. We’ll clearly explain where the point of diminishing returns shows up when we look at the various lens indexes. In addition, you’ll be able to see it too, when you start playing with the Lens Index Calculator.
3) Your lens width. This can have a considerable effect on your lens thinness. Once you have settled on the correct lens index, having determined that going to a higher lens index number won’t result in a thinner lens, the lens width – also known, weirdly, as the “eye size” – will be the last, and in some situations, the most important – factor in thinning your lens.
OK, are you confused enough yet?
Yes? Let’s fix that right now.
We’re going to look at a prescription to see how different index numbers can make the lenses thinner. We’ll change the lens width – remember, that’s also known as the “eye size” (even though it doesn’t refer to the size of your eye) – to see how this affects the thinness of the lens.
To do this, we’re going to use a fairly common prescription. Most eyeglasses wearers are nearsighted, which means that the number in the Sphere (SPH) section on the prescription will be minus.
Most people who have an SPH correction also have an astigmatism correction. So we’re going to create a common prescription, with an average Pupillary Distance (meaning the distance between your pupils measured in millimeters, PD for short), 63; an average lens width (all together now: also known as “eye size”), 50 mm; and an average bridge (that’s the part of the frame that goes over your nose), 18 mm.
Here it is:
SPH -2.00, CYL -1.00, AXIS 90, PD 63, Lens Width 50, Bridge 18.
(For the sake of simplicity, we’ll assume that the prescription is the same for both eyes.)
Let’s put these numbers into the Lens Thickness Calculator and see what we come up with when we use different lens indexes.
With nearsighted prescriptions, the lens is concave. With farsighted prescriptions, the lens is convex. A concave lens is thinner at the center, thicker at the outer edge. A convex lens is the opposite.
You will see then, that with nearsighted prescriptions, the Center Thickness of the lens will be a lower number than the Edge Thickness.
Here’s what our formula yields with the 1.50 standard-index lens, which comes free on an order of single-vision glasses:
Center Thickness (CT): 2.0 mm / Edge Thickness (ET): 4.4 mm
Nice and thin at the center, but maybe not as thin as it could be at the outer edge. Let’s try it with the 1.57 mid-index lens and see what we get:
CT: 1.5 mm / ET: 3.6 mm
That makes the lens thinner at both the center and edge, and the lens is still free. Now let’s try it with the 1.59 pure polycarbonate single-vision lens, which costs $9.00, and see what happens:
CT: 1.5 mm / ET: 3.5 mm
You’re spending $9.00 for this lens, which is not a huge amount, but this slightly higher index doesn’t make the eyeglasses lens perceptibly thinner than the free 1.57 lens does. Now we’re starting to see the law of diminishing returns come into play.
However, even if the lens would be just as thin with the 1.57 lens, it would be worth it to spend the $9.00 on the 1.59 pure polycarbonate lens if you’re getting rimless glasses or if you’re buying glasses for kids who can be expected to treat the glasses roughly.
That’s because the 1.59 lens is a more impact-resistant lens than the 1.57, which is still a fine lens for people who treat their glasses with care.
Now we’re really going to see the law of diminishing returns at work when we go up a notch, to the 1.61 high-index single-vision lens. Here are the results of this lens:
CT: 1.5 mm / ET: 3.5 mm
No change, and you’re now (theoretically) spending $19.95 on a lens that isn’t any thinner than the 1.59 pure polycarbonate lens that’s $9.00, and is only a tiny bit thinner than the 1.57 mid-index lens that’s free.
But even after you’ve selected the lens index that will give you the thinnest lens, you can still thin the lens further, if you narrow its width.
Let’s lower the lens width to 48 mm and see what happens with each lens. First, the 1.50 lens:
CT: 2.0 mm / ET: 4.1 mm
The Edge Thickness is a tiny bit better, 4.1 mm as opposed to 4.4 mm on the 50 mm-wide lens. How about the 1.57 lens?
CT: 1.5 mm / ET: 3.3 mm
Now we’re talking! We’ve shaved half a millimeter from the center and almost a whole millimeter on the edge, just by lowering the lens width.
How about with the 1.59 lens?
CT: 1.5 mm / ET: 3.2 mm
No change on the center, only one tenth of a millimeter on the edge. Stand and salute the diminishing returns on parade!
Let’s take a quick look at the 1.61 lens, just to make sure it doesn’t make the theoretical eyeglass lenses any thinner:
CT: 1.5 mm / ET: 3.2 mm
That would cost $10.95 more for no improved result.
So unless you want a pure polycarbonate lens for its impact-resistance feature, you’re wasting your money by spending $9.00 to get a higher-index 1.59 lens that won’t be any thinner than the free, 1.57 mid-index lens.
But once you’ve confirmed which lens index that will result in the thinnest lens for your prescription, and you want to thin the lens even further, play around with the lens width on the Lens Thickness Calculator. Go as low as you can and still keep the lenses wide enough for a comfortable field of vision and attractive look.
For example, the 48 mm wide lens may be just as narrow as you can go without making the glasses look too small. But if you can narrow the lens even more, you will see that the lens will continue to become thinner.
If you do check out the Lens Thickness Calculator to see the estimates of different thicknesses that different lens indexes and lens widths yield, keep a few things in mind: When you are selecting the Lens Material Type, the categories listed on the Lens Thickness Calculator don’t exactly correspond to the lens index categories on our website, although they are basically the same.
For example, the Hard Resin lens is the 1.50 lens. The 1.56 mid-index is essentially the same as the 1.57 mid-index. The polycarbonate lens is the 1.59 mid-index lens. All of the 1.60 lenses on the Lens Material Type list are the equivalent of the 1.61 high-index lens.
So to recap, stick with the lens that our website recommends when you enter your prescription. That will get you the thinnest lens for your prescription, if you also select the lowest lens width that will also work well for your face size and shape.
Thursday, February, 13 2014 by Matthew Surrence
Andrew Campbell of North Charleston, S.C., made an animated video showing the process from ordering Zenni glasses to receiving them in a warm, inviting, and entertaining 28 seconds. “From start to finish, this video took about 25 hours spread over the course of about a week. I had to motivate myself to make it the best it could possibly be, regardless of how long it took,” Campbell said.
Getting to know our winners:
Zenni: Did you write, direct, and perform in the video?
Andrew: I was the writer, director, illustrator, and animator of my video. As I was on a bit of a budget, I was also the narrator.
Zenni: How long did the shoot take?
Andrew: From start to finish, this video took about 25 hours spread over the course of about a week. The only challenge I faced while making my video was myself. Since I created this entirely on my own, I really had to motivate myself to make it the best it could possibly be, regardless of how long it took.
Zenni: How long have you been doing animation?
Andrew: I started animating only a couple years ago when I took some classes about the technical aspects, as well as design principles.
Zenni: Do you have any heroes in animation?
Andrew: I really admire Seth MacFarlane and Matt Groening. Their writing is top-notch.
Zenni: How many pairs of Zenni glasses do you own?
Andrew: To be honest, I don’t personally own any Zenni glasses, but I have a few close friends that swear they are the best.
Zenni: What other hobbies do you have besides filmmaking?
Andrew: Some other hobbies of mine, besides filmmaking, are cooking, running, and playing guitar.
Zenni: What will you do with the prize money?
Andrew: The money I win will go toward paying student loans (recent film grad, here). Ah, what the heck, I might put some toward a video editing computer.
To check out more of Andrew’s work, visit his website!
Monday, February, 10 2014 by Matthew Surrence
Andie Bottrell of Springfield, Mo., tickled the judges with a zany video she wrote, directed, and starred in, which shows her blurry-vision point of view – until she finds a pair of round tortoiseshell Zenni glasses attached to a tree. Now with clear, crisp, corrected vision, Bottrell frolics in the snow. At the end of the day, she even puts on her glasses to go to sleep, which she confirmed she actually does. “All the better to see my dreams with,” she said.
Check out her video below and tell us what you think in the comments!
Getting to know our winners:
Zenni: Did you write, direct, and perform in the video?
Zenni: Who were the actors in the video?
Zenni: How long did the shoot take?
Andie: 3-4 hours.
Zenni: Did any funny or weird or troublesome things happen on the shoot?
Andie: Not especially, though I’m sure the neighbors shoveling their snow where wondering why the hell I kept running into that tree.
Zenni: What were the special challenges you faced in making this video?
Andie: I just moved to Springfield, MO and didn’t know anyone to build a cast and crew in time, so I had to do it all myself- writing, directing, filming, acting, editing, sound. The most difficult challenge was being both behind and in front of the camera at the same time- this required tying my camera to a tree branch and to the shower to get the shot.
Zenni: Have you won in other contests before?
Zenni: How many Zenni Pair you own?
Andie: One, so far. I had just ordered my first pair- I’d been searching for the past year for glasses like this (round like Anna Karina’s- or Harry Potter- or John Lennon depending on your age and genre preferences)- when I read about the contest.
Zenni: How long have you been shopping with Zenni online?
Andie: The past few months.
Zenni: Full-rim, half-rim or rimless?
Andie: Full rim.
Zenni: How did you come up with idea for your video?
Andie: Personal experience The past few months I’ve found myself opting for my glasses over my contacts, and not just for lazy reasons, but for aesthetic reasons. I thought your customers would probably relate.
Zenni: Do you have other hobbies apart from filmmaking?
Andie: Filmmaking is my passion and my pursuit- primarily writing, directing, acting and editing. I do enjoy all creative field, though, from music to painting to photography.
Zenni: If you had only two words to describe Zenni Optical what words would you use?
Andie: Affordable & Good-lookin’
Zenni: Why do you wear glasses?
Andie: I started wearing glasses in the third grade because I could not see the big E. When I was a teenager, I got contacts. I wear glasses today because I love the way they look.
Zenni: How will you spend the money (Will you spend your money on new glasses)?
Andie: Of course! Glasses for the whole family! Glasses for the dogs! Glasses for the glasses! Truthfully, I would love to be able to buy a new camera with some nice camera lenses- you don’t happen to sell those, do you? (:
Questions about the crew:
Zenni: What inspired you to create and use this wacky voice?
Andie: I have no recollection of where that voice came from or why- I presume it came, like all great art, from the ether.
Zenni: Do you really sleep in Zenni Glasses?
Andie: Oh, yes. All the better to see my dreams with.
To find out more about Andie, go check out her website!
Sunday, February, 9 2014 by Matthew Surrence
When did Presidents Day become all about white sales?
I mean, c’mon! What do towels and bedding have to do with George Washington, Abraham Lincoln, or any other president for that matter?
(All right, we know what you’re thinking, but please move along. There’s no Clinton joke to see here. There wasn’t any bedding, although towels may have been involved.)
But hey, it’s time to move on! So toss that rumpled bed linen in the hamper, along with the stained blue dress, and let’s get serious.
To properly honor our presidents, instead of sheets and pillowcases, our last three-day weekend before the long drought until Memorial Day should be all about … glasses!
Yes, glasses. Work with us here.
Now we know that when you think POTUS (the acronym for President of the United States) you may not immediately think GOTPOTUS. (That’s glasses of the POTUS, not a parody of a milk commercial or a sign the rest of the country will soon follow Washington and Colorado.)
But you should. Eyeglasses have played an important role in the lives of many U.S. presidents. And in the case – literally, the eyeglasses case – of Theodore Roosevelt, a lifesaving role!
Roosevelt favored pince-nez (pronounced “ponce-NAY”) glasses, which perch right on the nose and are held in place with nose pads.
He was running as the Progressive Party candidate for president in 1912 after he failed to wrest the Republican nomination from his successor as president, William Howard Taft. Roosevelt was on his way to make a speech in Milwaukee when a would-be assassin shot him outside his hotel. Here he is, just before he was shot:
Although the bullet pierced Roosevelt’s skin and lodged against one of his ribs, its trajectory toward the former president’s heart was stopped by Roosevelt’s bulky overcoat, his folded lengthy speech, and (wait for it) his steel-reinforced eyeglasses case.
Was that sound we just heard the sound of you moving your eyeglasses case to your breast pocket? Don’t worry, you’re probably safe, unless you live in Florida.
Roosevelt, whose machismo was unimpeachable, was the first president to be photographed wearing glasses. He knew he wasn’t a namby-pamby, or if he secretly knew he was a namby-pamby, he made sure his well-publicized exploits indicated otherwise.
But most presidents, being politicians and as vain as actors – heck, they are actors! – have preferred not to be photographed (or painted) wearing eyeglasses.
That’s why you won’t see a pair of glasses anywhere on a dollar bill – not on Washington, not on the pyramid’s eye on the greenback, and certainly not on the eagle-eyed eagle. But our first president was also the first president to wear glasses, and he rocked them, in a frame of solid silver:
Washington also sometimes read with a lorgnette (French eyeglasses on a stick), a cherished gift from his Revolutionary War comrade the Marquis de Lafayette.
Washington’s prescription in his silver-frame glasses is +3.50, making them fairly strong reading glasses. He apparently did not favor bifocals as his non-president contemporary Benjamin Franklin did. Although the invention of bifocals is frequently attributed to Franklin, this claim has been plausibly debunked, as reported in our blog on the History of Eyeglasses.
Nevertheless, those Founding Fathers were a bunch of four-eyed geniuses.
Washington’s vice president and presidential successor, John Adams, was farsighted both politically (the Massachusetts Constitution he wrote became the model for the U.S. Constitution) and optically. He had basically the same prescription Washington did: +3.50 in his right eye, +3.59 in his left.
The history of presidential glasses goes fairly quiet until Lincoln, whose first purchase of eyeglasses has achieved the near-mythical status of Franklin’s bifocals. It’s been written that Lincoln bought his first pair of eyeglasses in 1856 in Bloomington, Illinois, for 37 ½ cents. (In today’s dollars, that would be around $10.00 – still more costly than the least expensive pair of Zennis!)
But scrupulous historians now believe that Lincoln’s first pair was purchased in the same state but in Springfield, in 1854. Two pairs of reading glasses confirmed to have been worn by Lincoln are in the Library of Congress. The first picture shows Lincoln wearing one of these pairs of glasses as he reads to his son Tad. The second shows the glasses he was wearing the night he made his ill-fated trip to Ford’s theater.
An example of Lincoln’s legendary wit – or at least whimsy – is reported in a story about one of his debates with senatorial opponent Stephen A. Douglas. Lincoln held up a copy of a speech Douglas gave the night before, disparaging Douglas’s remarks.
“Read it!” yelled a member of the audience. Lincoln replied:
“Gentlemen, reading from speeches is a very tedious business, particularly for an old man who has to put on spectacles, and more so if the man is so tall that he has to bend over to the light.”
The audience laughed, the newspapers reported the next day.
Early 20th century presidents, who wanted to display their technocrat cred, became more relaxed about being photographed in their glasses. Woodrow Wilson, formerly the president of Princeton, didn’t mind the egghead image his pince-nez glasses conveyed.
Herbert Hoover, who remained active in public life long after the last Hooverville shantytown gave way to Franklin Delano Roosevelt’s New Deal, appeared before the U.S. Senate in 1950 in a pair of glasses that would be considered a super cool geek-chic frame today:
In addition to suffering from polio, FDR was nearsighted and started wearing glasses as an undergraduate at Harvard in 1900. One of the pairs he wore was in the pince-nez style, intended to emulate his cousin Theodore.
Roosevelt’s last vice president, Harry Truman, who became president when Roosevelt passed away in 1945, favored translucent full-rim plastic frames, which are very popular today.
Truman had a strongly farsighted prescription. His glasses let him see up close, so he could easily tell where the buck stopped. When the buck stopped he could pick it up and put it in his pocket.
Dwight D. Eisenhower, who followed Truman into the White House, wore glasses although he was rarely photographed in them. When he was, you’d see him wearing the same style frame as Truman.
A poignant story emerges regarding Eisenhower’s successor, John F. Kennedy, who, with his wife, Jackie, brought a new sense of style to the presidency, no more so than in their choice of sunglasses.
A letter written by the American Optical Company’s director of public relations and advertising, H.P. Brigham, dated Nov. 19, 1963, recounts a visit by an eye doctor to the White House to examine JFK’s eyes. After fitting the president with a pair of reading glasses, the optician who accompanied the eye doctor showed Kennedy a pair of bifocals with no correction on the top half of the lens and a mild +1.00 on the bottom.
Kennedy was so taken with these bifocals that the optician was called back to the White House the next morning and asked to produce a pair of these glasses before the president’s press conference that very day.
They cranked out the glasses in roughly an hour and a half and got them to Kennedy in time for his press conference. He liked them so much he called back and asked for three more pairs.
At the bottom of the letter describing these events, a note was scrawled: “The day I received this Kennedy was shot.”
Kennedy’s vice president, Lyndon Baines Johnson, was the last U.S. President, so far, who was frequently photographed in glasses. Not unlike the split between guns and butter LBJ was unable to bridge, he favored two different styles of glasses. He wore the presidential style favored by Truman and Eisenhower: full-rim plastic translucent glasses.
But he also wore the brow line style that was very popular in the 1960s and is popular again now in the 2010s. LBJ didn’t have much else in common with civil rights leader Malcolm X, but they both liked the same type of glasses.
In the archives of the Johnson Library are two eyeglasses prescriptions for LBJ, one written in 1957, the other written in 1962. The two prescriptions are very close, but they represent a curiosity many eyeglasses wearers experience, when they see a prescription that calls for an astigmatism correction written with negative Cylinders (CYLs), as optometrists write it, and another one with positive CYLs, as ophthalmologists write it.
Whichever way you look at it, it still comes out the same.
Just like history.
Saturday, February, 8 2014 by Matthew Surrence
To celebrate Black History Month, Zenni honors iconic African Americans whose eyeglasses are an important part of their look.
No black American leader is more recognizable in their eyeglasses than the great civil and human rights activist and visionary El-Hajj Malik El-Shabazz, better known as Malcolm X. His familiar brow line glasses were very popular in the 1960s, and they are having a resurgence of popularity again today. Zenni has a similarly styled frame, 535425, or if you want to mix it up a bit, check out frame 599921 for a modernized update.
Spike Lee’s Malcolm X biopic is arguably the greatest film by this great American director who is also notable for the eyeglasses he sports. Lee always wears distinctive, and distinctively different frames, such as this full-rim plastic ombre (two-toned) pair, not unlike this Zenni frame, 286315,
…and this full-rim plastic tortoiseshell pair, similar to Zenni’s frame 230925.
Sticking with Malcolm X for a minute, not everyone knows that The Autobiography of Malcolm X was a collaboration between Malcolm X and Alex Haley, who went on to write the Pulitzer Prize-winning Roots, a monumental saga of slavery in the U.S. Because of this book and the miniseries that followed, Haley became a celebrated figure. He was always seen in a pair of wireframe aviator bifocals, similar to Zenni’s frame 418912.
A more recent biography of Malcolm X, the great American scholar Manning Marable’s Malcolm X: A Life of Reinvention, also won a Pulitzer Prize, which was awarded posthumously, since Marable passed away before the book’s publication. He favored classic round wireframe glasses, like Zenni’s frame 730015.
Staying on the Pulitzer Prize tip, poet Gwendolyn Brooks became the first African American to win a Pulitzer Prize, in 1950, for her second book of poetry, Annie Allen. One of her most celebrated lines comes from her poem, “Do not be afraid of no”: “It is brave to be involved, / To be not fearful to be unresolved.” Check her out in her glasses, very similar to Zenni’s 639512.
Since we’re looking at African American Pulitzer Prize winners, one of the most famous is the great novelist, poet, essayist, and activist Alice Walker, whose novel The Color Purple has had renewed life as a movie and Broadway musical. Walker always rocks her glasses, whether they’re rimless or wireframe, like Zenni’s frame 658021.
Finally, no one is more iconic in the American Civil Rights movement than activist Rosa Parks. Parks was a seamstress who was the secretary of the Montgomery, Alabama, chapter of the National Association for the Advancement of Colored People (NAACP) in December 1955, at the time she refused to give up her seat in the “colored” section of a bus to a white passenger when the white section was full. Parks’s action sparked the Montgomery Bus Boycott, one of the most important actions of the Civil Rights Movement, and she became an American icon. Parks was the first woman and second African American to lie in honor (lying in state is reserved for members of the military or elected American officials) in the U.S. Capitol Rotunda after she died in 2005. A statue of her is in the Capitol’s National Statuary Hall. As in life, her statue depicts Parks wearing an elegant pair of glasses, not unlike Zenni’s gold half-rim frame 448514.
Friday, February, 7 2014 by Matthew Surrence
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