(upbeat music)
- Are you ready to play
America's hottest new game show
"Optical True? Or Optical False?"
The game show where we allow
our audience at home to play along.
True or false?
Lined bifocals are always distance and near.
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True or false?
The industry standard for the width
of a straight-top lined bifocal is 25 millimeters.
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true or false?
A single vision lens can be used for near work.
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True or false?
There is a lens so hideous
that it makes children and some adults cringe.
(bell dings)
True or false?
There are lenses that provide distance,
intermediate, and near that are not progressives.
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(intro music)
- Hello. I would like to welcome you
to the Laramy-K optician works training center
where today we are gonna look at single vision lenses,
lined bifocals, lined trifocals,
and we're gonna talk a little bit about round segments.
And well, that's what we're going to do today.
So let's just head on over to the whiteboard.
I'm a fan of starting at the beginning,
so let's start with single vision lenses.
Single vision, single, one, fixed.
A single vision lens
has no distinguishing features of any kind.
If I take this lens and I hold it up to the light
there are no laser etchings or no strange
(choir singing)
blend zones. There's nothing funky going on.
Everywhere I look on this lens it's the same.
Good telltale sign that it's a single vision lens.
If I have a packet like this or I'm filling an order
for a lens it can be very simple numbers.
Spheres, plus one, minus one, plus 2.50 spherical.
Or spheral cylinder, minus one,
minus 1.25, plus 0.75, minus 0.75.
That kind of stuff.
By all means, if you are completely
and totally brand new to this, you're at work,
well ask somebody to show you a single vision lens.
Single vision lenses are available in all possible powers,
all possible cylinders, all possible focal links,
all possible materials, and all different sizes.
Kind of important.
You have a single vision distance,
single vision intermediate and single near.
This is something that people tend
to get a little bit stuck on,
particularly when you're particularly new.
People always think of single vision
as being distance only for some reason
but of course they're available in anything
because they are a single focus, single purpose lens.
Computer only, distance only, near only,
sewing, those kinds of things.
Now, when I say single focus, remember that we have our eye
or we have accommodation and we have our brain.
So truly fixed your high power stuff.
Like maybe for almost like a magnifying glass
for super near work, pretty much just here.
But once you get out arms length a little further,
your accommodation, your brain takes over
and gives that lens a little bit more
range of focus and just perfect spot.
Single vision lenses are a-crazy, super cheap.
They are crazy, super easy to work with,
as you'll learn when you start doing finishing work,
there are billions with a B, probably far more likely,
trillions with a T or more than that
of these things out there in the world.
You've probably got a thousand
of them sitting on a shelf behind you, right this minute.
And these of course make up the stock single vision
uncut lenses that we do all that in-house work with.
Next up, we have aligned bifocals.
Bi, bi meaning two.
Two different distinct areas
of good crisp clear vision through a lens.
A lined bifocal can correct for all the refractive errors,
including ametropia, if you will,
with the added piece of presbyopia.
It is always going to be combined
a lens power, prescription, and an add.
Minus 1.50, minus 0.75, X is 92 with an add of two.
No add, no need for a bifocal.
There is nothing wrong
with a good old fashioned bifocal.
They can correct for plano with an add,
a prescription with an add,
a plano with a percentage of add,
a prescription with the percentage of add.
You can move this segment around.
These are incredibly versatile
and generally very inexpensive lenses to work with.
There are five videos that talk about
how to convert them to for different uses.
There was that one,
and that one,
that one,
that's a good one,
and that one too.
And if you look around out there enough
there are actually some stock planos
with specific add power ranges
that you can just keep in stock for emergencies.
There is a little bit of language
that goes with bifocals, lined bifocals.
ST is straight top.
FT is a flat top.
Every once in a while you'll see a D
if you turn the segment rotated around it looks like a D.
These are all interchangeable.
You'll hear different people use the different terms.
ST is the more common one you'll see.
Bifocals are measured, they're sized this way,
plugging the number.
You may find some 25s out there, somewhere
on the dusty back shelf of a lab somewhere they used to be.
28 is the industry standard.
And then there are 35 and 45 millimeter ones out there.
That makes for a very, very large area
of usable near or intermediate space.
Again, thinking about making different
unique things that give your customers a specialty lens.
We tend to think of bifocals as being distanced near
and I would strongly encourage you
not to think of them that way.
Think of how versatile they can actually be.
Look at those other videos that we've done.
The takeaway from straight top lined bifocals?
There is absolutely nothing wrong
with a good old bifocal.
As I've told you guys, I wear them.
I could wear any lens in the world.
I wear them. They are inexpensive.
They are easy to use. They're comfortable.
They're safe for driving.
You have customers that come in, repeated non-adapts,
people that don't like progressives,
they have some phobia, they don't work for them.
They want a really great hobby lens.
Make them one.
Be an optician.
Think about using the different styles, the different sizes,
moving that segment around, playing with your powers
to give your customer something truly unique that'll work.
That is what a lined bifocal looks like.
There is a closeup as well
of an actual pair of glasses with a lined bifocal in them.
Let's take a look at lined trifocals
which are pretty hard to come by these days.
We've got one, we've got two,
we've got three
lined trifocals, tri, three.
Three distinct areas of clear vision.
In this case, it's kind of all right
to think of distance intermediate and near.
They correct for all of the refractive errors
and what we will call later stage presbyopia
when you have that desperate need
for your full add power and an intermediate zone.
Any lens order, any lens power
is going to be that plus an add.
Minus 1.50, minus 0.75, add 92 with an add of two.
No add, no need for a bifocal or a trifocal.
A true trifocal design is a dated design.
They are, were (laughs) like it
tricky to work with.
The positioning of this vertically
in relationship to the eye you had, you know, on a good day
about a millimeter of play before it was too high
or too low, really kind of tricky things to work with.
Today very, very low need, very, very low demand
for these office progressives good progressives in general,
bifocals, changing the add power in a bifocal.
There's a lot of ways around needing a trifocal design.
Not that they're not out there
which is why we're going over this.
They are unlike a lined bifocal. They're not versatile.
You can't play much with the different powers behind it.
Different add powers, moving the segment around or anything.
They're not very forgiving in their design.
If you ever need to order a trifocal
or need to answer a question on a test
they are sized accordingly to A by B.
A being the height of the intermediate zone
and B the width of the segment itself.
There are two general sizes.
You have a 7 by 28 and an 8 by 35.
Just something you need to know about.
You, if you were starting out literally today as an optician
you may in fact never ever see one.
But if you do lay out and how to measure for one,
it was all covered on the optician work's website.
Three lenses to go.
We've got our round segment. It looks like that.
These are still used in occupational designs.
We have the video about that, that one there
and they're used for
I believe it's billiards, target shooting, archery.
Now the people that design occupational lenses
tend to play their card's a bit close
to their chest for obvious reasons.
So if you need an occupational, you need a round,
probably want to go to them.
Now, the other thing about a round, and I guarantee you
if you go on social media and mentioned a round segment,
someone will immediately jump in and say
"Those are used for pediatric ophthalmology."
Well, you know, I honestly believe that may be a myth
that we just keep repeating because we've heard it before.
I had been trying for 10 years to find someone
who would explain to me how and why
that is used in pediatric ophthalmology.
No one has ever stepped up to the plate.
If you, in fact, do know
then please email me so that we can teach others.
You have the executive bifocal, or as it's also known,
the Franklin, two lenses glued together.
I started this 30 plus years ago.
We actually used to see these once in a while.
I never ever had any trouble switching
a executive bifocal user to a straight top 35
or a straight top 45, your best choice.
I would strongly urge you to do that.
Last we have our executive trifocal.
That thing there.
Yeah, look, I don't hide it.
I hate those lenses for a wide variety of reasons.
However, I understand that they are still sold.
People still use them.
I would strongly encourage you not to do it
but if you must make or use an executive trifocal
use a great lab like Laramy-K.
We'll do a little prison thinning on it
giving you a slightly better profile,
a little thinner, a little bit lighter,
and maybe you'll get a little bit better cutout.
So there you have it.
We have single vision, lined bifocals, lined trifocals,
round segments, executive bifocals, and executive trifocals.
As always, thank you so much for watching.
If you are watching us on Facebook, please give us a like.
Watching me on YouTube, please go ahead
and hit that subscribe button down there in the corner.
Feel free to leave me a comment and make sure
that every single vision, lined bifocal, lined trifocal,
and maybe even a round segment comes from Laramy-K.
I will see you again next week.
(upbeat music)
False.
(coughs)
Yeah, that went well. (beep).