of let's learn how to use the lensmeter.

(upbeat music)

From this point forward, in this particular series,

you're gonna be working with our Learn the Lensmeter kit.

The kit is available online at the OpticianWorks website.

You'll get a box.

Inside the box, there are gonna be

nine pieces and this booklet.

The booklet starts with a review of what's in the kit.

It'll give you some tips on using it.

It'll give you two single-vision lenses

where you'll just learn how to move a lens around

and what you see when you look in the lensmeter.

You can start learning how to use the power drum.

Then we'll jump into some job order forms

and actually look at a single-vision lens,

a line bifocal, and a progressive, loose lenses.

Then we'll get into mounted pairs

where we were doin' some verification,

final inspection kind of work.

And then last, we'll wrap up with three examples

of actual layout work for those of you

that are interested in finishing.

We're gonna do a really brief whiteboard session

because honestly, if you've never seen

what's inside the lensmeter,

you've never worked with a lens, first time,

it really helps us to kinda get the big picture of things.

Two housekeeping items before we move on.

Remember that a manual lensmeter is a subjective tool.

As long as there is a human involved

and I can turn knobs and I can turn power drums,

it's a little subjective.

You're gonna get in those situations

when you get into your first job

and you're gonna have Bob the optician come say,

oh, no, no, that's off power,

and then Sue's gonna come in behind him, go,

no, it's not, it's fine, just keep going.

There is a certain amount of subjective

measure to a manual lensmeter.

So, just always keep that in the back of your mind.

Number two I already talked about,

if you go for your practical exam,

you've been preparing, it's stressful,

it costs a lotta money, you drove 65 miles to get there,

you're taking your practical exam,

you wanna get your optician's license,

if you do not do your focus for individual use

before you jump into your layout or verification work,

you will fail, don't do that.

Make sure you watch the video before this,

so you know how to do that and do it before you begin.

There are four things we're gonna talk about.

We're gonna talk about the reticle.

We're gonna talk about sphere lines.

We're gonna talk about cylinder lines.

And we're gonna talk about the target.

The reticle you've already seen

when you watched that first video piece,

and it's a grid of three, four, five concentric circles.

It does depend on the lensmeter.

They don't move.

They'll always be in the same position

when you look into the lensmeter.

They're not gonna shift up or down.

It's a fixed graph.

The one line here that goes across, you can move

when you move the chrome knurled sleeve,

this will swing around,

but it can only move in the zero 180 plane.

It doesn't move anywhere in this direction.

If you go ahead, turn on your lensmeter,

put your eye up against the eye cup,

rotate the power drum till you see that pattern.

You should see three thin lines and three thick lines.

They should be in focus and if your lensmeter

is calibrated correctly, everything was working right,

your PCD is in the correct position,

this center grid pattern,

this perfect center point

should be in the perfect center of this smallest ring,

which I like to call the target

because your goal 99% of the time

is going to be to get this on target in here,

perfectly split on these lines,

perfectly split on that line.

Your three thin lines of this pattern are your sphere lines.

They indicate the sphere power

of the lens that you're reading.

The three bars or three thicker lines

are your cylinder lines.

They are going to be in focus when you are

at the full power of the combination

of the sphere and the cylinder value together.

Unlike the reticle, which is fixed,

if I have a lens in the lensmeter, as I move

the lens around, this is gonna move all over the place.

This can go anywhere.

It can also rotate around.

If you take your axis wheel right now

and spin the axis wheel, you'll see this spin around.

By pulling back my lens holder a little bit,

grabbing my lens and moving it around,

this will shift within here.

We're gonna look at that in just a minute with lens one,

so that you have an idea what I'm talking about.

Last point I wanna make before

we go to actually using the lensmeter.

There are times if you have a spherocylinder lens,

any lens with a sphere, a cylinder, and axis,

where only the sphere power lines will be in focus.

You're only gonna have those three

beautiful, crisp, straight, thin lines.

You're gonna rotate your power drum or to

depending on plus or minus cylinder,

the value of your cylinder.

And then you're gonna get your cylinder bars in focus.

You may be able to see them kinda in the background,

a little hazy, out of focus,

but they will not be crisp and clear.

All right, lens one, it says, and you can read along

because you have this in your hand as well,

is a basic loose single-vision spherical lens.

A spherical lens has the same power across the entire lens.

We're gonna use lens one to learn to identify

what we will see inside the lensmeter

when you look through the eye piece.

So, let's grab lens one, let's unwrap lens one,

and somewhere on that lens if you look,

you'll see an engraved mark for one.

So, make sure that somebody put them right,

back in the right bags.

You should already have watched the previous video.

You should already have the lensmeter set up

so it's comfortable for you.

It should already be dialed in to your particular eyesight.

I'm gonna take my number one lens here.

I'm gonna rest it against the lens top,

and I'm gonna slowly and gently release

my lens holder against the front of the lens.

To get started, your power drum can be anywhere.

I do want your axis wheel to be at zero.

So, rotate that around if you need to,

so that you're reading, you're looking through that little

magnifying glass and you've got a nice, straight zero.

That will make sure that what you're seeing

and what I'm talking about are both the same.

What we're gonna do here is use this lens

to practice two things.

One is simply getting the lens in focus

and two is getting that grid pattern,

the cross over between the cylinder and the sphere lines

in that perfect center of the target.

We've got a 150 lens here.

What I did was give you just enough power

that you can move the lens around, then see movement.

As power goes up, getting it centered and getting it perfect

becomes more and more difficult.

Wait to you get to your first minus seven or plus seven.

It's gonna be a whole lot harder.

That's why I want you to practice, practice, practice.

That's all this, number one, lens number one,

this first lesson is about.

Let's practice just bringing the lens into focus.

Look in through the eye piece, your center cross

where the sphere and the cylinder lines come together.

It may be displaced.

It may not be perfectly centered.

It might be up and over or down, it's all right.

Let's just practice bringing it into focus.

Rest your eye on the eye piece

and simply rotate the power drum towards you,

away from you, towards you, and you will see eventually

where that lens is gonna come in to focus.

And simply practice that.

Practice so you get a feel for the drum.

Watch what happens when you're looking inside.

See how the lines come into focus.

Go back out, come back in.

Practice, practice.

And one more time, let's bring that into focus and stop.

To bring a lens into target,

I have no idea where your lens is in your lensmeter,

so I can't predict perfectly what you're gonna see,

but it's gonna be something pretty close

to what you see here on the screen.

You're gonna take your lens and you're gonna be holding it

like this and this is kind of important because it

allows you to move the lens around in multiple directions.

You're not gonna take your lens holder off.

You're simply gonna use your finger

to relive a little bit of the tension that the lens holder

is placing against the lens and the lens stop.

Looking inside, I'm gonna take that little bit

of tension off and I am going to move my lens around.

Just get used to how that feels.

Move that lens around.

Eventually, what you're gonna wanna do is start practicing

getting that lens on center in the cross hairs.

You actually want to be going for the center.

You wanna split that thinnest center sphere line.

You wanna split the thicker center cylinder line.

When you have those split, you are on target,

and this lens could be marked for finishing work or layout.

That's all I want you to do with lens one.

Don't get carried away, but don't quit here either.

I do want you to go back to this

three, four, five times throughout the day,

practice bringing that lens in and out of focus,

practice bringing it into center,

and even start throwin' some dots on there.

Clean it off, start over, do it again.

That's it for lens one.

Next time, we'll get into a spherocylinder lens

where everything gets a little bit more complex

and we start playing with out axis wheel as well.