03-Mar-08

“Zoomerang” Internet Questionnaire on power measurement practices

– Analysis of response by Optician Association of America (OAA)

Feb 2008 data

03-Mar-08Dick Whitney (CZV) / Joe Dezenzo (Luxottica Retail)

Optician Association of America (OAA) “Zoomerang” response to Questions on power measurement practices –

Dick Whitney (CZV) / Joe Dezenzo (Luxottica Retail)

Joe worked with the Opticians Association of America (OAA) and got their agreement to participate in an Internet “Zoomerang” Survey. Their cooperation is most appreciated.

At the Sept. 2007 ANSI Z80.1 meeting, the topic of ANSI /ISO power measurement practices and tolerances use was discussed

Dick Whitney agreed to work on a questionnaire to determine industry practices in power measurement. Joe Dezenzo (Luxottica Retail) volunteered to assist.In Dec 2007, Dick drafted a set of questions and sent to Joe; Joe refined them and pursued on line “Zoomerang” method.



a) Automatic Focimeter /Lensometerb) Manual Focusing Lensometer– Scale outputc) Manual Focusing Lensometer – digital outputd) Both Automated and manual focusing

1.) What type of power measurement equipment is used in your facility?:

2.) What cyl mode is used for display?

a) Minus cyl (-)b) Plus cyl (+)

3.) If digital output, what increment readout (rounding) is used?

a) noneb) 0.12c) 0.25d) Othere) Don’t know

The following 10 questions were asked of the OAA members:



a) Internal / company specificationsb) ANSI Z80.1c) ISO 8980d) Other

4.) What Standards or specifications do you use for RX power verification / acceptance?

5.) Where are these Standards or Specs located?

a) Next to the Lensometerb) In a drawerc) Not sured) Don’t have them

6.) How long have you used these tolerances?

a) Less than 5 years

b) Six to ten yearsc) More than 10

years



7.) What action(s) might you do you use if the lens has been found to be out of tolerance for power?

a) Re-measure a second time on same instrument without moving lensb) Re-measure a second time on same instrument, moving lensc) Measure on another instrumentd) Reject lens without re-measurement

*8.) Does your facility use a computer system to determine if the lens meets power tolerances?

a) Yesb) No



9.) Question asked: Do you tolerance the sphere and cyl meridians individually or the powers when checking the cyl?

a) Sphere and Cyl

b.) Sphere / Cyl Meridians

c.) Don’t know

=What is displayed on Automated Units and written in Rx’s

Both principle focus powers, cyl must be computed for manual focusing, cyl meridian must be computed for automated

= Perhaps the most honest answer!



Question 10

Prescribed Rx: +0.25=-3.25 x 103 Measured Rx: +0.37= -3.18 x 103

Would you pass or fail this lens for power?

a) Passb) Fail



Wholesale Lab

Retail Chain

O.D. Office

M.D. Office

Private Optician

Other, please specify

Let’s review the outcome!

Number of OAA participants= 331 in the following categories:

4% 20% 21% 18% 29% 8%



OAA (Opticians Assoc. of America) Reponse to Feb08 Zoomerang Questions

0%10%20%30%40%50%60%70%

AutomaticLensometer

Manual FocusingLensometer-Scale

output

Manual FocusingLensometer-Digital

output

Both Automatic andManual Focusing

Question 1- Type of Instrument

Question 1 Response – Type of Instrument

Automatic 19%

Manually focusing 65%

Manually focusing digital 3%

Both 32%




0%20%40%60%80%

100%

Minus cyl (-) Plus cyl (-)

Question 2- Cyl Mode output used

Minus cyl (-) 82%

Plus cyl (-) 18%

Question 2: Cyl Mode output (where it applies)




0%

10%

20%

30%

40%

None 0.12 0.25 Don't know Other

Question 3 - Instrument rounding used

Question 3: Increment rounding (where it applies)

None 27%

0.12 35%

0.25 23%

Don't know 7%

Other 8%




0%20%40%60%80%

100%

Internal / CoSpecif ications

ANSI Z80.1 ISO 8980

Question 4- What Standard s or Specs do you use?

Question 4: What Standards / Specs do you use?

Internal / Co Specifications 14%

ANSI Z80.1 83%

ISO 8980 0%

Other 3%




0%10%20%30%40%50%60%70%80%

Next to theLensometer

In a draw er Not sure Do not have any onsite

Question 5- Where do you keep the Standards / Specs that you use?

Question 5: Where do you keep your Specs?

Next to the Lensometer 70%

In a drawer 19%

Not sure 5%

Do not have any on site 7%




0%

20%

40%

60%

80%

Less than five years Six to ten years More than ten years Don't know

Question 6- When was the last time you updated your tolerances?

Question 6: When did you last update your Specs?

Less than five years 72%

Six to ten years 8%

More than ten years 3%

Don't know 17%




0%10%20%30%40%50%60%

Re-measure onsame

instrumentw ithout moving

lens

Re-measure onsame

instrument,moving lens

Measure onanother

instrument

Reject lensw ithout re-

measurement

Other, pleaseexplain

Question 7- What Action(s) might you use if the lens is found out of tolerance?

Question 7: What do you do when lens is out for power?

Re-measure on same instrument without moving lens 33%

Re-measure on same instrument, moving lens 57%

Measure on another instrument 46%

Reject lens without re-measurement 13%

Other, please explain 15%




0%

20%

40%

60%

80%

100%

Yes No

Question 8- Do you use a computer to determine if the lens meets your power tolerances?

* Question 8: Do you use a computer to see if the lens meets your power tolerances?

Yes 7%

No93

%



9.) Intended question: Do you tolerance both the sphere and cyl meridians along with the cyl, or just sphere and cylinder?

Sphere image (equally focused lines)

<= Meridian 1 Image

Meridian 2 Image

Just for review:

Cyl (written in Rx and displayed on automated focimeters) = Sum of Mer 1 and

Mer 2 Measured values; it does not have an image!




0%

20%

40%

60%

80%

100%

Sphere and Cyl separate Both Sphere/CylMeridians

Don't know

Question 9- What Meridians do you tolerance?

Question 9: What meridians / values do you tolerance?

Sphere and Cyl separate 76%

Both Sphere/Cyl Meridians 22%

Don't know 2%




0%

20%

40%

60%

80%

Question 10- Would you pass or fail the RX?

Series1 67% 33%

Pass Fail

Prescribed Rx:+0.25 -3.25 Measured Rx: +0.37 -3.18

Question 10:

Prescribed Rx: +0.25=-3.25 x 103 Measured Rx: +0.37= -3.18 x 103

Would you pass or fail this lens for power?

So which answer is correct?

The Answer is….




0%

20%

40%

60%

80%

Question 10- Would you pass or fail the RX?

Series1 67% 33%

Pass Fail

Prescribed Rx:+0.25 -3.25 Measured Rx: +0.37 -3.18

Question 10: Prescribed Rx: +0.25=-3.25 x 103 Measured Rx: +0.37= -3.18 x 103

It depends on what tolerances / specifications you are using…

For those 67% who would pass the lens, they are using “common US Industry practice” and neither ANSI 1995 / 2005 or ISO 8980…

Record prescribed RX: OD: +.25 = -3.25 x 103

Measure fabricated RX:

Is sphere error > .13? Absolute difference is .12, therefore sphere power acceptable Is cyl error > .13? Absolute difference is .07 and axis is 103 as prescribed, cyl is

acceptable.

Therefore, the lens Passes for power inspection

Here is how “Common US Industry practice” would have passed the lens:

Here is how one might fail the lens using ANSI standards since 1995 (~ISO)

1 Record desired RX / Transpose if necessary 0.25 -3.25

Step Sphere Cyl

2 Measure lens / record reading 0.37 -3.18

3 Look up tolerance on Sphere power (Meridian 1) 0.12

4 Compute abs difference for sphere reading 0.125 Pass / Fail for sphere power error Pass

6 Look up tolerance on Cyl 0.12

7 Compute abs difference for Cyl 0.07

8 Pass / Fail for cyl Pass

9 Compute intended cylinder meridian power from sph / cyl -3.0010 Compute measured cylinder meridian power from sph / cyl -2.81

11 Look up tolerance on Cylinder Mer power (Meridian 2) 0.12

12 Compute abs difference for Cyl Mer reading 0.19

13 Pass / Fail for cyl meridian power error Fail

The lens fails ISO tolerances for a power that is not displayed on the Focimeter, but must be calculated. It is also a failure to ANSI Z80.1 because of strongest meridian error, but few labs ever apply this. It passes the common practice of tolerancing the sphere and cyl.

The ANSI /ISO method can only practically be used using a computerto calculate pass fail as it relies on tables like this:

Recall that 93% of respondents did not use a computer at inspection.

Could you figure the pass fail without a computer?

ANSI / ISO table

From their answer to question 10, 67% did not use the ANSI /ISO Method

even though 83% said they did!



Thanks to the OAA for their cooperation!

It is proposed that other organizations take part in a similar study. Any comments or suggestions?


Documents

03-Mar-08