07/05/2015
Trouble Shooting - Progressive Lenses
You are all well aware of Progressive non-adoption cases.
I will discuss some of the point from my daily experience in favour of trouble shooting of progressive lens.
a) Help customer select the right FRAME.
Check the new frame curve (Base) and also check the customer old lens curve (Base). Try to maintain the same base curves or limit it to a difference of +/- 2 Base.
b) The nose bridge of the frame should be adjusted to sit properly on the customer’s nose.
c) Check the frame temple length which should be well bent at the back side of ear.
d) Frame horizontal & vertical size should not be more from the customer’s old frame. High plus/minus power will increase the thickness to maintain the p.d.
e) If customer is already wearing a big size frame and now choosing a new smaller frame make sure the right Progressive design is chosen. Make customer aware of the compromise he may have to make.
Refraction :
1) After the refraction is over, please check the old lens power (after marking the centre on the old lens) and the design/brand of progressive. Any major variation in power can lead to discomfort.
2) For progressive marking: In case of non-adaptation case, if there is a power change against the old power, the optometrist should repeat the refraction to verify the new power. In many cases, the customer is very comfortable with old power, and hence the same old power needs to be retained back.
Progressive Marking :
1) Mark the pupil centre( after wearing the frame) on the demo lens.
2) Verify it with PD meter and centration chart and mention the monocular PD also.
3) Once the pupil marking is completed, it should be cross checked with the progressive layout chart. (all progressive products have individual layout charts, and this should be strictly followed.)
4) Now measure the pupil height from the demo lens and select the progressive available with exact corridor, so that the distance and near part will not get cut off while edging.
Now measure the pupil height from the demo lens and select the progressive available with exact corridor, so that the distance and near part will not get cut off while edging.
Design :
1) Select a better design progressive than the customer’s old lens and also try to understand the wearing habit of the customer’s (importance distance/intermediate/near).
2) Extra short corridor prog : Frame vertical depth should be min 24mm - 28mm e.g. Nova XS & Ellipse
3) Short corridor prog : Frame vertical depth should be min 26mm to 30mm, e.g. Piccolo, Life XS & others
4) Regular corridor prog : Frame vertical depth should be 30mm above e.g. check from product catalogue.
Thickness :
1) Do not make any over commitment in terms of thickness.
2) For minus power according to index we maintain the minimum CT (+/- 0.2mm)
3) For plus powers mention the exact diameter. Please note the CT for each index is different for the same power.
4) In case of Supra and Rimless please mention the ET required at the specified Diameter.
5) Please refer the thickness chart.
Adjustment while Dispensing :
1) Adjustment of the frame is very essential at the time of dispensing to check if customer feels comfortable in distance, near and intermediate.
2) Adjustment plays a key role in progressive - We should check the adjustment in the customer’s old progressive specs.
3) Try to maintain the same pantoscopic tilt, as the pantoscopic tilt helps the customer in getting the near zone more closer to his eye and provides him a wider field of near vision.
4) In case of the new specs, if the same tilt has not been done, the customer will complain of smaller reading area.
