Could it be Base Curve Issues???

**Now I See** · 09-29-2009, 01:08 PM

Hi guys and gals!

I have a patient that has been in to see me and is having a problem with her new RX. She says that when she looks down, up, or sideways then looks back she feels very "swimmy." She says it's not like that in her old RX.

Her old RX is:

OD +5.50 +0.75 x 007
OS +5.25 +0.50 x 002
Add +2.50

BC = 7
PD = 65.0/63.0
FT 28
I'm usure of exact material

Her new RX is:

OD +5.00 +0.25 x 020
OS +5.25 +0.75 x 172
Add +2.50

BC = 8
PD = 63.5/60.5
FT 28
I used a 1.60

My initial reaction is to remake them using a 7 base lens and matching the PD. I've adjusted the new frames to match the panto and faceform of the old glasses. I'd like your thoughts on this, please...:)

**optical24/7** · 09-29-2009, 01:13 PM

Is one aspheric and one not (old vs New)? Also, how far above the seg line are the OC's?

**Now I See** · 09-29-2009, 01:18 PM

Originally Posted by optical24/7

Is one aspheric and one not (old vs New)? Also, how far above the seg line are the OC's?

the oc's are at 6 above on both pair.

As far as aspheric....I did not make her old pair, but based on the curve of the lens, I would say that the old one is aspheric. I asked the lab upon my initial order if a FT28 1.60 was aspheric and was told yes, so (dummy me :hammer:) didn't even bother to check the base curve, until we had problems.

**Uilleann** · 09-29-2009, 03:35 PM

Heather,

It may more likely be the OCULAR curve on the BACK surface that is the culprit. 1.60 is not aspheric unless specified (or you and your lab have an aspheric understanding on EVERY lens you order above 1.49 already.) Also, and I'm sure I'm preaching to the choir here, bear in mind that often a patient will tell you their lenses don't feel right - when in fact it's the color or style of their new frame that is the real issue.

That being said, if I were designing those lenses, I would have chosen either a 1.67 or 1.60 as you did. Aspheric of course. A/R - period. And match the ocular curve first, then look at the base. Is the pt. used to wearing her glasses in an unusual manner such as far down her nose or abnormally high? What's her vertex like? What is her current best corrected VA? Any retinal pathology to be aware of? Glaucoma? MD? Diabetes out of good control?

Do you have the history you need? And any chance you can contact the original mfr. of her previous lenses for some greater info?

Brian~

**William Walker** · 10-11-2009, 06:20 PM

Are the dimensions of the frame fairly similiar?

**scriptfiller** · 10-12-2009, 03:02 PM

I would like to know how long she wore the old pair. We have had pats'. with similar RX's have the same experience when small changes in PD and RX have been made.

**Now I See** · 10-12-2009, 05:12 PM

Hi Scriptfiller, I'm not sure how long she had the old pr...

Since my initial post, I've remade these lenses for base curve, she liked them at first, now she's having a problem with what she calls a "blind spot", I'm still working on this....I'm sorry, I mistakenly started a new thread called "Pt says there's a blind spot". I'm not sure how to link to a thread. :o But, both threads are talking about the same person....see how confused this situation has me! :o