Base Curve / PD Remake Rimless Drill Mount

[b0mbsquad1]

Hello Folks,

We had a pair of rimless drill mount glasses that were remade since the PD was incorrect and at that time the BC was 5. We requested to match the base curve to the old glasses which was 3.5 to help adapt. Prescription was only bumped up .25 - .50 and astigmatism was left unchanged.

The lab dispensed it in a BC of 6 instead of the base curve that was requested of 3.5 or original BC of 5. The new lenses are causing issues where the center of the lens is not as sharp or focused as when you view from the left part of the lens (have to move the glasses to the right for better vision in the left eye or move the glasses left for slightly better vision in the right eye). Text is not as sharp/focused in the left eye and tends to be bigger/blurry when compared to how crisp and clean the right eye is. Road signs that state turn ONLY the ONLY is not clear in the left eye compared to the right eye.

Left eye is causing issues and right eye is acceptable but gets better with a slight shift. Would this still be PD, BC, or face form (wrap). Thanks for your help.

Rimless Drill Mount
1.67 Single Vision SVextreme Unity Transition / AR - Digital

Old Prescription

OD: -3.00 -1.25 005
OS: -3.75 -1.25 170

New Prescription
OD: -3.50 -1.25 005
OS: -4.00 -1.25 170

Regards,
b0mbsquad

[medicalretina]

blessings brother...
it sounds like a wave on the lens...possibly surfaced too thin...plus it has a very high toric curvature prone to cause excessive heat on the cylinder machines while fining and polishing...i would definitely have them remade with a flatter curvature...i would not go any steeper than 4bc with that prescription....spot the lenses at the opitical centers on lensometer then check the thickness on the optical centers..i can almost guarantee left lens too thin...and also move around on the lensometer and look for waves on the lens.....aberrations...

much divine love

william

[b0mbsquad1]

blessings brother...
it sounds like a wave on the lens...possibly surfaced too thin...plus it has a very high toric curvature prone to cause excessive heat on the cylinder machines while fining and polishing...i would definitely have them remade with a flatter curvature...i would not go any steeper than 4bc with that prescription....spot the lenses at the opitical centers on lensometer then check the thickness on the optical centers..i can almost guarantee left lens too thin...and also move around on the lensometer and look for waves on the lens.....aberrations...

much divine love

william

Got it, thanks. I can see on the nasal edges of the lenses the letter T67 and SV inscribed on them and letter U on the outer edge of the lenses. Do you know if this is how the lenses are made or were cut?

[b0mbsquad1]

Here is the detailed information on the different lens types. The current lens is SVxtreme which delivers a compensated Rx. Do you think the wrap along with compensated Rx is causing issues in the left eye?

https://www.vspopticsgroup.com/unity/unity-single-vision-lenses.html

https://www.vspopticsgroup.com/pdf/unity-single-vision-sell-sheet.pdf

Unity SVx
The original single vision lens solution, Unity SVx, uses sophisticated lens design technology for exceptional performance for single vision lens wearers.

Unity SVxtra
Unity SVxtra offers position-of-wear precision, delivering a compensated Rx to give your patients even greater customization and clarity by compensating for frame wrap, pantoscopic tilt and back-vertex distance. Unity SVxtra delivers a visual experience customized to each patient's visual needs and frame style. Both Unity SVx and Unity SVxtra lenses are excellent choices for your single vision patients with moderate to greater cylinder power.

Unity SVxtreme
Unity SVxtreme is the ideal lens choice for patients wanting Unity performance without limiting their choices for wrap frames. Unity SVxtreme decreases peripheral distortion and increases clarity in line-of-sight. Like SVxtra, SVxtreme incorporates position-of-wear measurements for added customization. It's a simple solution for all of your patients' daily activities.

The Unity Precision Difference
Freeform technology uses state-of-the-art lens processing equipment and advanced digital lens designs to deliver the most precisely crafted prescription possible. Customized Unity lenses can be created to address your patients' specific visual requirements, within 1/100 of a diopter. The ease of adaptation and high satisfaction your patients experience is a result of a quality verification process with every Unity lens produced. To ensure the lens design is exactly what the doctor and lab intended, each lens is digitally mapped. This extra step ensures precision and accuracy with every Unity lens.

Base Curve Elimination
Unlike conventional single vision lenses, the Unity freeform design allows customization of each prescription to account for optical variations with base curves and frame sizes. With traditional processing, there is only one prescription, without cylinder correction that's ideal for any given base curve. As you introduce correction for astigmatism, only freeform optimization can precisely correct optical error. Unity SVx lenses deliver superior clarity for each unique prescription.

[Tallboy]

Are you sure it is the SVxtreme? That lens is only available in a 6 base or 8 base... might be your problem. Its usually used for wrap jobs, or extremely high plus.

You probably meant to order (or say here?) SvXtra, which is also an IOT SV compensated lens. Pretty good stuff. That lens design is available on usual base curve choices.

Either way they should have contacted you to say that the base curve you chose was not a viable option on the SVxtreme

[drk]

What Tallboy says.

Is this an ophthalmic frame? There would be no reason to do a faceform compensation. (Especially with that Rx.)

I think this is a case of "the bots"...no human has used their brain in this job.

I would scrap the individualization approach until I understood what VSP's protocols and products are. (I doubt many at the VSP labs understand it, either.)

But if you do figure out their products, you can see that in your case, probably the only feature that matters is the atoricity that the customization provides. (Not the vertex distance, or frame wrap, or 1/100th of a diopter marketing garbage.)

[drk]

Addendum:

What's more, the "p.d." problem was probably due to an automatic outset for wrap compensation.

[b0mbsquad1]

Are you sure it is the SVxtreme? That lens is only available in a 6 base or 8 base... might be your problem. Its usually used for wrap jobs, or extremely high plus.

You probably meant to order (or say here?) SvXtra, which is also an IOT SV compensated lens. Pretty good stuff. That lens design is available on usual base curve choices.

Either way they should have contacted you to say that the base curve you chose was not a viable option on the SVxtreme

Please see the attached image which provides a detailed breakdown of what was requested. The lens that was chosen was SVextreme and was too aggressive for the frames or Rx. I don't like the fact that SVextra or SVextreme end up being a compensated lens. I might make a request to provide the basic Unity SVx.

What Tallboy says.

Is this an ophthalmic frame? There would be no reason to do a faceform compensation. (Especially with that Rx.)

I think this is a case of "the bots"...no human has used their brain in this job.

I would scrap the individualization approach until I understood what VSP's protocols and products are. (I doubt many at the VSP labs understand it, either.)

But if you do figure out their products, you can see that in your case, probably the only feature that matters is the atoricity that the customization provides. (Not the vertex distance, or frame wrap, or 1/100th of a diopter marketing garbage.)

I agree that there was probably no humans involved in the process at the lab and the incorrect lens was used for the frame/Rx. I don't like the fact that individualization approach is causing more issues and resulting in non-adapt.

On paper all the customization sounds awesome but in reality it is not applied properly and ends up resulting in poor vision. I guess we might need to take the KISS approach with this lab.

Addendum:

What's more, the "p.d." problem was probably due to an automatic outset for wrap compensation.

Agreed that the PD issue was probably just the automatic outset due to wrap compensation. This is causing issues with vision and results is strain/headache.

What do you recommend is the best option for High Index lens to match the old base curve? Please see below for the frames that will be used for this order.

[Tallboy]

No offense but you don't sound like you have the slightest idea what you are talking about. Do you have a supervisor or senior optician you can talk to?

I am mortified that you are working somewhere and asking the questions you are asking.

Maybe call your Unity Rep and see if they can send you some training materials or you can take some CEs on basic optics?

[Barry Santini]

In a conventional Rx, you learn NOTHING about the true BV state of a person's eyes. Therefore, PD metrics mean NOTHING!!!!!

B

[Jason H]

Base curve is a cop-out most times - especially with free form digital. I'd ask for more specific complaints and try to diagnose it from there.

[drk]

Harsh people. Need more coffee.

1. Cool frame. Tag is expensive.

2. As Jason H says, we obsess with base curve. It rarely will cause a problem, except maybe higher plus patients where they can flip from one steepish BC to the next steeper one with a minimal increase in power. All the minus powers have big batches of flat curves. (Look at a Tscherning Ellipse or some chart. I bet Tallboy has one tattooed on his bicep.)

3. As you are guessing, each index has it's own base curve idea for a given power (I think that's right). What's more, when we use individualized optics, then I think the front curve used becomes even murkier, yet. We just can't worry about it too much, or we would be frazzled all the time.

[drk]

M.O.

I was given the mental picture of a front-surface minus aspheric being like a frisbee...the periphery gets curvier.

What mental picture can I use for a back-surface minus aspheric? A super-blended lenticular-like periphery?

[Tallboy]

I'm sorry I came off like an ***. I just had flashbacks to talking with any one of numerous people obsessing over their base curve because their opthamologist wrote Use Same Base Curve on all of their RXs.

Sorry bombsquad we are all here to learn as opticians...

[uncut]

M.O.

I was given the mental picture of a front-surface minus aspheric being like a frisbee...the periphery gets curvier.

What mental picture can I use for a back-surface minus aspheric? A super-blended lenticular-like periphery?

Perhaps a stealth myodisc?