Question about ghost images in progressive lenses

[Uncle Fester]

You're busted. You are an old thread necrophiliac!

They never complain...

[drk]

You're busted. You are an old thread necrophiliac!

[Uncle Fester]

self delete

[cleyes]

Recheck refraction if problem nonexistent in previous glasses, that is a heck of a change in the cyl & axis, if not correct can cause mono diplopia or ghosting.

[KellyR]

A number of customers at my store suddenly saw "foggy rings" around lights and items at nightime. After many redos and re-checks, we realized that the blocking pads that we were using were staining the lenses. It was not visible to me or my colleagues but the customers swore it was there. I took my customer's glasses home with me and put them on while riding in the car at night and sure enough, there was the abberation they had all been talking about. This may help you, or may not, but it's a pretty good story :)

[One science]

It might a problem with the reflection. He should try to see how the things work ad how is the image in different lighten places.

[rdcoach5]

I had a similar problem that was hard to identify until I put it under a slit lamp. Then it was easy to see an area that looked like it had not been completely polished out before applying the AR.

[Robert Martellaro]

My client's refection problem was most likely due to a defective AR coat. A general inspection showed no waves or surface flaws in the lens or the coating. However, I could see a curved (lower in the middle, higher temporal and nasal, with about a 10cm radius) reflection across the lens, visible only in a dark room while wearing the glasses, with a single point light source held slightly off-center and aimed towards my eyes at arms length. The reflection was easy to see, distracting, and clearly unacceptable.

[marinaopt]

Thanks for the input. The lab manager is also going to analyze the front/back curves of his past and present lenses to see if that's the source of the problem. I'll let you know if we solve this.

[jimrask]

If it's a reflection, curving the frame might help a bit. (less flat frame ==> bend the temples of the frame towards the patients head ==> should reduce the reflection or at least change the angle in which it is reflected into the eye)

[drk]

Low-hanging fruit is "refractive problem".

[Robert Martellaro]

Help!

I have a patient that was in a five year old pair of Solamax polycarb progressive lenses (with ARC) with the following Rx:

OD -0.50-1.25 x 57
OS -1.25-1.00 x 113
+1.50 add

His Rx changed, and we put him into Physio CR-39 (he opted out of polycarb) with Alize ARC. His vision is fine at all distances except he experiences a "ghost" double image when viewing lights at night. It is a separate and distinct image directly above the primary image. This happens equally in each lens under both monocular and binocular conditions. Changing his viewing position through the progressives does not have any effect in lessening the ghost image.

This is his new rx:

OD +1.25 -2.50 x 080
OS +1.00 - 2.25 x 095
+02.25 add

Any ideas what the problem might be? I suspect internal reflections somehow induced by the CR-39 material, but I'm not sure.

Thanks in advance.

Early cataracts? Huge hyperopic shift, although I suspect that's over a 3-5 year span, and oblique astigmatism becoming strictly ATR.

I had a call yesterday with somewhat similar symptoms: a horizontal reflection across the middle of the lens. Somewhat similar scenario, a 1D hyperopic shift, no change in Add, although she was wearing her comp glasses for driving that had a +1.25 Add. Same PAL design. There may have been some mention of cataracts but this needs to be confirmed.

Age 55 Physician

Rx date 6-06 fitting date 6-07

General purpose (all lenses coated Super-Hi or Avance)

-5.25 DS
-4.75 DS
Add +2.00
Hoya iD 1.70

Rx and fitting date 4-09

-5.00 DS
-4.75 DS
Add+2.25

Computer/desk glasses

-4.00
-3.75
Add +1.25
Auto 2 fixed 18mm

1-10 Complained of poor near vision with comp glasses.

Rx and fitting date 02-10

-4.25 DS
-3.75 DS
Add +2.00

Updated comp/desk glasses

-3.25
-2.75
Add +1.00
Auto 2 fixed 18mm 1.60

General purpose

-4.25
-3.75
Add +2.00
Physio 1.60

This is the pair that has a horizontal reflection across the middle of the lenses on the distance gaze at night.

My plan is to have her come in after dark, shut down the office lights, and trial frame looking out my office window at traffic and street lights, and inspect the lens for flaws. I suspect a fabrication error or over-plussed. I hope it's that easy. I'll post the results when she comes in.

[Uncle Fester]

Give this trick a try...

When the patient is experiencing the ghost image see if it's a reflection issue by having them block the light by holding their hands above their forehead (like a visor) then both hands on each side then from below. It should help understand where the light causing the problem is coming from (if it is a reflection) so you can try to adjust/fix accordingly.

[Darryl Meister]

Odd change in prescription???

I would verify the amount of prism-thinning in the lenses. For low-powered lenses in particular, prism-thinning can shift internal reflections away from the original light sources that would otherwise obscure the reflections. This renders these reflections more visible to observers in some cases.

Differences in prism-thinning between two pairs of otherwise identical progressive lenses may therefore influence how readily ghost images are noticed by the wearer. Of course, the application of an anti-reflection coating will eliminate this problem entirely.

[YrahG]

Monocular and Binocular means that we can pretty much rule out a prism imbalance (of course you always check the PRP on a PAL from the lab anyway). As for ghost images if the frame is large enough you may be getting rays from behind that are reflecting off the back surface of the lens into the eye. The problem seems to be that the reflected images focal power is close to or equal to the focal power of the lens so you have two images coming into focus. You need to change the reflected images focal power and more than likely you need to change the back curve to do that. You can try changing the lens to one with a different back curve to try and offset this. You have already done everything else AR and low reflectance form the material means the intensity of any reflections are being managed properly. Another approach would be an index change which would modify the back curve of the lens.