Patient has double vision!?

**audreyp** · 03-26-2010, 10:25 AM

I have a patient with the follong RX:

OD: -3.50 +1.00 x 180
OS: -1.00 +1.50 x 180

SV lenses

I have had plenty of patients in my day do just fine with a RX with 3 diopters difference, but this patient has seen "double" with every pair of glasses he has from other opticals. In the interest of getting it right, I would like to get some opinions about what may help him.

He says when he looks straight through the lens it is "okay", but if he tilts his head up or down he sees two of everything he focuses on (i know, i know ... "well, stop doing that!") My first instinct is was that the BCs were too different for comfort, but his current pair has the correct RX with 4B lenses both. He has tried a SV slab off already ... whatever help that was supposed to be? Anyone seen this before? Would an aspheric design help? I am at a loss. Thanks.

ap

**CME4SPECS** · 03-26-2010, 11:34 AM

Of course there will be double vision the further he gets off center, due to the imbalance. I have a customer with similar rx and he can not tolerate the lenses without a slab-off. I'd put a slab-off on the lens and at least give him better vision at near.

**braheem24** · 03-26-2010, 11:49 AM

Fit with a very small "B" and you wont have to tell him not to do it.

It's either that or *slap* a -3.00 CL on his right eye and correct everything else with glasses.

If you go the *slapping* route make sure to over-refract as some of the cyl my increase or decrease if any of it is corneal astigmatism.

Disclaimer: all *slapping* must be done under the direct or e-supervision of a trained professional and may be attempted at home for convenience.

**drk** · 03-26-2010, 12:02 PM

Braheem is pretty close. I'd simply fit soft torics.
(P.S. These days, you don't have to worry about cylinder "masking". You'll never see it.)

**audreyp** · 03-26-2010, 12:03 PM

I think the recommendation for the small "b" measurement is sound advice. Thanks. I will also sternly shake my pointer finger at him while reminding him to "quit doing that".

and of course ... severe dry eye.

**drk** · 03-26-2010, 12:06 PM

It could be an indication for surface ablation, as well.

**Robert Martellaro** · 03-26-2010, 01:24 PM

Originally Posted by audreyp

I have a patient with the follong RX:

OD: -3.50 +1.00 x 180
OS: -1.00 +1.50 x 180

SV lenses

I have had plenty of patients in my day do just fine with a RX with 3 diopters difference, but this patient has seen "double" with every pair of glasses he has from other opticals. In the interest of getting it right, I would like to get some opinions about what may help him.

He says when he looks straight through the lens it is "okay", but if he tilts his head up or down he sees two of everything he focuses on (i know, i know ... "well, stop doing that!") My first instinct is was that the BCs were too different for comfort, but his current pair has the correct RX with 4B lenses both. He has tried a SV slab off already ... whatever help that was supposed to be? Anyone seen this before? Would an aspheric design help? I am at a loss. Thanks.

ap

That's certainly not normal. I'm not sure what our vertical fusional reserves are, but they should be at least 3^ for most healthy eyes. With this Rx, that should allow an up or down gaze of about 10mm without breaking fusion. I would get some input from the prescribing doctor.

Normal fitting procedures would be to fit the OC level with the pupil center on the distance gaze, fit as close to the eyes as possible, and instruct the wearer to read with the book held somewhat higher than normal.

**Fezz** · 03-26-2010, 01:55 PM

Tumor?

**braheem24** · 03-26-2010, 02:12 PM

Reserves are less when you're inducing the prism through head movement. Most mens frames are ~30+ B measurement which would make prism closer to the 4.5 range.

**WFruit** · 03-26-2010, 02:14 PM

Just because plenty of patients before haven't had an issue doesn't mean you've got one that's more sensitive than all the others. Too often we feel that if most other patients haven't had an issue, then all patients won't have an issue.

Single Vision slab off is not the answer, however, since he has issues moving both up and down (unless you want to do a double slab off with a non-prism ribbon in the center....). Small "B" is a good idea, as well as double checking all of his old measurements.

**drk** · 03-26-2010, 10:23 PM

It's naaauuuutttt a tuuuummmaaaaahhhhhh. (Arnold).

RM yes, you're right, not normal, but yeah you'll see some variation in fusion quality in oddballs. Wfruit is probably right.

**fjpod** · 03-27-2010, 03:58 AM

This patient may have limited vertical (and/or horizontal) fusional ranges. They should also be checked for latent hyperopia with cycloplegia. They should also be observed for gait, torticollis and head tilt. Careful cover testing should also be done in all positions of gaze. this patient could benefit from optometric vision therapy. Sometimes there is more to a refraction than the Rx.

**jimrask** · 03-27-2010, 03:02 PM

You could put him in Aspheric lenses. Make sure to put the OC of the lens 4 mm below the center of the pupil. If the double vision is due to the anisometropia (the difference in image size is too big for the brain to fuse both images together), I really would suggest adapting toric contact lenses (soft or hard, need to see more data before deciding ==> severe dry eye isn't that much of an obstacle in the newest generation of RGP lenses since they have extremely high Dk values and the materials are more comfy on the eye then soft lenses).