Ok, We have a patient that has keratoconus and presenting with a script of
-1.50 -1.00 x 145
-10.75 -1.00 x 090
Currently a standard 1.67 lens SV lens design. What would you guys/gals recommend?
major script question
Ok, We have a patient that has keratoconus and presenting with a script of
-1.50 -1.00 x 145
-10.75 -1.00 x 090
Currently a standard 1.67 lens SV lens design. What would you guys/gals recommend?
And the doc didnt put any prism in the RX? But if the patient is good with what he had before at about the same RX, Id stick with high index or even go with trivex and either with AR. That seems way past what the docs say about the ability of an individual to resolve the difference in the image without compensation.
I wouldn't make them...unless the patient was wearing something similar to this before, without symptoms. I don't know that prism is going to help here. Even if the patient can achieve close to 20/20 in the left eye with this Rx. It will create more anisokonic symptoms than the patient will bear.
There's not much more that can be done except some additional thinning with 1.74 index and/or free-form lenticularization in the left for cosmetic reasons. Use atoric POW optimized Trivex in the right.Originally Posted by Eyedentity3
http://kcglobal.org/content/view/25/1
Science is a way of trying not to fool yourself. - Richard P. Feynman
Experience is the hardest teacher. She gives the test before the lesson.
If the patient has had success with a similar RX previous, I would consider a single vision slab off. This would accomplish two things. first it would help to thin the left eye a bit more, and second it would help with the anisometropia. Maybe consider doing with an iseikonic design. Trivex would not do anything to thin the left eye(better optics though). How about Cr-39 in the right and 1.70 in the left.
No binocularity, no slab-off. Besides, SV wearers will typically posture to minimize VI.
I just completed an iseikonic for a OD -2.00 OS +.50 needing to increase image size in the right by 3%...OD is about 10mm thick on a +8.75 base. I'll try to remember to snap a photo before dispense. The difference here is 10% or so, making it impractical without CLs. Trivex in the right is for Safety.
Science is a way of trying not to fool yourself. - Richard P. Feynman
Experience is the hardest teacher. She gives the test before the lesson.
he is coming out of a script of :
-2.00 sph
-5.75 -1.25 x 146
1.67 OU aspheric which creates about a 5% magnification difference.
the new script is creating over a 10% magnification difference between the lenses as Robert said. Since he has accommodated to the 5% difference I am wanting to get him back as close to that as possible. I think that may be a pot dream thinking I can improve it that much. The best I'm calculating to is about 8% without contacts.
Ouch! I foresee adaptation problems.... Good luck.
Please show pics.... been awhile since we have made lens like these. Thanks in advance.
And this pt isn't amblyopic? A jump in RX like this is not going to work IMO. I wonder if a clear lensectomy conversation has occurred with this patient yet. What a tough RX, I feel bad for this person.
I wouldn't waste any money or energy on POW compensated or on a higher abbe material. Keratoconus is going to have a reduced visual acuity in the best case scenario it may be small but this is a large discrepancy in script and like previous posters mention you should hope he is suppressing that left eye.
Any sort of Rx comp is going to assume trying to get the optics back to "best form", given this scenario we know that the eye is shaped abnormally so the design assumptions are most definitely not going to be accurate to your patients eye.
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Amazingly I didn't see you mentioned he was keratoconic. Having worked with a lot of keratonconic PT's in the past I can safely say that glasses are not a viable option if the pt wants good VA. The cornea is not only super steep along an axis, its possible its steep along multiple axes. A very irregular cornea indeed! Glasses are not and never will be design for this correction, the optics just wont work right. Plus the RX changes quickly and dramatically sometimes, as is the case with your patient. The only solutions for these patients are GBL RGP's which is the traditional solution and usually work very well. Also, corneal transplants can work but are risky and are reserved for patients that have advanced keratoconus with very thin corneas. So thin that the corneas are at risk of rupture. Lastly, and most excitingly, is collagen crosslinking therapy. Its new in the USA, Europe and Canada have been doing it for years, and it involves special drops to be instilled into the cornea and crosslinked/polymerized via a high energy light source. I have an acquaintance that recently had it done. He said so far its been good. Not a miracle sure but the condition has not progressed further. He did mention that his eye was somewhat painful for a couple days after the treatment.
Not enough data to rule it out. The client is essentially monocular without CLs, and even if unilateral keratoconus is rare, the time and expense is really minimal. I'd keep it on the table at a minimum.
Science is a way of trying not to fool yourself. - Richard P. Feynman
Experience is the hardest teacher. She gives the test before the lesson.
+1
+1
I'd never write an Rx like that.
While this patient may not be a candidate for a surgical procedure, and while he may/may not be able to wear a contact lens, there's no benefit in wearing glasses like this.
Hold the pen with both hands.
I don't believe it was due to keratoconus, but I do have a few clients succesfully wearing RXs similar to this, with all attempts to cut the power on the stronger eye receiving complaints about poor temporal vision in that eye, most notably, when driving and stopped at an intersection. Some form of alternating suppression I suppose.While this patient may not be a candidate for a surgical procedure, and while he may/may not be able to wear a contact lens, there's no benefit in wearing glasses like this.
Science is a way of trying not to fool yourself. - Richard P. Feynman
Experience is the hardest teacher. She gives the test before the lesson.
He is a candidate for the surgical procedure, but not sure when that will be completed. As for right now, the job was ordered and packed with a 4 leaf clover for luck. I'll let you guys know how it goes. Now it's coffee time.
I've had good results with the Shaw Lens for patients with three to four diopters difference between their eyes. You might want to contact them for advice if they think their lens could benefit your patient. http://shawlens.com/
The Shaw Lens sounds interesting, researching it now.
"Eyeglasses are incredibly complicated medical devices"
http://www.optiboard.com/forums/show...free-form-PALs
But your client requires other solutions as discussed above.
Last edited by Robert Martellaro; 03-20-2014 at 08:44 AM.
Science is a way of trying not to fool yourself. - Richard P. Feynman
Experience is the hardest teacher. She gives the test before the lesson.
I agree, I was simply saying the shaw lens looks promising as a product. This particular client of mine has been ordered and expectations have been established with him. The highest recommendation to the client was the surgical procedure, but with the help of the above recommendations I did my best to minimize the magnification issues.
Sorry, I wasn't sure of the context.
I very much doubt that the time, effort, expense, and cosmetic consequences required to reduce OS minification will reap any visual benefits. The eyeglasses will be wearable only if suppression occurs. The prescriber or optician should screen for this before fabrication- if the client drops to their knees when you trial frame (or a quick and easy -5.00 over the spectacles), and there's still diplopia after five minutes (if they can tolerate it for that long!), don't try it (unless the prescriber twists your arm).This particular client of mine has been ordered and expectations have been established with him. The highest recommendation to the client was the surgical procedure, but with the help of the above recommendations I did my best to minimize the magnification issues.
However, if they have a short period of diplopia (or none at all) that resolves, your chances are probably non-zero, but you'll still need to determine as best as you can if the client will really be in a better place with the extra -5.00 OS.
Science is a way of trying not to fool yourself. - Richard P. Feynman
Experience is the hardest teacher. She gives the test before the lesson.
As others have said... you can try all the fancy products you want, all the high index, thinning, BC selection. If the patient does not suppress, they will not be able to wear the spectacles. They won't appreciate any "improved" VA in that eye. Suppressed vision is only 20/200 vision anyway, so the patient might as well have a balance lens and forget all the heroics.
The prescriber here, is likely the uninitiated one and should know better... but he probably rarely eats glass.
Client was about -.50 OU, Rx asked for 3% larger OD, fitted about two years ago, OD was about +8 BC 6mm CT OS +1.00 BC 1.5mm CT. No pictures, but I can still snap a few if you want- they were in a metal frame.
Now there's a nuclear cataract with Rx OD about -2.00 OS +.50, 3% larger OD, requiring a thicker and steeper BC of about OD +10 base 9mm CT, OS plano BC 2mm CT. You can see two small areas where blank thickness was an issue.
Another bump in minus will probably require a CL or CAT surgery.
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Last edited by Robert Martellaro; 03-21-2014 at 05:52 PM.
Science is a way of trying not to fool yourself. - Richard P. Feynman
Experience is the hardest teacher. She gives the test before the lesson.
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