IOL test drive

I'm going through the history of posts related to mono-vision (thank you so much board members!) and came across several postings where the target focus was off, some significantly.

Just a silly question, would it not be possible to do a "which is better, Aieee... or Beeeee?"  (ie. similar to getting a fitting for eyeglasses).  Would it be possible to rest a test IOL on the cornea so that patient can get an idea of what to expect?

But then again, I guess it would be pretty hard to do if the patient is flying high as a kite!

[JodieJ]

Yes, it's absolutely possible to "test drive" monovision using disposable contact lenses.  (Since IOLs must be implanted, they wouldn't work for this purpose.)  Actually, it would be very wise for anyone considering monovision to try out the correction with contacts first, if possible.  The only thing to keep in mind is that making IOL power predictions is not an exact science.  On the "expert" forum, I think that Dr. Kutryb said that he likes to do the distance eye first for a patient wanting (distance bias) monovision.  His plan for the second eye would be contingent on the results of the first eye.  I suppose that the correction could always be tweaked with LASIK/PRK if things don't go exactly as expected.      

[farmerjon101]

This is a great question for me as well...can you do a test drive with lens if you have had lasik which I had done 10 years ago.
Thanks

[LynneAV]

Wouldn't you need to have the foresight to do the contact lens test drive before you developed a cataract and lost sight?

[Ray T Oyakawa, MD]

This "test drive" can help if the cataract is not too bad.  I do not recommend monovision for patients who did not use monovision prior to cataract surgery.

Dr. O.

[JodieJ]

I believe that there are currently better formulas for making IOL power predictions if you've had LASIK.  Check out Dr. Hagan's comments about this in the archives.

[NeLso]

Hi everyone,

Sorry for the confusion....  The "test drive" that I was referring to was to get the exact IOL power during surgery.  

In some prior posts, the patients indicated that the IOL power incorrect and instead of plano, they got intermediate vision, or vice-versa.  I was just wondering why it isn't possible to place different IOL powers on top of the cornea (or very near it) and then have the patient read an eye chart (on the ceiling) during surgery.  Insert the IOL that sets the patient most closely to plano.  (ie. no guess work?)

[JodieJ]

The positioning of the IOL inside the eye has a big effect on its refractive power.  Sometimes the position of the IOL moves after its been implanted, and this will change the person's refractive error (for better or worse).  So putting an IOL on top of the cornea would not produce useful information.  There is a new type of IOL being test marketed in Europe (and maybe elsewhere) whose power can be adjusted after it has been implanted, and I've read that the outcomes have been promising.

If you have an experienced surgeon who uses an IOL Master, your results will probably be pretty close to your target.  The formulas for making power predictions are supposed to work a little better for people who aren't very nearsighted or very farsighted, but we don't have much control over this.