Visual acuity with cataract lenses

[VisualAcuity]

I am trying to select a cataract lens and am currently trying to choose between a monofocal lens and Restor. My question is: Shouldn't it be possible to chart my current visual acuity as a function of distance from either my current eye glass prescription which is for both near and far vision (crude) or from a series of tests (more accurately) and compare that with charts of visual acuity as a function of distance for each of the lenses that I am considering.

I realize that a new set of tests would have to be run on my non-cataract eye. But, since my vision was similar in both eyes, I would be ok with that.

I was quite happy with my vision before the cataract, even though I had to wear glasses for driving, and would be very happy simply to restore my vision to what it was without all the potential side effects of the new high tech lenses. I think that charts of visual acuity as a function of distance for my eyes and all the lenses I am considering would do more than any other single factor to help me select the right lens.

[VisualAcuity]

Then what is Figure 4 in "Deciphering Diffraction" by James Davison in Cataract & Refractive Surgery Today:

http://www.crstoday.com/PDF%20Articles/0605/CRST0605_F2_Davison.html

and why was I able to obtain Snellen readings for near, intermediate, and distance vision at my ophthalmologist's office that I can superimpose on that Figure, thus obtaining a fairly accurate curve for my own eyes?

[John C Hagan III, MD, FACS, FAAO]

1. NO
2. NO

JCH MD

[VisualAcuity]

I appreciate the time that people are spending on the Eye Care forums.

But I have now asked my questions 4 times and have yet to get an answer to them.

My questions are:
1. Is it possible to get a chart of visual acuity as a function of distance for my eyes and for the lens that are available for my eyes?
2. Is it possible to get a feel for the amount of blur that you will have at various distances from the charts in the first question or from your eye glass prescription? Not a precise understanding, just a feel.

I know that I can simulate the monofocal feel with contacts. I know that I can get a different surgeon. I have read the studies on your website. But I am scheduled to have surgery in 2 weeks and, if I cancel, I probably will not be able to reschedule surgery until the fall.

So I would like it if I could get an answer to my questions. If the answer is "No the two things you are asking about are not possible and here is the reason why." that is fine.

[John C Hagan III, MD, FACS, FAAO]

The best way to get a monofocal feel is with contact lens to simulate.

If you feel you are being forced to get a premium IOL consider a different surgeon. Those type of practices are not professional.

Go to the Review of Ophthalmology website, april 2009 issue and read the study by Dr. Kutryb and me based on these two websites. Premium IOLs cause 60 times more complaints than monofocal IOLs.

JCH MD

[VisualAcuity]

Thank you for your comment.

I know that I will need an IOL calculation before having surgery. What I am trying to do now is get a ballpark feel for what a nearsighted monofocal lens would be like. In a paper called Deciphering Diffraction (see

http://www.crstoday.com/PDF%20Articles/0605/CRST0605_F2_Davison.html

Figure 4 shows Snellen visual acuity as a function of Refraction for the Restor lens and a far sighted monofocal lens. The figure notes near, intermediate, and far distances. The Restor lens shows 20/20 vision at distance (0.0D) and near (-3.0D) distances and 20/40 at intermediate distance (-1.5D). I would guess that a near sighted monofocal lens curve would look like the near portion of the Restor lens extrapolated linearly for distance vision (or the curve for the monofocal far sighted lens flipped about its vertical axis at the intermediate vision distance.

If I look at my prescription and/or test my vision with a Snell chart, I believe that the results fairly closely match the curve for a nearsighted monofocal lens that I cited above. I have been told by one ophthalmologist that I could restore my precataract vision with a nearsighted monofocal lens. Nevertheless, ophthalmologists are pushing me to get a "premium" lens.

It seems to me that I should be able to get a ball park feel for my visual experience with a monofocal lens before seeing my surgeon.

My right eye prescription (prior to the cataract) was -1.25 -0.75 x 10 at distance and Plano -0.75 x 10 for near vision.

[John C Hagan III, MD, FACS, FAAO]

-

[peakhope]

Be sure you fully understand the risks and drawbacks of each lens. For Restor, there is a significant risk of disturbing night-time glare. With monofocal lenses, you will probably have little if any "accommodation", meaning you would only see clearly at whatever distance the lenses are set for, and would need glasses to see objects that are nearer or farther than that.

Personally, I chose Crystalens HD's over those two options. But there is no single best lens for everyone. It depends on your own lifestyle and interests. There is no perfect IOL yet, so none is likely to give you the quality of vision at all distances that you had before.

And of course there are risks with any IOL. Choose the best possible doctor to give yourself the best chance of success.

[John C Hagan III, MD, FACS, FAAO]

The short answer is no you need special tests to help determine the correct IOL power.

JCH MD