Spherical Aberration & IOLs

[Glad4Help]

I am trying to decide between Crystalens and aspheric monofocal lens and have the following questions:

1. Is it true that Crystalens does NOT correct for spherical aberrations?  If so, could I expect crisper vision with an aspherical monofocal IOL?  

2. I have read that studies show that the Akreos AO lens provides a greater depth of field than other aspherical lenses, but the articles don’t say if this gives more near vision or more far vision.  Does anyone know how this works?  

3. Is spherical aberration more pronounced in farsighted or nearsighted eyes?  (I am severely farsighted and wonder if this issue is more or less critical for me when deciding between a Crystalens or an aspheric monofocal.)

[Michael J Kutryb, MD]

Yes, aspheric IOL's in patients tend to statiscally perform better regarding low contrast sitatuions like driving at dusk.  The most studied lens is the tecnis and touts some fairly impressive findings so I personally would want an aspheric lens if I needed cataract surgery.  Now to be truly honest, it is nice to know exactly what the spherical abberation is in order to custom choose the IOL to maximize the correction.  Again, I think you are getting way too deep into this.  I would find the best cataract surgeon in your area and that is the most important thing.  The crystalens by its flexible nature can sometimes result in a little unexpected myopia but fortunately this can be corrected with lasik or prk or other refractive procedures.

MJK MD

[Michael J Kutryb, MD]

To be honest, if you are highly farsighted, you will probably love a standard IOL or an aspheric IOL as long as your refractive error is well corrected.  In the real world, I doubt you would notice the difference between a standard or aspheric IOL.  We do know statistically, that overall, the contrast sensitivity and spherical abberation will probably be better over large numbers of patients, but whether or not that will translate into you personally having better vision, I really can't say.  If your surgeon has a wavefront machine or a Zeiss Atlat topography, then the current corneal spherical abberation can be measured and IOL can actually be picked to try to maximally correct your spherical abberation error.  I would make your decision basically on either an aspheric monofocal (any brand is about at good, bausch and lomb, alcon, or amo) or the crystalens which will cost more and possibly provide a little more near vision but also a slightly higher chance of unwanted refractive error and need for postoperative tweaking with lasik or prk.  By the way, the acryos is a good lens but not really better, in my opinion, than the the tecnis, or acrysof IQ or sofport AO, the other aspherics.

Michael Kutryb, MD

[Glad4Help]

Dr. Kutryb,

Your comments were very helpful.  I have a couple follow-up questions for clarification...

When you said, "that overall, the contrast sensitivity and spherical abberation will probably be better over large numbers of patients,"  did you mean that this is the case for the aspheric IOLs?

Also, regarding the statement, "[Crystalens could produce] slightly higher chance of unwanted refractive error,"  does that mean that the replacement lens calculations could be off  becasue it's more difficult to calculation for the Crystalens?

Thanks very much for your help!

[Glad4Help]

One more aberration question:

If I got a plain old standard IOL, could spherical aberration be corrected with glasses?