Spherical Aberration vs Depth of Field

Purpose
To compare distance-corrected, near, and intermediate visual acuities as a measurement of depth of focus and spherical aberration of eyes implanted with aspheric and spherical intraocular lenses (IOLs).

Results
Photopic pupil sizes in each group were similar at 30 days after surgery. At 90 days after surgery, mean logarithm of the minimum angle of resolution distance-corrected near visual acuity (±standard deviation [SD]) was 0.50±0.20 in the AcrySof IQ group, 0.38±0.17 in the AcrySof SN60AT group, and 0.45±0.16 in Sensar AR40 group. Mean spherical aberration values (±SD) were 0.03±0.05 μm in the AcrySof IQ group, 0.24±0.04 μm in the AcrySof SN60AT group, and 0.14±0.07 μm in the Sensar AR40 group. The AcrySof IQ group showed a statistically significant lower induction of spherical aberration and worse distance-corrected near visual acuity. The AcrySof SN60AT group showed statistically significant higher mean spherical aberration values and better distance-corrected near and intermediate visual acuity.

Conclusions
The reduction of total spherical aberration after aspheric IOL implantation may degrade distance-corrected near and intermediate visual acuity.

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Another study concluded:  
"Although best corrected optical quality is significantly better with aspheric IOLs, tolerance to defocus tended to be lower."

Oh man.... as if I wasn't confused enough already!  :-)

[LynneAV]

Yes, can that be explained in plainer English? I just had an aspheric IOL implanted, resulting in correction of near-sightedness in that eye.

[sally987]

And I had the SN6AT4 and 5 implanted.  Thanks, NeLso

[JodieJ]

In plain English these findings suggest that (on average) aspheric IOLs provide slightly better distance acuity (and contrast sensitivity), and conventional spherical IOLs provide slightly better intermediate and near acuity.  However, the findings do not state whether these differences in acuity are meaningful (i.e., can people actually see a difference in their vision).  The answer seems to be that most people cannot perceive a difference.

Another relevant issue:  I believe that these (and similar) results were obtained with both eyes set at plano.  Many people prefer some version of (modified) monovision.  It's anyone's guess how this might skew the results.

It's my (non-professional) opinion that your choice of surgeon is far more important than your choice of monofocal IOL.



  

[LynneAV]

Thank you Jodie, I appreciate the clarification.

I am two weeks post-op, AcrSof IQ. Dominant and near-sighted cataract eye was corrected to incredible (my layman opinion) clear distance vision. Other eye is only very slightly near-sighted. I am functioning without glasses for the first time since I was 18 months old, I'm 60 now. This is some kind of dream I keep thinking I will wake up from any minute. I only need magnifcation for tiny type and threading needles, but that happened when the cataract occured, so I was without clear closeup vision even before the lens implant. This is pretty amazing to me and very much better than my expectations.