Wavefront-Guided LASIK Using the VISX CustomVue

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Wavefront-Guided LASIK Using the VISX CustomVue
Star S4 Laser System With and Without Iris
Registration A Retrospective Comparative Study

• Sonal B. Dave, MD
• Ladan Espandar, MD
• Majid Moshirfar, MD
• John A. Moran Eye Center
• Salt Lake City, Utah

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Purpose

• To compare visual outcomes after laser in situ
• keratomileusis (LASIK) using the VISX Star S4
• CustomVue, with and without Iris
• Registration (IR) technology.

Is there a difference between Iris Registration
and non-Iris Registration LASIK?
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Methods

• Retrospective study
• 239 myopic eyes of 142 patients with or without
  astigmatism underwent LASIK
• Primary LASIK treatment with the VISX Star S4
  CustomVue laser (VISX Incorporated, Santa Clara,
  CA) with or without Iris RegistrationTM
  technology
• 121 eyes with IR
• 118 without IR
• Primary outcome measures uncorrected visual
  acuity (UCVA), best spectacle-corrected visual
  acuity (BSCVA), and manifest refraction
• Secondary outcome measures higher-order
  aberrations (HOA) and vector analysis of residual
  astigmatism

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UCVA 6 months post LASIK
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6 months post LASIK
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Postoperative month 3 (0.5 D lines)
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Change in BSCVA (Snellen lines) 6 months
postoperatively
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Results

• At 6 months, the mean values for logMAR UCVA
• 0.00 0.09 in the IR group
• -0.01 0.11 in the non-IR group (p0.587)
• UCVA of 20/20 or better
• 79 of eyes in the IR group
• 73 in the non-IR group (p0.518)
• Within 0.5 D of emmetropia
• 92 of the eyes in the IR group
• 90 in the non-IR group (p0.999)
• Mean postoperative absolute changes in total root
  mean square (RMS) higher order aberrations HOA
  (µm)
• IR group 0.22
• non-IR group 0.19 (p0.6)
• At 3 months, the mean magnitude of error of
  surgically induced astigmatism
• -0.09 in the IR group
• -0.04 in the non-IR group (p0.24)

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Why did IR not have better outcomes?

• Eyes were marked at the limbus and patients were
  adjusted accordingly
• IR was performed prior to lifting of flaps
  resulting in possible patient movement after iris
  verification
• Stromal remodeling and epithelial hyperplasia may
  mask benefits of IR
• Other thoughts???

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Conclusions

• Wavefront-guided LASIK with the VISX Star S4
  CustomVue laser system, independent of Iris
  Registration status, is effective, safe, and
  predictable.
• This study did not find any statistical
  significance supporting the better achievement of
  visual acuity, astigmatism correction, or the
  lesser induction of HOA using Iris Registration
  in comparison to a non-Iris Registration system.

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References

• Supported in part by an unrestricted grant from
  Research To Prevent Blindness, Inc., New York,
  NY, to the Department of Ophthalmology and Visual
  Sciences, University of Utah
• http//joneseyecenters.com/images/content/joneseye
  centers/Iris_Registration_Image.jpg
• http//www.cullomeyecenter.com/images/content/visx
  S3_fullview_sm.jpg
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