Comparison of topography-guided (TGL) to standard LASIK (SL) for hyperopia. How important is adjustment for angle kappa? ASCRS 08

1
Comparison of topography-guided (TGL) to standard
LASIK (SL) for hyperopia. How important is
adjustment for angle kappa? ASCRS 08

• A. John Kanellopoulos, MD
• Associate Professor NYU, New York
• Director, Laservision.gr, Athens, Greece
• www.brilliantvision.com

2
We have reported our topo-guided experience in
LASIK utilizing the Wavelight-platform
(Kanellopoulos-JRS Sept05)

• The software feeds 8 high quality topographies
  (Oculus) and offers surgeon adjustment for final
  ablation for
• 1-sphere
• 2-Cylinder
• 3-Axis
• 4-Q value (asphericity)
• angle-kappa adjustment is done by default. So the
  ablation is decentered to target the visual axis

3
We have reported our experience with LASIK for
treating hyperopia with the standard Wavelight
platform Kanellopoulos-JRS 2006
Initial topography guided Hyperopic and Hyperopic
Astigmatism LASIK Experience with the WaveLight
ALLEGRETTO WAVE excimer laser in 120 Consecutive
Eyes ARVO 2006-JRS 2006
4
Is Angle kappa significant in hyperopes?

• We published the study Measurement of angle
  kappa with synoptophore and Orbscan II in a
  normal population Hikmet Basmak, MD1 Afsun
  Sahin, MD2 Nilgun Yildirim, MD3 Thanos D.
  Papakostas, MD4,5 and A. John Kanellopoulos,
  MD4,52007 J Refract Surg-
• We showed as previous investigators have that
  there is a significant correlation between
  positive refractive errors and large positive
  angle kappa values. Refractive surgeons must take
  into account angle kappa especially in hyperopic
  patients in order to avoid complications related
  to decent ration of ablation zone.

5
Purpose-why really use topo-guided for hyperopia?

• We evaluated the Safety and efficacy of
  Topo-Guided LASIK (that compensates for angle
  kappa) versus standard hyperopic LASIK
• Compare to previous data from previous published
  standard treatments(including ours)
• Can we safely and effectively compensate for
  angle-kappa by using this platform?

6
An example of a topo-guided hyperopic correction
(1 is after, 2 is pre-op and 1 minus 2 the
difference showing that the ablation is
decentered when referenced to the pupil)
Treatment axis is centered on the visual axis and
not pupil center
7
METHODS

• SETTING Laservision.gr Institute, Athens,
  Greece. 35 patients treated with TGL in one
  eye, SL in the other.
• The Wavelight and Intralase systems were used.
• Refraction, UCVA, BSCVA, angle kappa effective
  ablation diameter (EAD), wavefront analysis (WA)
  and contrast sensitivity (CS) were evaluated with
  18 months follow-up.

8
How is Angle kappa adjusted withtopo-link

• These figures depict the same planned excimer
  profile for the correction of hyperopic
  astigmatism on the left centered on the
  pupillary center and on the right adjusted by
  topography to take into consideration and adjust
  for angle kappa

9
A LASIK flap with a microkeratome needs to be
de-centered as well to accommodate the
de-centered ablation this may beChallenging for
the surgeon. The Intralase offers a better option
to customise the flap cnetration
10
Results

• Mean pre-op sphere for both groups
• 3.08 (SD/- 1.56) D.
• Cylinder 1.80 (SD/- 1.01 D).
• Post-op Mean post-values Topo guided compared tp
  Standard
• UCVA 20/20 to 20/23.
• Regression 0.32 to 0.55.
• Cylinder 0.25 to 0.54.
• Ablation diameter 6.8 to 6.2 mm,
• Wavefront 0.25 to 0.37.
• Contrast sensitivity 40 to 15.

11
A head on comparison of the post-hyperopic LASIK
Pentacam map in the same patient The topo-guided
eye on the left and standard on the right
12
Conclusions

• Topo Guided LASIK and Standard LASIK with the
  Intralase and the Wavelight laser appear to be
  safe and effective for hyperopia.
• Topo-guided appears be superior in regard to
  regression, residual astigmatism, Contrast and
  ablation diameter
• This platform achieves superior visual axis
  centration with a smaller re-treatment rate
  compared to our previously published series.
• It reduces the chance of a surgeon-related
  de-centration error.
• Oculyzer-link maybe faster and more-accurate