Intrastromal Ring Segment Insertion with Femtosecond Laser in Keratoconus

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Intrastromal Ring Segment Insertion with
Femtosecond Laser in Keratoconus

• Marc Doat, B Amari, JL Bourges, A Sartafi, A
  Abenhaïm, G Renard, JM Legeais
• Service dOphtalmologie de l Hôtel-Dieu, Paris,
  FRANCE

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Purpose and Methods

• To evaluate the safety and the efficacy of Intacs
  inserts in keratoconic eyes using the femtosecond
  laser IntraLase FS 60 kHz (IntraLase corp.)
• Prospective study
• 29 eyes of 26 patients
• Inclusions criteria
• Keratoconus (Kc)
• Clear cornea
• Lens intolerance

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Methods

• Surgical method
• All procedures was performed with IntraLase FS
  60 kHz
• Laser parameters
• Channel depth 80 of the central corneal
  thickness
• Energy 2.0 µJ
• Channel size
• - inner diameter 6.6 mm
• outer diameter 7.6 mm
• Incision axis 30 over the temporal extremity
  of the Intacs

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Methods
One or 2 Intacs depending to the keratoconus (Kc)
features and the spherical equivalent (SE)

• Kc not crossing the 180 meridian 1 single
  Intacs
• If SE lt 0 ? 0.45 mm
• If SE 0 ? 0.40 mm

• Kc crossing the 180 meridian 2 Intacs (same
  thickness)
• If SE gt -3 ? 0.45 mm
• If SE -3 ? 0.40 mm

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Methods

• Preoperative and postoperative evaluations
• Uncorrected visual acuity (UCVA)
• Best spectacle corrected visual acuity (BSCVA)
  with sphere, cylinder and SE
• Biomicroscopy
• Orbscan et Pentacam
• Keratometry
• Topography
• Pachymetry
• Postoperative Day 10, Month 1, M3, M6

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Results

• Implantation
• - 11 eyes 2 Intacs
• 18 eyes 1 Intacs
• Procedures IntraLase
• - No complication
• ? Safe
• - All eyes were successfully implanted
• ? Reproducible Procedures

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Results

• Uncorrected visual acuity (M3)
• Mean UCVA pre-op.   1.23 0.24 L (LogMar)
  1/16 (Snellen)
• Mean UCVA post-op. 0.54 0.39 L 3/10 (S)
  
• ? Statistically significant plt 0.001
• Mean UCVA improved for 24 eyes (84)
• Loss of UCVA 0 eye
• No statistically significant differences between
  D10,M1 and M3.

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Results

• Best-spectacle corrected acuity (M3)
• - Mean BSCVA pre-op. 0.57 0.29 L 2.5/10
  (S)
• Mean BSCVA post-op. 0.37 0.32 L 4/10
  (S)
• p 0.001
• Mean BSCVA improved for 20 eyes (69)
• Loss of BSCVA gt 1 line 0 eye
• No statistically significant differences between
  D10,M1 and M3.

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Results

• Refraction
• - Mean sphere  pre-op.   -3.88 3.2 D
• - Mean sphere post-op. -2.17 2.2 D
• p 0.001
• - Mean cylinder pre-op.   -3.97 1.7 D
• - Mean cylinder post-op. -2.92 2.3 D
• ? p 0.05
• - Mean SE pre-op.   -7.23 4.5 D
• - Mean SE post-op. -5.17 3.7 D
• ? p 0.01

• Keratometry (3 mm)
• - Mean Km pre-op.  51.9 5.1 D
• - Mean Km post-op. 49.7 5.0 D
• p 0.01

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Exemples
Kc not crossing the 180 meridian 1 Intacs
Pre-op UCVA 1 logMar
Post-op UCVA 0.3 logMar
Kc crossing the 180 meridian 2 Intacs
Pre-op UCVA 1.3 logMar
Post-op UCVA 0.5 logMar
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Complication

• Explantation
• Two Intacs from 2 eyes removed because of
  partial extrusion after 2 months

Intacs extrusion
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Conclusion

• Implantation using laser IntraLase
• safe
• reproducible
• The IntraLase laser procedure to insert Intacs
  was an efficient procedure to reduce keratoconus
  induced ametropia within 3 months in our patients