Managing%20the%20Refractive%20

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Managing the Refractive Surprise After Toric
IOL Placement

• Brad H Feldman, MD
• Derek DelMonte, MD
• Alan N Carlson, MD

Duke Eye Center Durham, NC
Authors have no financial interests
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Case Presentation

• 53 year-old man referred to the Duke Eye Center
  for 2nd opinion regarding residual astigmatism
  after undergoing cataract extraction with Toric
  IOL left eye
• Patient originally chose Toric IOL on surgeon
  recommendation to achieve astigmatic neutrality
  and decrease spectacle dependence
• Patient completely unsatisfied with outcome
  immediately after surgery
• Surgeon indicated there was nothing more he could
  offer the patient

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Prior Ocular History

• Note patient underwent myopic LASIK OU in 1999
  with monovision OS
• Pre-LASIK OS MRx -6.75 1.25 x 080
• Post-LASIK OS MRx -1.50 sphere
• Cataract noted in August 2007 with BCVA of 20/50
  OS
• OS MRx -3.00 1.25 x 170

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Prior History Continued

• Pre-Cataract Surgery Evaluation OS
• April 2008 (Still at Outside Facility)
• MRx -2.75 -1.00 x 170 BCVA 20/60
• Orbscan Keratometry 42.90/43.70 x 098
  0.8D x 098
• IOL Master K Values 42.13/43.21 x 092
  1.1D x 092
• Manual Keratometry 40.20/42.20 x 098
• 2.0D x 098
• US Pachymetry 479 microns

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IOL Calculations (Outside Facility)

• Patient chose Toric Premium Lens
• Lens Power
• IOL Master Derived
• SRK/T Clinical History Method
• Astigmatism Power
• Alcon AcrySof Toric Calculator Used
• Based on Manual Ks
• As per instructions of online calculator
• Note difference in power of K axes between
  Orbscan, IOL Master, and Manual Ks (see prior
  slide)

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IOL Calculations
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Postoperative Course

• UCVA 20/60 plano 2.50 x 100 20/20
• Examination
• Axis flipped despite properly achieving the
  intended axis
• Position asymmetric fixation, superior loop in
  sulcus, inferior loop in bag, optic decentered
  superiorly and tilted
• Assessment
• Pantoscopic tilt with optic decentration making
  astigmatic correction by the IOL overly
  effective, causing over correction and axis flip
• Plan Reposition lens for symmetric bag fixation
• Please view attached video for details

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Post-Repositioning Course

• UCVA 20/60
• MRx 0.75 2.75 x 100 20/20
• Examination
• Reveals correct Toric IOL position, centration,
  axis
• Atlas Topography 42.50/42.62 x 090
• 0.12 x 090
• Pentacam Holladay Equivalent Ks (4.5mm zone)
• 42.00/42.90 x 110
• 0.90 x 110

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Post-Repositioning Course

• Our initial assessment in consultation supported
  an improperly implanted IOL as the culprit for
  the astigmatic axis flip.
• The patients outcome after his second surgery
  indicates the original IOL selection error was
  based on using a post-LASIK manual K reading.
  Additional data revealed this was inconsistent
  with other astigmatism measurements.
• Patient remains frustrated and is now
  contemplating IOL exchange.

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Discussion

• The differential diagnosis for a surprise
  result after surgery includes
• Wrong astigmatic power calculation and IOL
  selection
• Incorrect astigmatic axis alignment
• Incorrect Toric IOL location resulting from
  decentration or optic tilt
• Surgical or postoperative induction of
  astigmatism related to wound healing or IOL optic
  rotation

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Summary

• 53 yo h/o LASIK unsatisfied due to astigmatism
  following cataract surgery with Toric IOL
• Toric IOL was selected on the basis of manual K
  readings as recommended by IOL selection protocol
• Original measurements were inconsistent
• IOL Master ? Orbscan ? Pentacam ? Manual Ks
• Our error was attributing the initial surgical
  outcome entirely to faulty IOL fixation and
  position
• There was optic tilt and decentration secondary
  to asymmetric capsular fixation from the original
  surgery
• Astigmatism remained despite proper repositioning
  
• This suggests the original surgeon used manual
  K readings which were incorrect after previous
  LASIK surgery

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Conclusion

• Measuring corneal astigmatism after refractive
  surgery requires multiple methods and more
  critical analysis for consistency before
  recommending astigmatism-correcting Toric IOLs.
• Critical analysis and caution are warranted when
  considering a Toric IOL in cases having
  discrepancies between different methods of K
  readings