Use of Bandage Contact Lenses BCL Increases the Incidence and Severity of Epithelial Ingrowth Follow

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Use of Bandage Contact Lenses (BCL) Increases the
Incidence and Severity of Epithelial Ingrowth
Following LASIK Enhancement

• Sophie Beaulieu
• Mark Cohen, MD, FRCSC
• Mounir Bashour, MD, FRCSC
• Pierre Demers, MD, FRCSC
• Avi Wallerstein, MD, FRCSC

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Introduction

• Epithelial ingrowth (EI) is a common complication
  following LASIK retreatment
• Pérez-Santonja et al.2 report an 8.5 frequency
  of occurrence following primary LASIK surgery.
• However, 6 months following LASIK enhancement,
  the occurrence of EI climbed to 32.

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Background

• Some surgeons routinely use bandage contact
  lenses (BCLs) following LASIK enhancements with
  the belief that the use of a BCL may reduce the
  incidence of epithelial ingrowth our central
  hypothesis for this study

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What Causes EI?

• 1) Surgical instrumentation used during the
  procedure introducing epithelium directly into
  the interface
• 2) Primary ingrowth of epithelial cells under
  the edges of the flap postoperatively due to poor
  adhesion secondary to
• - surgical trauma DLK edema

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Central Hypothesis

• Insufficient adherence of the flap edges to the
  stroma may favor EI.
• Similarly, small irregularities in epithelium and
  edema at the edges of a relifted flap can lead to
  the same effect.
• It is hypothesized by some surgeons that the use
  of a BCL may provide mechanical pressure
  increasing flap adherence and protecting from
  sweeping of cellular debris under the flap during
  blinking.
• To our knowledge this is the first time this
  hypothesis has been formally studied.

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Purpose

• To assess how BCLs affect both the incidence
  and severity of epithelial ingrowth post LASIK
  enhancement.

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Materials and Methods

• Subjects
• 96 eyes of 48 subjects undergoing same-day
  bilateral enhancement were included in the study.
• Selection Criteria
• Must have previously undergone bilateral LASIK.
• Regression of a spherical equivalent of at least
  -1D.
• Patient motivated to undergo bilateral
  enhancement to correct residual ametropia.
• Uneventful enhancement requiring no additional
  surgical intervention.

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Materials and Methods

• The study design was comparative between eyes
  one eye used as the treatment group and the
  contralateral eye as a control. Factors such as
  age and flap thickness were therefore controlled.
• Immediately after flap repositioning, the treated
  eye received an etafilcon A lens (Acuvue2 BC 8.7
  dia. 14mm) while the control eye received no
  lens. The eye to receive the lens was determined
  at random before the retreatments.

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Measurement of EI
Height 1.8 mm
Sample measurement of a medium-sized epithelial
infiltrate. Further invasion of cells towards the
visual axis may be visually threatening.
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Results

• At all post-op visits the eye with the BCL had a
  statistically significant
• increased incidence and severity of epithelial
  ingrowth.
• t-tests for depth of ingrowth (measure for
  severity) at all f/u times is shown below

Only 1 eye out of all 96 had epithelial ingrowth
severe enough to warrant its surgical removal
(the eye had a BCL).
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Results

• This mosaic plot shows the fronds of ingrowth
  (measure for incidence) depending on if a BCL was
  used or not, BCLs not only increase severity but
  also incidence as measured by fronds of ingrowth

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Discussion

• Corneal edema caused by contact lens wear may
  interfere with flap adherence leading to the
  infiltration of epithelia.
• Acuvue2 lenses (Dk/L 33.3) induce an approximate
  corneal oedema of 10 during periods of
  extented-wear on virgin corneas. A Dk/L value of
  at least 87 may reduce corneal oedema to about
  4.
• Our initial hypothesis suggested that palpebral
  movements were part of the mechanism underlying
  EI.
• The inability of BCLs to protect the cornea from
  EI discredit the hypothesis that eyelids are part
  of the pathway leading to this complication.

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Conclusion

• Bandage Contact Lenses appear to predispose,
  rather than prevent, epithelial ingrowth after
  LASIK enhancement.
• Eyelid involvement in the pathway leading to EI
  is likely minimal or inexistent.
• Further investigation may warrant the use of BCLs
  with higher transmissibility values to decrease
  the incidence of corneal oedema thought to
  predispose the cornea to EI.