Pilot Study: The Effect of Radial Sutures on High Astigmatism After Penetrating Keratoplasty

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Pilot Study The Effect of Radial Sutures on
High Astigmatism After Penetrating Keratoplasty

• Maayan E. Keshet, M.D.
• Maggie B. Hymowitz, M.D.
• John J. Kim, M.D.
• Albert Einstein College of Medicine
• Montefiore Medical Center

Neither author has any financial interest to
disclose
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Introduction

• Patients with high degrees of astigmatism present
  special challenges for the refractive surgeon and
  clinician1, 2, 3.
• Although a variety of surgical options are
  available for correction of mild astigmatism
  (less than -2.50 diopters), there is no effective
  surgical way to correct higher degrees of
  astigmatism (greater than -5.00 diopters).
• Particularly affected are post-corneal
  transplant patients who often suffer from high
  cylindrical errors4.

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Introduction

• As opposed to the incisional (AK and LRI), that
  function by flattening the corneas steep
  meridian, we attempted a suturing technique which
  would steepen the corneas flat meridian.
• Unlike AK, LRIs, PRK, LASIK, and toric IOLs, the
  procedure was reversible the prolene sutures
  could be easily removed at the slit lamp.
• It also avoided complications such corneal
  ectasia, significant scarring, or haze.
• Furthermore, the corneal sutures were able to
  induce high levels of astigmatism that effect
  powerful cylindrical change in the desired axis.

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Methods

• Standard IRB approval was obtained (07-10-357E)
• Post-PKP patients routinely examined in the
  ophthalmology clinic were screened for astigmatic
  refractive errors -5.00 diopters.
• Those choosing to participate in the study were
  consented and enrolled.
• All participants had their best-corrected and
  uncorrected refractive error determined, along
  with auto-refraction and corneal topography at
  the following time intervals before the
  procedure (pre-suture), post-suture, at one day,
  one week, one month and three month
  post-procedure.

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Methods

• The axis of the flat meridian of the cornea was
  determined with an auto-refractor and the NIDK
  MagellanMapper corneal topographer.
• Once prepped and draped in the usual sterile
  fashion, topical 2 lidocaine jelly and a lid
  speculum were placed in the study eye.
• Two radial 10-0 Prolene sutures were placed along
  the flat corneal meridian at 180º from one
  another.
• One drop of Vigamox was applied to the eye
  before and after the procedure.
• Subjects were instructed to use one drop of
  Vigamox, four times a day in the study eye for
  one week.

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Results

• Subject 1

Pre-suture
Post-suture
presuture
Post-op day 1
Post-op week 1
Post-op month 1
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Results

• Subject 1

Time Uncorrected VA Autorefraction
Pre-suture 20/400 PH 20/1002 -0.25 -8.50 X 10
Post-suture 20/200 PH NI -.50 -4.00 x 23
POD1 20/200 -1.00 -3.00 x 24
POW1 20/200 -1.75 -4.00 x 12
POM1 20/100 -1.25 - 5.00 x 8
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Results

• Subject 2

Pre-suture
Post-suture
Post-op day 1
Post-op week 1
Post-op month 1
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Results

• Subject 2

Time Uncorrected VA Autorefraction
Pre-suture 20/70-1 PH 20/60-2 -0.50 - 6.50 145
Post-suture 20/200 PH 20/30 -3.50 -1.75 x 170
POD1 20/30-2 PH NI -1.50 -4.00 x 140
POW1 20/70 PH 20/30 -0.75 -5.75 x 155
POM1 20/200 PH 20/30 Pl -5.75 x 160
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Results

• Subject 3

Pre-suture
Post-suture
Post-op day 1
Post-op month 1
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Results

• Subject 3

Time Uncorrected VA Autorefraction
Pre-suture 20/701 PH NI -0.75 -6.75 170
Post-suture 20/301 -5.75 -2.50 x 145
POD1 20/40-3 -5.25 - 1.50 x 145
POW1 20/100 PH 20/70 -2.25 -5.75 x 165
POM1 - -
Sutures removed due to loosening, severe
photophobia and irritation
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Conclusions

• Although the Prolene radial sutures improved
  astigmatism considerably in the first day and
  week post-operatively in our three subjects,
  their effects diminished over time.
• Loosening of sutures or dynamics of corneal
  elasticity may have limited the ability of two
  simple prolene sutures to correct high diopter
  post-keratectomy astigmatism.