10 year follow up of LASIK surgery for low to high levels of myopia

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10 year follow up of LASIK surgery for low to
high levels of myopia


Qasim Qasem FRCS, Caitriona Kirwan MRCOpth,
Michael OKeefe FRCS.
Institutional Affiliations Mater Private
Hospital1, Eccles Street, Dublin University
College Dublin2, Ireland
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• Introduction
• LASIK, lamellar flap creation followed by laser
  ablation, is largely responsible for the
  popularising of corneal refractive surgery.
• Follow up studies are very important for
  improvement of treatment algorithms, better
  definition of treatment boundaries, management
  and outcome of early postoperative complications,
  monitoring visual acuity results and stability at
  short and long term.

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• Objective
• To evaluate the long term safety and stability
  of laser in situ keratomileusis (LASIK) for the
  treatment of low to high levels of myopia

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• Methods
• Out of Ninety patients invited for review after
  ten years from their refractive laser surgery,
  forty three patients were assessed ( 48 .) .
• All procedures performed by one surgeon (MOK) by
  Technolas 117 laser platform (Bausch Lomb)
• date of surgery, age at the time of surgery,
  refractive error treated, optical zone used, flap
  thickness, ablation depth, early postoperative
  complications, visual and refractive outcome
  three months postoperatively and re-treatments
  recorded.
• At ten year follow up of patients ( 74 Eyes) had
  a full ophthalmic assessment, unaided and best
  corrected visual acuity were recorded, current
  refractive error, Corneal Topography by (Orbscan,
  Bausch Lomb), Aberrometry by (Zywave, Bausch
  Lomb), Corneal hysteresis by (Reichert Ocular
  Response Analyzer), Contrast sensitivity (Pellie
  Robson), Slit lamp examination dilated
  funduscopy.
• All patients were also questioned regarding any
  night vision complaints and satisfaction in
  general.

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• Results
• The average age at the time of surgery was 32.5
  with a range between 20 to 54 years of age.
• Mean refractive spherical equivalent treated was
  -5.67 dioptre, with a range of -1.75 dioptre to
  -12.5 dioptre, target of treatment was
  emmetropia for all patients.
• Preoperative central corneal thickness average
  was 557.5 46.96 (microns), with a range between
  442 to 670 microns.
• Optical zone of treatment average was 5.8 0.4
  mm with a range between 5 to 7 mm.
• Depth of ablation range was 50 to 167 micron,
  with an average of 114.9 26.4 microns, and
  average flap thickness was 160.4 micron.
• There was one intra-operative complication of a
  free flap which was managed with no loss of best
  corrected visual acuity.
• Three eyes out of the seventy four had re-
  treatment at early period within the first year
  and another two were re-treated within the first
  five years.
• At ten year follow up further 7 eyes required
  enhancement

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• 
  Three Months Ten Years
• 6/6 58.1
  49.2
• 6/7.5- 6/9
  22.97 28.9
• 6/12
  8.10 8.6
• 6/15 6/24 5.40
  8.6
• 6/36 6/60 5.40
  4.3
• Three months post treatment Vs 10 Years
  unaided visual acuity

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• Aberration profile
• All patients had an aberration scan at their ten
  year visit.
• Out of the 43 patients, only eight patients (18.6
  ) described some degree of difficulties with
  night vision and continued to experience symptoms
  of glare which was confirmed with aberrometry.
  Majority of patients were asymptomatic even with
  a level of high order aberrations above normal
  level.
• The average high order aberration at 6 mm is
  0.84 0.3 microns, the average 4th order
  spherical aberration is -0.48 0.2 microns.
• The total level of aberration is higher than
  0.80 microns. (Table 3),
• 19 eyes (27.5) had HOA at 6mm higher than one,
  42 eyes (60.8) between 0.5 and 1.00 micron and
  the remaining were below 0.50 microns. (Figure 1)
• Figure 1- Zywave Aberrometry

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• Predictability
• The percentage of patients within plus or minus
  0.5D and plus minus 1.00D of intended correction.
• Within 0.5
  D At 3/12 At 10 Yrs Within 1.0 D
  At 3/12 At 10 yrs
• All levels
  45.9 28.37
  79.73 58.1
• Low Myopia
  57.1 42.80
  100 85.7
• Moderate Mope 58.9
  35.9
  94.8 69.23
• High Mope
  25.0 14.28
  53.7 35.71

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• Retreated Patients
• MRSE Age at Rx
  Regression Sex
• -5.625 D 21
  -1.5 D F
• -7.75 D 45
  -2.0 D F
• -7.375 D 41
  -3.25 D M
• -6.00 D 34
  -1.75 D F
• -5.00 D 29
  -0.75 D M
• -6.5o D 34
  -1.75 D F
• -8.75 D 23
  -3.35 D F
• - 5.0 D 30
  -1.25 D F

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• Conclusion
• at ten year follow up, Lasik is a safe procedure
• however, there was a 15 regression.
• this was mostly in high myopic patients and it
  seems to be associated with the younger patients.
• Recommendation
• Patients with high myopia should be informed of
  the potential to become myopic again and require
  glasses.
• Surgeons treating those patients should be aware
  of this and perhaps build in the option of
  further surgical re-treatment as part of their
  initial surgical approach.