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CompletedNCT00889941Updated Apr 29, 2009

Effect of Preoperative Pupil Size on Quality of Vision After Wavefront-Guided LASIK

A Phase 4 interventional study of LASIK in Myopia, sponsored by Stanford University. Completed at 1 site in United States. Per ClinicalTrials.gov, last updated 2009-04-29.

Sponsored by Stanford University · Phase 4, Interventional, and Treatment

Phase
Phase 4
Study type
Interventional
Enrollment
51
Allocation
Non-randomized
Sex
All
01

Study summary

The purpose of this study is to evaluate whether the size of the pupil has an effect on quality of vision in patients undergoing LASIK surgery.

Read the detailed description

Purpose: To prospectively evaluate the effect of preoperative pupil size on quality of vision after wavefront-guided LASIK.

Methods: Fifty-one patients underwent LASIK for low myopia and completed questionnaires regarding specific visual symptoms before and after surgery. Each eye was evaluated postoperatively at 1-week, 1-, 3-, 6- and 12-months. Pupils were stratified according to size: small (\<5.5mm), medium (5.5 to 6.0mm) and large (>6.0mm). Mesopic pupil size and preoperative and postoperative variables were evaluated using analysis of variance (ANOVA). A regression model was also performed to determine the correlation between mean spherical equivalent and cylinder and visual symptoms.

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Conditions studied

  • Myopia

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03

In context

Myopia

984 studies on the registry are indexed under Myopia; 210 are open to participants now.

This study's enrollment of 51 is below the median of 80 across 783 interventional studies indexed under Myopia.

Browse Myopia studies →

Lead sponsor

Stanford University is the lead sponsor of 2,117 studies on the registry; 425 are open to participants now.

Of its 259 completed or terminated interventional studies of FDA-regulated products, 197 (76%) have results posted.

Counted across the registry records on this site, refreshed daily.

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Who can participate

Ages eligible
Child (0–17), Adult (18–64), Older adult (65+)
Sexes eligible
All
Accepts healthy volunteers
No

Inclusion criteria

  1. no more than 6.00 D of spherical myopia
  2. no more than 3.00 D of refractive astigmatism
  3. a stable refraction (less than 0.50D per year of sphere or cylinder)
  4. a corneal diameter of less than 11.0 mm to allow for suction ring fixation
  5. discontinuation of soft contact wear at least 7 days prior to preoperative evaluation
  6. visual acuity correctable to at least 20/20
  7. age older than 21 years
  8. ability to participate in follow-up examinations for 12 months after LASIK surgery

Exclusion criteria

Exclusion Criteria:

  1. use of rigid gas permeable contact lens
  2. severe dry eye symptoms
  3. severe blepharitis
  4. anterior segment abnormalities (i.e. cataracts, corneal scarring, or neovascularization within 1 mm of intended ablation zone)
  5. recurrent corneal erosion
  6. severe basement membrane disease
  7. progressive or unstable myopia or keratoconus
  8. unstable corneal mires on central keratometry
  9. corneal thickness in which LASIK procedure would result in less than 250 microns of remaining posterior corneal thickness below the flap postoperatively
  10. baseline standard manifest refraction of more than 0.75 D in sphere power
  11. or a difference of greater than 0.50 D in cylinder power compared with baseline standard cycloplegic refraction
  12. a baseline standard cycloplegic refraction differing more than 0.75 in sphere, 0.50 D in cylinder
  13. have a different type of astigmatism (i.e. with-the-rule) when the cylinder is greater than 0.50D compared to baseline standard cycloplegic refraction
  14. preoperative assessment of ocular topography and/or aberrations indicates that either eye is not suitable candidate for LASIK vision correction procedure (i.e. forme fruste keratoconus
  15. corneal warpage, or pellucid marginal degeneration)
  16. previous intraocular or corneal surgery
  17. history of herpes zoster or simplex keratitis
  18. patients on systemic corticosteroid or immunosuppressive therapy
  19. immunocompromised subjects or clinically significant atopic disease
  20. connective tissue disease
  21. diabetes
  22. steroid responder
  23. macular pathology
  24. pregnant or lactating patients
  25. patients with sensitivity to planned study concomitant medications
  26. patients participating in another ophthalmic drug or device clinical trial
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Study design

Phase
Phase 4
Primary purpose
Treatment
Allocation
Non-randomized
Intervention model
Single group
Masking
None (open label)
Enrollment
51 participants (actual)

Study arms

  • Active comparator
    small

    Procedure: LASIK

  • Active comparator
    medium

    Procedure: LASIK

  • Active comparator
    large

    Procedure: LASIK

Interventions

  • ProcedureLASIK

    laser-assisted in situ keratomileusis

    Also known as: laser-assisted in situ keratomileusis

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Study locations

1 site
  • Stanford University School of Medicine
    Stanford, California 94305, United States
07

Updates

Tracking since Sep 25, 2026
No changes since tracking began. The registry record was last updated on Apr 29, 2009, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
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Registry details

Key details

Study ID
NCT00889941
Lead sponsor
Stanford University
First posted
Apr 29, 2009
Start date
May 2004
Primary completion
Nov 2005
Completion
Nov 2005
Last update
Apr 29, 2009

Study contacts

Annie Chan
sub investigator · Stanford University
Edward E. Manche
principal investigator · Stanford University

Oversight

Data monitoring committee
Yes
View the source record on ClinicalTrials.gov ↗

Not currently enrolling

This study is completed, as verified in Apr 2009. You cannot join it, but the record below documents what was studied.

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