Wavefront-guided Photorefractive Keratectomy (PRK) Versus Wavefront-guided Lasik for Myopia

• Improvement in uncorrected visual acuity [ Time Frame: Baseline to one year ] [ Designated as safety issue: No ]
  
• Changes in best spectacle corrected visual acuity [ Time Frame: Baseline to one year ] [ Designated as safety issue: Yes ]
  
• Changes in 25 and 5% low contrast acuity [ Time Frame: baseline to one year ] [ Designated as safety issue: Yes ]
  

• Changes in quality of vision [ Time Frame: baseline to one year ] [ Designated as safety issue: Yes ]
  
• Comparison of dry eye signs and symptoms between LASIK and PRK [ Time Frame: baseline to one year ] [ Designated as safety issue: Yes ]
  
• Changes in quality of vision [ Time Frame: baseline to one year ] [ Designated as safety issue: No ]
  
• Changes in higher order aberrations [ Time Frame: Baseline to one year ] [ Designated as safety issue: No ]
  

Procedure: Photorefractive keratectomy
One eye undergoes wavefront-guided PRK with the Visx S4 CustomVue excimer laser.
Other Name: PRK, CustomVue, Wavefront-guided
Procedure: Laser in-situ keratomileusis
One eye undergoes wavefront-guided LASIK using the Visx S4 excimer laser.
Other Name: LASIK, CustomVue, Visx, Intralase FS60

This is a research study comparing the outcomes of LASIK surgery to PRK surgery for nearsightedness when using the two different procedures. You will have one eye treated with LASIK using the Intralase FS laser and your other eye treated with PRK. You will be one of 100 sighted patients at Stanford to undergo treatment in this clinical research trial. This will be a prospective, randomized, research study in which up to 200 consecutive eyes scheduled to undergo excimer laser in situ keratomileusis (LASIK) in one eye and photorefractive keratectomy (PRK) in the fellow eye for the correction of myopia (nearsightedness) with or without astigmatism will be enrolled. The choice of which eye receives LASIK and which eye receives PRK will be randomized prior to enrollment. Randomization will be done according to a randomization schedule. You will know which eye is being treated with which procedure. The randomization will determine only whether your right or left eye is treated with the LASIK procedure. The other eye will be treated with PRK. You have a fifty percent chance of having your left eye treated with LASIK as your right eye. Subjects will undergo either bilateral (both eyes at once) wavefront (a more precise custom laser system) guided LASIK and PRK treatments using the VISX Star S4 excimer laser. All subjects will be followed for one year after the vision correction procedure. Subjects scheduled to undergo LASIK and PRK for the correction of myopia (nearsightedness) with or without astigmatism will be screened for eligibility. Eligible subjects will be examined preoperatively to establish a baseline for ocular condition (the general health and glasses prescription of the eyes). Postoperatively, subjects will undergo an ophthalmic evaluation (complete eye examination) at regular intervals as specified in this protocol. Retreatments (a second operation on the same eye for residual nearsightedness) will not be allowed during the first six months of this study. If you elect to undergo a retreatment of your LASIK or PRK surgery prior to the 6-month post-operative visit, the retreated eye will be exited from the study as of the retreatment date.

Any significant new finding developed during the course of the research which may relate to the subject's willingness to continue participation will be provided to the subject or subject's representative in a timely manner.