MyopiaPhase 4NCT07721714
SMILE Surgery in One Eye Compared to Ray Tracing-guided LASIK Surgery in the Fellow Eye
A Phase 4 study testing Ray tracing guided LASIK surgery in people with Myopia and Astigmatism, run by Stanford University at 1 site in United States.
Trial summary
Participants will undergo LASIK surgery in one eye using ray tracing guided technology in one eye and LASIK surgery in the other eye using wavefront guided technology. We are comparing outcomes between the two technologies as measured by self reported quality of vision and quality of life outcomes using validated… Read more about this study
- Who is it for?
- Ages 22 to 59 years
- Conditions the study is for
- Myopia, Astigmatism
- What is being tested?
- Ray tracing guided LASIK surgery
- Type of treatment
- Medical device
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 62 participants
- Where
- 1 siteUnited States
- Study dates
- 5 Aug 2026to 31 Jul 2029
- Phase
- Phase 4
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 22 to 59 years
- All sexes
- No healthy volunteers
- Adult
Who may be able to join
- Subjects age 22 and older with healthy eyes. Nearsightedness between -1.00 diopters and -8.00 diopters.
- Subjects with less than or equal to 3.00 diopters of astigmatism.
Who cannot join
- Subjects under the age of 22. Subjects with excessively thin corneas. Subjects with topographic evidence of keratoconus. Subjects with ectactic eye disorders. Subjects with autoimmune diseases. Subjects who are pregnant or nursing. Subjects must have similar levels of nearsightedness in each eye. They can not be more than 1.5 diopter of difference between eyes.
- Subjects with more than 3.00 diopters of astigmatism Subjects must have similar levels of astigmatism in each eye. They can not have more than 0.75 diopters of difference between eyes.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
United States1 site, 1 recruiting
- Recruiting
Byers Eye Institute
Palo Alto, California, 94303
Edward Manche E Manche, MD, 650-498-7020, cornea@stanford.edu
Edward E Manche, MD
About this study
Official title: A Prospective Randomized Comparison of SMILE Surgery to Ray Tracing-Guided LASIK Surgery
Participants will undergo LASIK surgery in one eye using ray tracing guided technology in one eye and LASIK surgery in the other eye using wavefront guided technology. We are comparing outcomes between the two technologies as measured by self reported quality of vision and quality of life outcomes using validated questionnaires before and after surgery. We will also be comparing outcomes between the two technologies including measurement of low contrast visual acuity,and best spectacle corrected visual acuity.
Read the detailed description
Sixty-two near-sighted study participants at Stanford are planned to undergo treatment in this clinical research trial.
This comparison will be made between both eyes of the same study participant following LASIK and SMILE surgery. One eye will have ray tracing-guided LASIK and their fellow eye treated with SMILE surgery. Both ray tracing-guided LASIK surgery and SMILE surgery have been found to be safe, predictable and effective when used for laser vision correction procedures. Both ray tracing-guided LASIK surgery and SMILE surgery used in this study have been approved for laser vision correction by the United States Food and Drug Administration. Standard refractive outcomes such as uncorrected visual acuity (vision without glasses or contact lenses) and best corrected visual acuity (vision with glasses or contact lenses), and intended vs. achieved postoperative refractions (the accuracy of the LASIK and SMILE procedures) will be evaluated.
Randomization:
The choice of which eye receives ray tracing-guided LASIK surgery and which eye receives SMILE surgery will be randomized (assigned at random) prior to enrollment. Participants will have one eye treated with ray tracing-guided LASIK and your other eye treated with the SMILE surgery. Participants will know which eye is being treated with ray tracing-guided LASIK and which eye will be treated with SMILE surgery. Both ray tracing-guided LASIK and SMILE surgery are FDA-approved procedures. Both procedures are being performed according to the FDA-approved labeling. Participants have a fifty percent chance of having their left eye treated with ray tracing-guided LASIK as their right eye (like making a choice by flipping a coin). Participants will undergo bilateral (both eyes at once) surgery.
Screening and Preoperative Assessment Participants will be partially screened via telephone. We will also ask participants to complete screening by coming to the clinic in person. This screening will include measurements of corneal thickness, the shape of the cornea using corneal topography (measures the shape of the front clear surface of the eye), a slit lamp examination of the eye (a microscope to magnify the cornea) and ocular and medical history.
Participants scheduled to undergo LASIK and SMILE surgery for the correction of myopia (nearsightedness) will be screened for eligibility. Eligible participants will be examined preoperatively to establish a baseline for ocular condition (the general health and glasses prescription of the eyes). Postoperatively, participants will undergo an ophthalmic evaluation (complete eye examination) at regular intervals as specified in this protocol. Re-treatments (a second operation on the same eye for residual nearsightedness, farsightedness and/or astigmatism) will not be allowed during the first twelve months of this study. If you elect to undergo a retreatment of your LASIK surgery prior to the 12-month post-operative visit, the data after the retreatment procedure will be excluded from the study analysis.
Participants eyes will be given a thorough examination at each visit. This examination will include the standard elements of a general eye exam including testing of the eye's vision, contrast acuity testing, examination with the slit lamp and the ophthalmoscope to look at the various parts of the eye and a test of the inner eye's pressure.
- Conditions
- Myopia, Astigmatism
- Being tested
- Ray tracing guided LASIK surgery
- Keywords
- Ray-tracing, LASIK, SMILE
- Medical subject headings
- Myopia, Astigmatism
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Ray tracing guided LASIK surgeryDevice
LASIK
| Study group | Role | What they receive |
|---|---|---|
| Ray tracing guided LASIK surgery | Active comparator | LASIK Receives: Device: Ray tracing guided LASIK surgery |
| SMILE surgery | Active comparator | SMILE Receives: Device: Ray tracing guided LASIK surgery |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in corrected distance visual acuity
The primary endpoint will be the gain in lines of corrected distance visual acuity (CDVA) at the postoperative month three follow-up compared with preoperative baseline.
Measured: Three months
Secondary outcomes (4)
Change in 5 and 25% low contrast CDVA
Change in 5 and 25% low contrast best corrected visual acuity from preoperative to postoperative month three
Measured: Three months
Change in patient self reported quality of vision and life
Will compare preoperative quality of vision and quality of life as measured by the validated Patient Reported Outcomes With LASIK (PROWL) questionnaire to postoperative month three.
Measured: Three months
Corneal epithelial thickness changes
Measure corneal epithelial thickness maps preoperatively and compare changes at postoperative month three
Measured: Three months
Change in higher order aberrations
Will measure preoperative higher order aberrations using wavefront aberrometry and compare to postoperative month three measurements
Measured: Three months
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted23 Jul 2026
- Study start5 Aug 2026
- Primary completion31 Dec 2028 (estimated)
- Study completion31 Jul 2029 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for MyopiaStudies of the same condition, open and under way.
- More trials run by Stanford UniversityThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 4
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Single group
- Model description
- Prospective, randomized, contralateral fellow eye study
- Masking
- None (open label)
- Enrolment
- 62 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Stanford University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Edward E. Manche, Stanford University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07721714
- Sponsor's protocol ID
- 79951
- Other IDs
- 359910
- Status last verified
- Aug 2026
- First submitted
- 18 Jul 2026
- Last updated
- 26 Aug 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- Yes
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 26 Aug 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Prospective Randomized Comparison of SMILE Surgery to Ray Tracing-Guided LASIK Surgery
- ClinicalTrials.gov ID
- NCT07721714
- Acronym / sponsor ID
- 79951
- Conditions
- Myopia, Astigmatism
- Keywords
- Ray-tracing, LASIK, SMILE
- Phase
- Phase 4
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 62 participants (estimated)
- Lead sponsor
- Stanford UniversityUniversity, hospital or other
- Study start
- 5 Aug 2026 (actual)
- Primary completion
- 31 Dec 2028 (estimated)
- Study completion
- 31 Jul 2029 (estimated)
- First posted
- 23 Jul 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Participants will undergo LASIK surgery in one eye using ray tracing guided technology in one eye and LASIK surgery in the other eye using wavefront guided technology. We are comparing outcomes between the two technologies as measured by self reported quality of vision and quality of life outcomes using validated questionnaires before and after surgery. We will also be comparing outcomes between the two technologies including measurement of low contrast visual acuity,and best spectacle corrected visual acuity.
Detailed description
Sixty-two near-sighted study participants at Stanford are planned to undergo treatment in this clinical research trial.
This comparison will be made between both eyes of the same study participant following LASIK and SMILE surgery. One eye will have ray tracing-guided LASIK and their fellow eye treated with SMILE surgery. Both ray tracing-guided LASIK surgery and SMILE surgery have been found to be safe, predictable and effective when used for laser vision correction procedures. Both ray tracing-guided LASIK surgery and SMILE surgery used in this study have been approved for laser vision correction by the United States Food and Drug Administration. Standard refractive outcomes such as uncorrected visual acuity (vision without glasses or contact lenses) and best corrected visual acuity (vision with glasses or contact lenses), and intended vs. achieved postoperative refractions (the accuracy of the LASIK and SMILE procedures) will be evaluated.
Randomization:
The choice of which eye receives ray tracing-guided LASIK surgery and which eye receives SMILE surgery will be randomized (assigned at random) prior to enrollment. Participants will have one eye treated with ray tracing-guided LASIK and your other eye treated with the SMILE surgery. Participants will know which eye is being treated with ray tracing-guided LASIK and which eye will be treated with SMILE surgery. Both ray tracing-guided LASIK and SMILE surgery are FDA-approved procedures. Both procedures are being performed according to the FDA-approved labeling. Participants have a fifty percent chance of having their left eye treated with ray tracing-guided LASIK as their right eye (like making a choice by flipping a coin). Participants will undergo bilateral (both eyes at once) surgery.
Screening and Preoperative Assessment Participants will be partially screened via telephone. We will also ask participants to complete screening by coming to the clinic in person. This screening will include measurements of corneal thickness, the shape of the cornea using corneal topography (measures the shape of the front clear surface of the eye), a slit lamp examination of the eye (a microscope to magnify the cornea) and ocular and medical history.
Participants scheduled to undergo LASIK and SMILE surgery for the correction of myopia (nearsightedness) will be screened for eligibility. Eligible participants will be examined preoperatively to establish a baseline for ocular condition (the general health and glasses prescription of the eyes). Postoperatively, participants will undergo an ophthalmic evaluation (complete eye examination) at regular intervals as specified in this protocol. Re-treatments (a second operation on the same eye for residual nearsightedness, farsightedness and/or astigmatism) will not be allowed during the first twelve months of this study. If you elect to undergo a retreatment of your LASIK surgery prior to the 12-month post-operative visit, the data after the retreatment procedure will be excluded from the study analysis.
Participants eyes will be given a thorough examination at each visit. This examination will include the standard elements of a general eye exam including testing of the eye's vision, contrast acuity testing, examination with the slit lamp and the ophthalmoscope to look at the various parts of the eye and a test of the inner eye's pressure.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 2
- Model description
- Prospective, randomized, contralateral fellow eye study
| Arm | Type | Receives |
|---|---|---|
| Ray tracing guided LASIK surgery | Active comparator | Device: Ray tracing guided LASIK surgeryLASIK |
| SMILE surgery | Active comparator | Device: Ray tracing guided LASIK surgerySMILE |
Who may qualify
- Ages
- 22 to 59 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult
Key inclusion criteria (2 listed)
- Subjects age 22 and older with healthy eyes. Nearsightedness between -1.00 diopters and -8.00 diopters.
- Subjects with less than or equal to 3.00 diopters of astigmatism.
Key exclusion criteria (2 listed)
- Subjects under the age of 22. Subjects with excessively thin corneas. Subjects with topographic evidence of keratoconus. Subjects with ectactic eye disorders. Subjects with autoimmune diseases. Subjects who are pregnant or nursing. Subjects must have similar levels of nearsightedness in each eye. They can not be more than 1.5 diopter of difference between eyes.
- Subjects with more than 3.00 diopters of astigmatism Subjects must have similar levels of astigmatism in each eye. They can not have more than 0.75 diopters of difference between eyes.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Ray tracing guided LASIK surgeryLASIK | Device | Ray tracing guided LASIK surgery, SMILE surgery |
Primary outcome
Change in corrected distance visual acuity
Time frame: Three months
The primary endpoint will be the gain in lines of corrected distance visual acuity (CDVA) at the postoperative month three follow-up compared with preoperative baseline.
4 secondary outcomes
Change in 5 and 25% low contrast CDVA
Time frame: Three months
Change in patient self reported quality of vision and life
Time frame: Three months
Corneal epithelial thickness changes
Time frame: Three months
Change in higher order aberrations
Time frame: Three months
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 26 Aug 2026.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 4 study testing Ray tracing guided LASIK surgery in people with Myopia and Astigmatism, run by Stanford University at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 2 inclusion and 2 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 26 Aug 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 4 studies take place after a treatment is approved, to learn more about its long-term benefits and risks in everyday use.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Edward E Manche, MD (1-650-498-7020, edward.manche@stanford.edu), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change in corrected distance visual acuity (time frame: Three months). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 26 Aug 2026.