MyopiaSMILE VEPNCT07889752
VEP for Assessment SMILE Visual Quality
An observational study of Myopia, run by yuhao shao at 1 site in China.
Trial summary
To evaluate the subjective and objective postoperative visual quality employing pattern visual evoked potential (P-VEP) following small incision lenticule extraction (SMILE). Read more about this study
- Who is it for?
- Ages 18 to 50 years
- Conditions the study is for
- Myopia
- What is being tested?
- small incision lenticule extraction (SMILE)
- Type of treatment
- Surgery or procedure
- How many people
- 84 participants
- Where
- 1 siteChina
- Study dates
- 1 Oct 2021to 30 May 2024
- How long will I take part?
- 6 Months
- Phase
- Observational
- Are there results?
- None posted in the registry
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 18 to 50 years
- All sexes
- No healthy volunteers
- Adult
Study population: hey were divided into three age groups: the < 26 years group, the 26-35 years group, and the > 35 years group. All participants underwent SMILE surgery performed by an experienced surgeon and received follow-up at 1 week, 1 month, 3 months, and 6 months after SMILE.
Who may be able to join
- Patients with refractive errors who were scheduled to undergo SMILE surgery were selected.Each surgical group was further divided according to age into groups of the < 26 years group, the 26-35 years group, and the > 35 years group. There were no significant differences in gender, equivalent spherical diopter (SE), optical zone, and preoperative best corrected visual acuity among the groups.
Who cannot join
- The nearsightedness has increased by more than 1D in the past two years. Severe dry eye syndrome, keratoconus, glaucoma, history of eye surgery, severe systemic connective tissue or autoimmune diseases
Trial locations and contacts
1 site in 1 country.
China1 site
Shanghai Tenth People's Hospital
Shanghai, Shanghai Municipality, 200072
About this study
Official title: Employing Pattern Visual Evoked Potential for the Assessment of Visual Quality After Small Incision Lenticule Extraction
To evaluate the subjective and objective postoperative visual quality employing pattern visual evoked potential (P-VEP) following small incision lenticule extraction (SMILE).
- Conditions
- Myopia
- Being tested
- small incision lenticule extraction (SMILE)
- Keywords
- myopia, SMILE, VEP, cs, qov
- Medical subject headings
- Myopia
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
small incision lenticule extraction (SMILE)Procedure or surgery
The SMILE procedure was conducted by a proficient surgeon utilizing the VisuMax 500 femtosecond laser (Carl Zeiss Meditec AG, Jena, Germany). The thickness of the cap was set to range from 110 to 120 μm, with a diameter of 7.5 mm, and the width of the incision was 2.00 mm. The optical zone was between 6.3 and 6.8 mm. All the patients had successful operations with no complications.
| Study group | Role | What they receive |
|---|---|---|
| <26 years who under small incision lenticule extraction (SMILE) | patients were enrolled in this study and stratified into three age groups by age Receives: Procedure: small incision lenticule extraction (SMILE) | |
| 26-35 years who under small incision lenticule extraction (SMILE) | patients who under small incision lenticule extraction (SMILE) were enrolled in this study and stratified into three age groups by age Receives: Procedure: small incision lenticule extraction (SMILE) | |
| >35 years who under small incision lenticule extraction (SMILE) | patients who under small incision lenticule extraction (SMILE) were enrolled in this study and stratified into three age groups by age Receives: Procedure: small incision lenticule extraction (SMILE) |
What is being measured
The primary outcome is the main question the study is designed to answer.
Ocular aberration measurements
Data collection involved consecutive corneal topography assessments using the Orbscan II device (Bausch \& Lomb). Subsequently, ocular aberration evaluations were conducted with a Hartmann-Shack aberrometer (Zywave, Bausch \& Lomb). The ocular aberration data analysis, including high order aberration (HOA), spherical aberration (SA), and coma, was based on a pupil diameter of 6mm.
Measured: Before the operation, 1 week after the operation, 1 month after the operation, 3 months after the operation, 6 months after the operation
Contrast sensitivity evaluations
CS assessments were performed employing the CSV-1000E (Vector Vision Co., Greenville, Ohio, USA) both prior to surgery and at 1 week, 1 month, 3 months, and 6 months post-surgery. Evaluations were conducted under photopic and mesopic conditions across spatial frequencies of 3, 6, 12, and 18 cycles per degree (cpd).
Measured: Before the operation, 1 week after the operation, 1 month after the operation, 3 months after the operation, 6 months after the operation
Visual evoked potential measurements
The Pattern Visual Evoked Potential (P-VEP) test was conducted using the ROLAND visual electrodiagnostic test system (Germany). Testing took place in a dark, soundproof room where patients were seated comfortably one meter away from the screen. Patients were encouraged to relax and concentrate on the central fixation light throughout the examination. Pattern-reversal VEP acquisition followed International Society for Clinical Electrophysiology of Vision (ISCEV) recommendations7. The VEP was elicited using two check sizes (1° and 15'). N75 peak time, P100 peak time, and P100 amplitude were measured by 3 technicians, and the final value was the average of the 3 measurements.
Measured: Before the operation, 1 week after the operation, 1 month after the operation, 3 months after the operation, 6 months after the operation
Secondary outcomes (1)
Quality of vision questionnaires
The Quality of Vision (QoV) Questionnaire was translated into Chinese and completed by patients prior to surgery, as well as 1 week, 1 month, 3 months, and 6 months post-surgery.
Measured: Before the operation, 1 week after the operation, 1 month after the operation, 3 months after the operation, 6 months after the operation
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted22 Oct 2026
- Study start1 Oct 2021
- Primary completion30 May 2024
- Study completion30 May 2024
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.
- 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
- Observational
- Observational model
- Case-control
- Time perspective
- Prospective
- Enrolment
- 84 participants (actual)
- Target duration
- 6 Months
Sponsor and investigators
- Lead sponsor
- yuhao shao
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor-investigator, yuhao shao, Tongji University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07889752
- Sponsor's protocol ID
- 21VEP
- Other IDs
- YNCR2C004
- Acronym
- SMILE VEP
- Status last verified
- Oct 2026
- First submitted
- 15 Oct 2026
- Last updated
- 27 Oct 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided
Study at a glance
From the registry record, last updated by the sponsor on 27 Oct 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Employing Pattern Visual Evoked Potential for the Assessment of Visual Quality After Small Incision Lenticule Extraction
- ClinicalTrials.gov ID
- NCT07889752
- Acronym / sponsor ID
- SMILE VEP / 21VEP
- Conditions
- Myopia
- Keywords
- myopia, SMILE, VEP, cs, qov
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 84 participants (actual)
- Lead sponsor
- yuhao shaoUniversity, hospital or other
- Study start
- 1 Oct 2021 (actual)
- Primary completion
- 30 May 2024 (actual)
- Study completion
- 30 May 2024 (actual)
- First posted
- 22 Oct 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.
To evaluate the subjective and objective postoperative visual quality employing pattern visual evoked potential (P-VEP) following small incision lenticule extraction (SMILE).
Study design
- Observational model
- Case-control
- Time perspective
- Prospective
- Target follow-up
- 6 Months
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| <26 years who under small incision lenticule extraction (SMILE) | – | Procedure: small incision lenticule extraction (SMILE)patients were enrolled in this study and stratified into three age groups by age |
| 26-35 years who under small incision lenticule extraction (SMILE) | – | Procedure: small incision lenticule extraction (SMILE)patients who under small incision lenticule extraction (SMILE) were enrolled in this study and stratified into three age groups by age |
| >35 years who under small incision lenticule extraction (SMILE) | – | Procedure: small incision lenticule extraction (SMILE)patients who under small incision lenticule extraction (SMILE) were enrolled in this study and stratified into three age groups by age |
Who may qualify
- Ages
- 18 to 50 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult
- Study population
- hey were divided into three age groups: the < 26 years group, the 26-35 years group, and the > 35 years group. All participants underwent SMILE surgery performed by an experienced surgeon and received follow-up at 1 week, 1 month, 3 months, and 6 months after SMILE.
Key inclusion criteria (1 listed)
- Patients with refractive errors who were scheduled to undergo SMILE surgery were selected.Each surgical group was further divided according to age into groups of the < 26 years group, the 26-35 years group, and the > 35 years group. There were no significant differences in gender, equivalent spherical diopter (SE), optical zone, and preoperative best corrected visual acuity among the groups.
Key exclusion criteria (1 listed)
- The nearsightedness has increased by more than 1D in the past two years. Severe dry eye syndrome, keratoconus, glaucoma, history of eye surgery, severe systemic connective tissue or autoimmune diseases
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 |
|---|---|---|
| small incision lenticule extraction (SMILE)The SMILE procedure was conducted by a proficient surgeon utilizing the VisuMax 500 femtosecond laser (Carl Zeiss Meditec AG, Jena, Germany). The thickness of the cap was set to range from 110 to 120 μm, with a diameter of 7.5 mm, and the width of the incision was 2.00 mm. The optical zone was between 6.3 and 6.8 mm. All the patients had successful operations with no complications. | Procedure or surgery | 26-35 years who under small incision lenticule extraction (SMILE), <26 years who under small incision lenticule extraction (SMILE), >35 years who under small incision lenticule extraction (SMILE) |
Primary outcome
Ocular aberration measurements
Time frame: Before the operation, 1 week after the operation, 1 month after the operation, 3 months after the operation, 6 months after the operation
Data collection involved consecutive corneal topography assessments using the Orbscan II device (Bausch \& Lomb). Subsequently, ocular aberration evaluations were conducted with a Hartmann-Shack aberrometer (Zywave, Bausch \& Lomb). The ocular aberration data analysis, including high order aberration (HOA), spherical aberration (SA), and coma, was based on a pupil diameter of 6mm.
Contrast sensitivity evaluations
Time frame: Before the operation, 1 week after the operation, 1 month after the operation, 3 months after the operation, 6 months after the operation
CS assessments were performed employing the CSV-1000E (Vector Vision Co., Greenville, Ohio, USA) both prior to surgery and at 1 week, 1 month, 3 months, and 6 months post-surgery. Evaluations were conducted under photopic and mesopic conditions across spatial frequencies of 3, 6, 12, and 18 cycles per degree (cpd).
Visual evoked potential measurements
Time frame: Before the operation, 1 week after the operation, 1 month after the operation, 3 months after the operation, 6 months after the operation
The Pattern Visual Evoked Potential (P-VEP) test was conducted using the ROLAND visual electrodiagnostic test system (Germany). Testing took place in a dark, soundproof room where patients were seated comfortably one meter away from the screen. Patients were encouraged to relax and concentrate on the central fixation light throughout the examination. Pattern-reversal VEP acquisition followed International Society for Clinical Electrophysiology of Vision (ISCEV) recommendations7. The VEP was elicited using two check sizes (1° and 15'). N75 peak time, P100 peak time, and P100 amplitude were measured by 3 technicians, and the final value was the average of the 3 measurements.
1 secondary outcome
Quality of vision questionnaires
Time frame: Before the operation, 1 week after the operation, 1 month after the operation, 3 months after the operation, 6 months after the operation
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 27 Oct 2026.
- Individual participant dataSharing planned: Undecided
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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. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Myopia, run by yuhao shao at 1 site in China.
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 1 inclusion and 1 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: finished, as of the sponsor's last update on 27 Oct 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 China. 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.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Ocular aberration measurements (time frame: Before the operation, 1 week after the operation, 1 month after the operation, 3 months after the operation, 6 months after the operation). The study lists 3 primary outcomes in all. 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 27 Oct 2026.