An interventional study of Device-assisted cyclotorsion control during SMILE and Manual limbal marking-guided cyclotorsion adjustment during SMILE in Myopia and Refractive Ametropia, sponsored by Zhongshan Ophthalmic Center, Sun Yat-sen University. Not yet recruiting at 1 site in China. Open to participants aged 18 Years to 40 Years. Per ClinicalTrials.gov, last updated 2026-07-15.
Sponsored by Zhongshan Ophthalmic Center, Sun Yat-sen University · Not applicable, Interventional, and Treatment
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Among 24 studies in Myopia by Zhongshan Ophthalmic Center, Sun Yat-sen University — 12 open to participants now, 14 under way, none of them phase 3. Myopia · Zhongshan Ophthalmic Center, Sun Yat-sen University.
Among the 24 studies in Myopia by Zhongshan Ophthalmic Center, Sun Yat-sen University, this one is the 16th largest by planned enrollment of the 17 interventional ones that give a count, is one of 5 that started in 2026, is one of 17 with no phase, reaches primary completion later than 11 of the 13 other live ones, and was the 22nd registered.
1,160 studies on the registry are indexed under Myopia; 225 are open to participants now.
Browse Myopia studies →12 of the 24 studies in Myopia by Zhongshan Ophthalmic Center, Sun Yat-sen University are open now, in 1 country. Recruiting first, the newest first:
Zhongshan Ophthalmic Center, Sun Yat-sen University · Sites in China
Ages 6–18 · Healthy volunteers
Zhongshan Ophthalmic Center, Sun Yat-sen University · Sites in China
Ages 18–40
Zhongshan Ophthalmic Center, Sun Yat-sen University · Sites in China
Ages 18–40
Zhongshan Ophthalmic Center, Sun Yat-sen University · Sites in China
Ages 3–18 · Healthy volunteers
Zhongshan Ophthalmic Center, Sun Yat-sen University
Ages 8–13
By country, each count listing its studies:
Of the 122 Myopia studies recruiting now, 19 (16%) set no upper age limit and 102 (84%) stop at 75 or younger; 86 take children under 18; 53 take healthy volunteers.
This study: 18 Years to 40 Years · all sexes · no healthy volunteers.
The full table on the hub →This tab as a report to print or save as PDF → With an account.
24 studies; the count open now beside each. This study's row is marked.
First in 2016; this study’s year is marked. 5 started in 2026.
By drug class, each counting the studies that test any of its medicines:
This study's planned enrollment of 52 is below the median of 78 across 923 interventional studies indexed under Myopia.
Median enrollment 194 across the 17 interventional studies, 1,000 across the 7 observational. Of the 4 that completed or were terminated, 0 (0%) have results posted.
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Zhongshan Ophthalmic Center, Sun Yat-sen University is the lead sponsor of 165 studies on the registry; 81 are open to participants now.
4 of the studies in Myopia by Zhongshan Ophthalmic Center, Sun Yat-sen University that are under way reach primary completion within a year, 0 of them phase 3. Phase 3 first, then by date:
| Study | Primary completion |
|---|---|
| NCT06667037Zhongshan Ophthalmic Center, Sun Yat-sen UniversityOrthokeratology and 0.01% Atropine Sequential Treatment for Myopia Control | 2026-12-31 |
| NCT07512102Zhongshan Ophthalmic Center, Sun Yat-sen UniversityComparison of Low- Versus High-Level Angle Kappa Compensation Strategies in SMILE Using the VisuMax 800: A Randomized Clinical Trial | 2027-05-30 |
| NCT07512115Zhongshan Ophthalmic Center, Sun Yat-sen UniversityThe Impact of 'A Miss Is as Good as a Mile': Is Compensation Necessary for Minimal Ocular Deviation in Myopic Laser Surgery? | 2027-05-30 |
| NCT07696468Zhongshan Ophthalmic Center, Sun Yat-sen UniversityComparison of Two Rotational Alignment Methods for Astigmatism Correction in SMILE Surgery | 2027-06-30 |
Add all 4 to your calendar (.ics) → With an account.
Among the 24 studies in Myopia by Zhongshan Ophthalmic Center, Sun Yat-sen University, from their registry updates:
This tab as a report to print or save as PDF → With an account.
Small incision lenticule extraction (SMILE) is a commonly used corneal refractive procedure for correcting myopia and myopic astigmatism. During astigmatism correction, eye rotation between the upright examination position and the supine surgical position may affect the alignment of the astigmatic treatment axis and may contribute to residual astigmatism after surgery.
Manual limbal marking is a commonly used method to guide cyclotorsion adjustment during refractive surgery. OcuLign is an assisted cyclotorsion control function of the VISUMAX 800 platform that helps identify ocular rotation and guide axis alignment during SMILE. However, direct clinical evidence comparing OcuLign-assisted cyclotorsion control with manual limbal marking during SMILE is limited.
This study is a single-center, prospective, randomized, masked, contralateral-eye non-inferiority trial. Adults aged 18 to 40 years with stable myopia and astigmatism who plan to undergo bilateral SMILE surgery will be enrolled. In each participant, one eye will receive SMILE with OcuLign-assisted cyclotorsion control, and the fellow eye will receive SMILE with manual limbal marking-guided cyclotorsion adjustment. The treatment assigned to the right eye will be determined by randomization.
The primary objective is to compare residual refractive astigmatism at 3 months after surgery between the two methods. Secondary outcomes include visual acuity, refractive predictability and stability, astigmatism vector analysis, higher-order aberrations, contrast sensitivity, patient-reported quality of vision, overall satisfaction, and safety outcomes. Participants will be followed for approximately 6 months after surgery.
Accurate alignment of the astigmatic treatment axis is an important factor in the correction of myopic astigmatism during small incision lenticule extraction (SMILE). Cyclotorsion may occur when a patient changes from the upright preoperative examination position to the supine surgical position, and may also be influenced by fixation, head position, and suction during surgery. Inadequate compensation for ocular rotation may reduce astigmatic correction accuracy and contribute to postoperative residual astigmatism.
Manual limbal marking is a commonly used method for cyclotorsion adjustment in corneal refractive surgery. This method is clinically feasible and widely used, but it depends on preoperative marking and intraoperative manual judgment. Marking clarity, ocular surface conditions, patient cooperation, and surgeon experience may affect the accuracy and reproducibility of the adjustment. OcuLign is an assisted cyclotorsion control function of the VISUMAX 800 platform that helps identify ocular rotation and guide axis alignment during SMILE. This study is designed to compare OcuLign-assisted cyclotorsion control with manual limbal marking-guided cyclotorsion adjustment during SMILE.
This trial uses a prospective, randomized, contralateral-eye non-inferiority design. Each participant will undergo bilateral SMILE surgery. One eye will be assigned to OcuLign-assisted cyclotorsion control, and the fellow eye will be assigned to manual limbal marking-guided cyclotorsion adjustment, according to a prespecified randomization sequence. This paired-eye design is intended to reduce inter-individual variability in refractive characteristics, healing response, and subjective visual perception. Apart from the method of cyclotorsion adjustment, surgical parameters, lenticule design, suction procedure, postoperative medication, and follow-up schedule will be kept consistent between the two eyes.
Participants and postoperative outcome assessors will be masked to the eye-level treatment assignment whenever feasible. The operating surgeon cannot be masked because the assigned cyclotorsion adjustment method must be performed during surgery. Postoperative assessments will be conducted at predefined follow-up visits through approximately 6 months after surgery.
The primary comparison will evaluate whether OcuLign-assisted cyclotorsion control is non-inferior to manual limbal marking-guided adjustment in terms of residual refractive astigmatism at 3 months after surgery. Secondary assessments will evaluate visual acuity, refractive predictability and stability, astigmatism vector parameters, higher-order aberrations, contrast sensitivity, patient-reported quality of vision, satisfaction, and safety. Safety monitoring will include loss of corrected distance visual acuity and postoperative adverse events.
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Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
One eye of each participant will undergo SMILE using OcuLign-assisted cyclotorsion control on the VISUMAX 800 platform. OcuLign will be used intraoperatively to assist in identifying ocular rotation and guiding astigmatic axis alignment. Apart from the cyclotorsion adjustment method, the surgical parameters, lenticule design, suction procedure, postoperative medication, and follow-up schedule will be the same as those used for the fellow eye.
Procedure: Device-assisted cyclotorsion control during SMILE
The fellow eye of each participant will undergo SMILE using manual limbal marking-guided cyclotorsion adjustment. Limbal reference marks will be made in the upright preoperative position, and intraoperative axis alignment will be manually adjusted according to the marks and the surgical reference direction. Apart from the cyclotorsion adjustment method, the surgical parameters, surgical procedure, postoperative medication, and follow-up schedule will be the same as those used for the contralateral eye.
Procedure: Manual limbal marking-guided cyclotorsion adjustment during SMILE
One eye of each participant will undergo SMILE using device-assisted cyclotorsion control with the OcuLign function of the VISUMAX 800 platform. During surgery, OcuLign will assist in identifying ocular rotation and guiding astigmatic axis alignment. Apart from the cyclotorsion adjustment method, the surgical parameters, lenticule design, suction procedure, postoperative medication, and follow-up schedule will be the same as those used for the fellow eye.
Also known as: OcuLign-assisted cyclotorsion control, VISUMAX 800 OcuLign
The fellow eye of each participant will undergo SMILE using manual limbal marking-guided cyclotorsion adjustment. Limbal reference marks will be made in the upright preoperative position, and intraoperative axis alignment will be manually adjusted according to the limbal marks and the surgical reference direction. Apart from the cyclotorsion adjustment method, the surgical parameters, surgical procedure, postoperative medication, and follow-up schedule will be the same as those used for the contralateral eye.
Residual refractive astigmatism
Residual refractive astigmatism will be measured as the absolute manifest cylinder power in diopters at 3 months after SMILE. The primary analysis will compare residual refractive astigmatism between eyes treated with OcuLign-assisted cyclotorsion control and eyes treated with manual limbal marking-guided cyclotorsion adjustment to evaluate non-inferiority.
Time frame: 3 months after surgery
Astigmatic correction predictability
Astigmatic correction predictability will be assessed as the proportion of eyes with postoperative residual manifest cylinder within predefined thresholds, including ≤0.25 D, ≤0.50 D, and ≤1.00 D.
Time frame: 1 month, 3 months, and 6 months after surgery
Astigmatic Correction Assessed by Alpins Vector Analysis
Postoperative astigmatic correction will be assessed using the Alpins vector analysis method based on refractive cylinder and axis data. This outcome will be used to describe the overall accuracy of astigmatism correction after surgery.
Time frame: 3 months after surgery
Visual acuity
Uncorrected distance visual acuity and corrected distance visual acuity will be measured using standardized visual acuity charts and recorded as logMAR visual acuity. Visual acuity-derived performance will also be summarized using the safety index and efficacy index, calculated from the same visual acuity measurements. The safety index is defined as postoperative corrected distance visual acuity divided by preoperative corrected distance visual acuity, and the efficacy index is defined as postoperative uncorrected distance visual acuity divided by preoperative corrected distance visual acuity.
Time frame: 1 month, 3 months, and 6 months after surgery
Manifest refraction
Postoperative manifest refraction will include sphere, cylinder, and spherical equivalent measured by standard manifest refraction.
Time frame: 1 month, 3 months, and 6 months after surgery
Refractive accuracy
Refractive accuracy will be assessed as the proportion of eyes with postoperative spherical equivalent within predefined ranges of the target refraction, including within ±0.25 D, ±0.50 D, and ±1.00 D.
Time frame: 1 month, 3 months, and 6 months after surgery
Refractive stability
Refractive stability will be assessed as the change in manifest spherical equivalent refraction between postoperative follow-up visits.
Time frame: 1 month to 6 months after surgery
Higher-Order Wavefront Aberration Assessment
Higher-order wavefront aberrations will be measured using wavefront aberrometry under standardized conditions to assess postoperative optical quality.
Time frame: 1 month, 3 months, and 6 months after surgery
Contrast sensitivity
Contrast sensitivity will be measured under standardized conditions using the CSV-1000 contrast sensitivity testing system at multiple spatial frequencies, including 3, 6, 12, and 18 cycles per degree. The area under the log contrast sensitivity function may be calculated as a summary measure when appropriate.
Time frame: 3 months after surgery
Quality of Vision score
Subjective visual symptoms will be assessed using the Quality of Vision questionnaire, which evaluates the frequency, severity, and bothersome nature of visual disturbances such as glare, halos, and double vision. Higher scores indicate worse subjective visual quality.
Time frame: 3 months after surgery
Overall visual satisfaction score
Overall visual satisfaction will be assessed using a 5-point Likert rating scale. Scores range from 1 to 5, with higher scores indicating greater satisfaction.
Time frame: 3 months after surgery
Plan to share: No
Start is estimated for Jul 2026; primary completion for Jun 2027, 11 months later.
Of 200 non-industry interventional studies with no phase under Myopia, half reached primary completion within 25 months of starting (the median), counting those still running; a quarter within 11 and three quarters within 44. This study's planned 11 months is below that.
Counting every sponsor, half of 434 studies reached it within 14 months; a quarter within 3 and three quarters within 34.
How these figures are worked out, and which studies are left out of them.
This study is not yet recruiting, as verified in Jul 2026. You cannot join it, but the record below documents what was studied.
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Zhongshan Ophthalmic Center, Sun Yat-sen University →