The Influence of Axial Length on Visual Quality Following SMILE Surgery in Patients with High Myopia

March 20, 2025 updated by: yuhao shao
This retrospective study aimed to investigate the subjective and objective visual outcomes following Small Incision Lenticule Extraction (SMILE) surgery in high myopic patients with varying axial lengths (AL).

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

The study enrolled 113 highly myopic patients (202 eyes) who underwent SMILE surgery at Shanghai's Tenth People's Hospital. Patients were classified into three groups based on the axial length before surgery: Group A (AL < 26 mm, 62 eyes), Group B (26 mm ≤ AL < 27 mm, 88 eyes), and Group C (AL ≥ 27 mm, 52 eyes). Preoperative and postoperative evaluations included uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), equivalent spherical error(SE), and corneal high order aberration. Subjective visual quality was assessed using the Quality of Vision (QoV) questionnaire.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Observational

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
113

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • China
    • Shanghai
      • Shanghai, Shanghai, China, 200000
        • Shanghai Tenth People's Hospital

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult

Accepts Healthy Volunteers

Yes

Sampling Method

Non-Probability Sample

Study Population

A total of 113 high myopic patients (202 eyes) of Shanghai's Tenth People's Hospital were enroled in this prospective, non-randomized study conducted from July 2021 to September 2023.

Description

Inclusion Criteria:

  • manifest refraction spherical equivalent refraction exceeding -6.00D;
  • stable myopia for a duration of at least 2 years;
  • corrected distance visual acuity of at least 20/25;
  • annual myopic spherical equivalent increment less than - 0.50 D.

Exclusion Criteria:

  • a history of moderate to severe dry eye as well as any ocular or systemic disease.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort

Group / Cohort

A group or subgroup of participants in an observational study that is assessed for biomedical or health outcomes.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
AL < 26 mm
high myopic patients with axial lengths < 26 mm
Other: This study does not involve any interventions
This study does not involve any interventions
26 mm ≤ AL < 27 mm
high myopic patients with 26 mm ≤ axial lengths < 27 mm
Other: This study does not involve any interventions
This study does not involve any interventions
AL ≥ 27 mm
high myopic patients with axial lengths ≥ 27 mm
Other: This study does not involve any interventions
This study does not involve any interventions

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Subjective visual quality
Time Frame: 12 months
The quality of vision (QOV) questionnaire consists of (i) symptom frequency, (ii) severity, and (iii) bothersomeness for (a) glare, (b) halo, (c) starbursts, (d) hazy vision, (e) blurred vision, (f) distortion, (g) multiple images, (h) visual fluctuations, (i) difficulty focusing, and (j) difficulty judging distance or depth perception. Respondents use a scale of 0 to 3, where zero (0) denotes "none," one (1) "a little," two (2) "quite a bit," and three (3) "very much." Furthermore, on a scale from 0 to 10, patients were asked to provide Likert ratings for "daytime" and "nighttime" quality of vision (0 denoting the poorest vision, while 10 indicating the best vision)
12 months

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Refractive results
Time Frame: 12 months
The uncorrected distance visual acuity (UDVA, logMAR), corrected distance visual acuity (CDVA, logMAR), subjective refraction (Diopter), and intraocular pressure (mmHg) were evaluated prior to and 1 year after SMILE.
12 months

Other Outcome Measures

Other Outcome Measures

For clinical trials, a planned measurement described in the protocol that is used to determine the effect of an intervention/treatment on participants. For observational studies, a measurement or observation that is used to describe patterns of diseases or traits, or associations with exposures, risk factors, or treatment. Types of outcome measures include primary outcome measure and secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Ocular high-order aberrations
Time Frame: 12 months
Corneal aberration measurements were performed using a Scheimpflug tomography system (Pentacam; Oculus GmbH, Wetzlar, Germany). Images of the highest quality (designated as OK) were selected for analysis. The coefficients for a standardized diameter of 8 mm were examined, followed by an assessment of the clinical significance of total higher-order aberrations (HOA, mm), spherical aberration (Z4, 0, mm), horizontal coma (Z3, 1, mm), vertical coma (Z3, -1, mm), horizontal trefoil (Z3, 3, mm), and oblique trefoil (Z3, -3, mm)
12 months

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
yuhao shao

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
Shanghai 10th People's Hospital

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
July 1, 2021

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
September 1, 2024

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
September 1, 2024

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
March 13, 2025

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
March 20, 2025

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
March 27, 2025

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
March 27, 2025

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
March 20, 2025

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
March 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 2025AL
  • YJXYS-B-009 (Other Grant/Funding Number: Shanghai Tenth People's Hospital)
  • 202240131 (Other Grant/Funding Number: Shanghai Municipal Health Commission)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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