CorVision® 4-year Follow-up (CorVision4yFU)

May 28, 2026 updated by: Katerina Klimesova, Gemini Eye Clinic

Four Years Extended Follow-Up on CorVision® Bioengineered Corneal Microlens: Safety and Efficacy

The objective of the study is to assess the long-term safety and effectiveness of the CorVision® microlens implanted in presbyopic patients for the management of management of presbyopia and near vision impairment. Approximately 100 patients in the Czech Republic will participate in this study. The study was reviewed and approved by an independent research ethics committee and also by the State Institute for Drug Control (SÚKL). The study will consist of a single visit during which standard, non-invasive, and painless examinations will be performed. This visit will correspond to the 4-year follow-up visit of the original clinical trial.

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.

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.
95

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

  • Czechia
      • Zlín, Czechia, 760 01
        • Gemini Eye Clinic

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

  • Child
  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Sampling Method

Non-Probability Sample

Study Population

The target population are patients who suffered from presbyopia and underwent the original CorVision clinical study are medically suitable to undertake the current clinical study investigation.

Description

Inclusion Criteria:

  • Subjects must have undergone implantation of CorVision microlens under study protocol CMG-PRT-002.
  • Provide informed consent
  • Willing to participate in the ophthalmological examinations

Exclusion Criteria:

  • Patients with severe ocular or general disorders that would prevent them from completed the visit.
  • Patients not being able to understand and give informed consent.

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.
Post-presbyopia correction with unilaterally implanted microlens
Presbyopic patients who have undergone implantation of the CorVision microlens according to study protocol CMG-PRT-002.

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
Uncorrected Near Visual Acuity of 0.3 logMAR or better
Time Frame: At least 4 years after the implantation
More than 65% of the eyes should have an Uncorrected Near Visual Acuity (UNVA) of 0.3 logMAR or better at 4 years postoperatively.
At least 4 years after the implantation
Implant removal
Time Frame: At least 4 years after the implantation
The incidence of implant rejection leading to implant removal should occur in no more than 3% of implanted eyes.
At least 4 years after the implantation

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
Clinically significant corneal haze occurrence
Time Frame: At least 4 years after the implantation
Clinically significant corneal haze is defined as any new stromal clouding in or near the laser-created pocket that leads to a reduction in central corneal clarity/transparency, is visible upon slit-lamp examination, and is graded as ≥ 2 on a standardized corneal haze grading scale.
At least 4 years after the implantation

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
Monocular Uncorrected Near Visual Acuity at Best Reading Distance
Time Frame: At least 4 years after the implantation
Change in monocular uncorrected near visual acuity and best reading distance over time
At least 4 years after the implantation
Monocular and Binocular Uncorrected Near Visual Acuity at 40 cm
Time Frame: At least 4 years after the implantation
Change in monocular and binocular Uncorrected Near Visual Acuity (UNVA) at 40 cm.
At least 4 years after the implantation
Monocular and Binocular Distance Corrected Near Visual Acuity
Time Frame: At least 4 years after the implantation
Change in monocular and binocular Distance Corrected Near Visual Acuity (DCNVA).
At least 4 years after the implantation
Monocular and Binocular Corrected Near Visual Acuity
Time Frame: At least 4 years after the implantation
Change in monocular and binocular Corrected Near Visual Acuity (CNVA) over time.
At least 4 years after the implantation
Monocular and Binocular Uncorrected Intermediate Visual Acuity (UIVA)
Time Frame: At least 4 years after the implantation
Change in monocular and binocular Uncorrected Intermediate Visual Acuity (UIVA) over time.
At least 4 years after the implantation
Monocular and Binocular Distance Corrected Intermediate Visual Acuity
Time Frame: At least 4 years after the implantation
Change in monocular and binocular Distance Corrected Intermediate Visual Acuity (DCIVA) over time.
At least 4 years after the implantation
Monocular and Binocular Uncorrected Distance Visual Acuity (UDVA)
Time Frame: At least 4 years after the implantation
Change in monocular Uncorrected Distance Visual Acuity (UDVA) over time.
At least 4 years after the implantation
Monocular and Binocular Corrected Distance Visual Acuity (CDVA)
Time Frame: At least 4 years after the implantation
Change in monocular and binocular Corrected Distance Visual Acuity (CDVA) over time.
At least 4 years after the implantation
Objective refraction
Time Frame: At least 4 years after the implantation
Change in objective refractive sphere and cylinder magnitude measured by autorefractometry.
At least 4 years after the implantation
Subjective refraction
Time Frame: At least 4 years after the implantation
Change in manifest refractive sphere and cylinder magnitude, measured in diopters (D).
At least 4 years after the implantation
Near addition
Time Frame: At least 4 years after the implantation
Change in near addition values over time.
At least 4 years after the implantation
Corneal Keratometry Measurements (K1, K2, and Kmean)
Time Frame: At least 4 years after the implantation

Change in corneal keratometry values, including K1, K2, and mean keratometry (Kmean), as measured by corneal topography over time.

Change in keratometry K1, K2 and Kmean measured in diopters over time.
At least 4 years after the implantation
Central Corneal Thickness (Pachymetry) Measurement
Time Frame: At least 4 years after the implantation
Change in central corneal thickness as measured by corneal pachymetry over time.
At least 4 years after the implantation
Endothelial Cell Density (Study Eye)
Time Frame: At least 4 years after the implantation
Change in endothelial cell density over time.
At least 4 years after the implantation
Intraocular Pressure (Study Eye)
Time Frame: At least 4 years after the implantation
Change in intraocular pressure over time.
At least 4 years after the implantation
Tear Film Break-Up Time (TBUT) Test
Time Frame: At least 4 years after the implantation
Change in tear film stability as measured by Tear Film Break-Up Time (TBUT) in units of seconds.
At least 4 years after the implantation
Tear Production (Schirmer Test)
Time Frame: At least 4 years after the implantation
Change in tear production as measured by the Schirmer test in units of mm.
At least 4 years after the implantation
Corneal Thickness Measurement Using Optical Coherence Tomography (OCT)
Time Frame: At least 4 years after the implantation
Change in corneal thickness measured at the corneal center in μm.
At least 4 years after the implantation
Abnormal findings at OCT
Time Frame: At least 4 years after the implantation
Incidence of abnormal findings on OCT.
At least 4 years after the implantation
Slit-lamp findings
Time Frame: At least 4 years after the implantation
Incidence of abnormal slit lamp findings (eyelid, conjunctiva, epithelium, stroma, central cornea clarity, cornea neovascularization, anterior chamber, iris, lens).
At least 4 years after the implantation
Contrast sensitivity
Time Frame: At least 4 years after the implantation
Determination of contrast sensitivity measured by CSV 1000 (Vector Vision) (changes from the pre-operative to the post-operative state and its stability over time will be investigated).
At least 4 years after the implantation
Defocus curve
Time Frame: At least 4 years after the implantation
Change in visual acuity measured at different defocus vergence levels during monocular defocus curve testing over time.
At least 4 years after the implantation
Aberrometry measurements using iTrace
Time Frame: At least 4 years after the implantation
Change in the total higher order aberrations (HOA) assessed by iTrace.
At least 4 years after the implantation
Subjective questionnaire QoV - patient satisfaction
Time Frame: At least 4 years after the implantation
Evaluation of patient satisfaction assessed on a scale
At least 4 years after the implantation
Subjective questionnaire QoV
Time Frame: At least 4 years after the implantation
Evaluation of patient satisfaction as assessed using the Quality of Vision (QoV) questionnaire scoring scale.
At least 4 years after the implantation
Adverse events incidence
Time Frame: At least 4 years after the implantation
Intraoperative and adverse events at each time point (numbers and percentages)
At least 4 years after the implantation

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.
Gemini Eye Clinic

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

Helpful Links

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.
June 27, 2025

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.
November 25, 2025

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.
November 25, 2025

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).
May 15, 2026

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.
May 28, 2026

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.
June 3, 2026

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.
June 3, 2026

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.
May 28, 2026

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.
May 1, 2026

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.
  • CMG-PRT-002-1

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

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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