CorVision® 4-year Follow-up (CorVision4yFU)

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: Completed
• Conditions: Presbyopia

• Study Type: Observational
• Enrollment (Actual): 95

Contacts and Locations

Study Locations

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

Participation Criteria

Eligibility Criteria

• 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

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort
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

Outcome Measure	Measure Description	Time Frame
Uncorrected Near Visual Acuity of 0.3 logMAR or better	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	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

Outcome Measure	Measure Description	Time Frame
Clinically significant corneal haze occurrence	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

Outcome Measure	Measure Description	Time Frame
Monocular Uncorrected Near Visual Acuity at Best Reading Distance	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	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	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	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)	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	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)	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)	Change in monocular and binocular Corrected Distance Visual Acuity (CDVA) over time.	At least 4 years after the implantation
Objective refraction	Change in objective refractive sphere and cylinder magnitude measured by autorefractometry.	At least 4 years after the implantation
Subjective refraction	Change in manifest refractive sphere and cylinder magnitude, measured in diopters (D).	At least 4 years after the implantation
Near addition	Change in near addition values over time.	At least 4 years after the implantation
Corneal Keratometry Measurements (K1, K2, and Kmean)	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	Change in central corneal thickness as measured by corneal pachymetry over time.	At least 4 years after the implantation
Endothelial Cell Density (Study Eye)	Change in endothelial cell density over time.	At least 4 years after the implantation
Intraocular Pressure (Study Eye)	Change in intraocular pressure over time.	At least 4 years after the implantation
Tear Film Break-Up Time (TBUT) Test	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)	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)	Change in corneal thickness measured at the corneal center in μm.	At least 4 years after the implantation
Abnormal findings at OCT	Incidence of abnormal findings on OCT.	At least 4 years after the implantation
Slit-lamp findings	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	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	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	Change in the total higher order aberrations (HOA) assessed by iTrace.	At least 4 years after the implantation
Subjective questionnaire QoV - patient satisfaction	Evaluation of patient satisfaction assessed on a scale	At least 4 years after the implantation
Subjective questionnaire QoV	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	Intraoperative and adverse events at each time point (numbers and percentages)	At least 4 years after the implantation

Collaborators and Investigators

• Sponsor: Gemini Eye Clinic

Publications and helpful links

Helpful Links

• the protocol of the original study - ClinicalTrials.gov ID: NCT04465409

Study record dates

Study Major Dates

• Study Start (Actual): June 27, 2025
• Primary Completion (Actual): November 25, 2025
• Study Completion (Actual): November 25, 2025

Study Registration Dates

• First Submitted: May 15, 2026
• First Submitted That Met QC Criteria: May 28, 2026
• First Posted (Actual): June 3, 2026

Study Record Updates

• Last Update Posted (Actual): June 3, 2026
• Last Update Submitted That Met QC Criteria: May 28, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Keywords: presbyopia; eye surgery; microlens; CorVision
• Additional Relevant MeSH Terms: Eye Diseases; Refractive Errors; Presbyopia
• Other Study ID 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