Keratoconus; Post-Refractive EctasiaNCT07905079
Retrospective Study of Corneal Tissue Addition Keratoplasty for Keratoconus and Post-Refractive Ectasia
An observational study of Keratoconus; Post-Refractive Ectasia, run by Corneagen LLC at 5 sites in United States.
Trial summary
This retrospective, multi-center observational study evaluates clinical outcomes in patients with keratoconus or post-refractive ectasia who previously underwent Corneal Tissue Addition Keratoplasty (CTAK) as part of routine clinical care. Read more about this study
- Who is it for?
- Any age
- Conditions the study is for
- Keratoconus; Post-Refractive Ectasia
- What is being tested?
- Corneal Tissue Addition Keratoplasty (CTAK)
- Type of treatment
- Surgery or procedure
- How many people
- 61 participants
- Where
- 5 sitesUnited States
- Study dates
- 8 Jun 2026to 30 Sep 2026
- 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 Any age
- All sexes
- No healthy volunteers
- Child, Adult, Older adult
Study population: Patients with keratoconus or post-refractive ectasia who previously underwent CTAK as part of routine clinical care at participating clinical sites and have the required clinical records.
Who may be able to join
- Diagnosis of keratoconus or post-refractive ectasia.
- Underwent Corneal Tissue Addition Keratoplasty (CTAK) in one or both eyes.
- Availability of baseline clinical data.
- At least six months of postoperative follow-up, with the required six-month clinical data documented in the medical record on or before the study data cutoff date.
Who cannot join
- Missing baseline or follow-up data, or otherwise insufficient clinical data for analysis.
- Prior corneal procedures that significantly confound clinical outcomes. Prior LASIK, PRK, and corneal cross-linking are permitted.
- Cataract surgery or LASIK/PRK performed concurrently with CTAK or before the six-month postoperative visit.
- History of cataract surgery in the study eye, whether before or after CTAK.
- CTAK performed as part of a previous clinical trial.
Trial locations and contacts
5 sites in 1 country.
5 sites in 1 country
United States5 sites
Eye Associates of New Mexico, Ltd.
Albuquerque, New Mexico, 87113
Cleveland Eye Clinic
Brecksville, Ohio, 44141
Buena Vista Eye Care, PLLC
El Paso, Texas, 79902
Eye Specialists & Surgeons of Northern Virginia
Fairfax, Virginia, 22033
Cape Fear Eye Associates
Fayetteville, North Carolina, 28304
About this study
Official title: Retrospective Multi-Center Clinical Outcomes Study Evaluating the Safety and Effectiveness of Corneal Tissue Addition Keratoplasty (CTAK) in Patients With Keratoconus or Post-Refractive Ectasia
This retrospective, multi-center observational study evaluates clinical outcomes in patients with keratoconus or post-refractive ectasia who previously underwent Corneal Tissue Addition Keratoplasty (CTAK) as part of routine clinical care.
The primary objective is to evaluate changes in corneal curvature, measured by steep keratometry (K2), maximum keratometry (Kmax), and mean keratometry (Kmean), from preoperative baseline to six months following CTAK.
Read more
Secondary outcomes include changes in uncorrected and corrected distance visual acuity, refractive stability, documented postoperative complications, subsequent corneal transplantation, and exploratory analyses across payer categories.
The study uses existing medical records from up to eight participating clinical sites, targeting up to 100 treated eyes. No study-specific intervention, patient contact, or prospective clinical assessments will occur.
Read the detailed description
Corneal Tissue Addition Keratoplasty (CTAK) is a surgical procedure involving implantation of a customized, gamma-irradiated donor corneal tissue segment into a femtosecond laser-created intrastromal channel. The procedure is designed to reshape the cornea and improve visual function in patients with keratoconus or post-refractive ectasia.
This retrospective, multi-center observational chart review evaluates clinical outcomes in patients who previously underwent CTAK as part of routine clinical care. The study will review existing medical records from up to eight participating clinical sites, targeting up to 100 treated eyes.
The primary objective is to evaluate changes in corneal curvature, measured by steep keratometry (K2), maximum keratometry (Kmax), and mean keratometry (Kmean), from preoperative baseline to six months following CTAK.
Secondary outcomes include changes in uncorrected distance visual acuity (UDVA) and corrected distance visual acuity (CDVA), refractive stability over time, documented postoperative complications and adverse events, and progression to corneal transplantation. Exploratory analyses will evaluate outcomes across payer categories and clinical settings.
Clinical data will be obtained from existing medical records, including corneal tomography and keratometry, visual acuity measurements where available, relevant prior ocular procedures, and documented postoperative outcomes. The primary assessment occurs at six months, with additional available observations at one, three, and twelve months.
The primary unit of analysis is the treated eye. Statistical methods will account for correlation between eyes when both eyes of an individual patient are included.
No study-specific intervention, patient contact, additional clinical visits, or prospective clinical assessments will occur. Clinical care was provided independently of this retrospective study.
The study received a Category 4 exemption determination from Sterling IRB on June 8, 2026, along with approval of a waiver of HIPAA authorization.
- Conditions
- Keratoconus; Post-Refractive Ectasia
- Being tested
- Corneal Tissue Addition Keratoplasty (CTAK)
- Keywords
- Corneal Tissue Addition Keratoplasty, CTAK, Keratoconus, Post-Refractive Ectasia, Corneal Ectasia, Intrastromal Corneal Inlay, Donor Corneal Tissue, Corneal Curvature, Keratometry, Kmax, Kmean, Steep Keratometry, Retrospective Study, Anterior Lamellar Keratoplasty, ALK
- Medical subject headings
- Keratoconus
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Corneal Tissue Addition Keratoplasty (CTAK)Procedure or surgery
Also called CTAK
Corneal Tissue Addition Keratoplasty (CTAK) involves implantation of a customized, gamma-irradiated donor corneal tissue segment into a femtosecond laser-created intrastromal channel. All procedures were performed as part of routine clinical care before and independently of this retrospective study. No interventions are assigned or administered as part of the study.
| Study group | Role | What they receive |
|---|---|---|
| Patients Treated With CTAK | Retrospective, multi-center observational cohort study using existing medical records of patients who previously underwent Corneal Tissue Addition Keratoplasty (CTAK) for keratoconus or post-refractive ectasia. Clinical outcomes are evaluated at baseline and available postoperative follow-up intervals, with a primary assessment at six months. No study-specific interventions or patient contact occur. Receives: Procedure: Corneal Tissue Addition Keratoplasty (CTAK) |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in K2 (Steep Keratometry)
Change in steep corneal keratometry, measured in diopters, from preoperative baseline to six months after CTAK.
Measured: Baseline to 6 months
Change in Maximum Keratometry (Kmax) from preoperative baseline to six months after CTAK
Maximum corneal keratometry is measured in diopters using corneal tomography.
Measured: Baseline to 6 months
Change in Mean Keratometry (Kmean) from preoperative baseline to six months after CTAK
Mean corneal keratometry is measured in diopters using corneal tomography.
Measured: Baseline to 6 months
Secondary outcomes (6)
Change in Uncorrected Distance Visual Acuity (UDVA) from baseline to 6 months
Measured using the site's Standard of Care practice for collecting visual acuity and recorded in Snellen notation.
Measured: Baseline to 6 months
Change in Corrected Distance Visual Acuity (CDVA) from baseline to 6 months
Measured using the site's Standard of Care practice for collecting visual acuity and recorded in Snellen notation.
Measured: Baseline to 6 months
Refractive Stability
Change in post-operative MRSE and astigmatism from baseline to 6-months, when available.
Measured: Baseline through available follow-up
Number of Participants with CTAK-Related Adverse Events and Complications as Assessed by Protocol v2.0
Incidence of documented clinically significant procedure-related complications and secondary surgical interventions.
Measured: From CTAK surgery through 6-months post-op
Progression to Corneal Transplantation
Number and Proportion of Study Eyes that Progressed to Undergoing a Corneal Transplant following CTAK.
Measured: From CTAK surgery through 6-months post-op
Comparison of Change in Keratometry Measurements from Baseline to 6-months by Primary Payer Category
Exploratory comparison of changes in Maximum Keratometry (Kmax), Mean Keratometry (Kmean), and Steep Keratometry (K2) from baseline to the 6-month postoperative visit across payer categories.
Measured: Baseline to 6 months
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted29 Oct 2026
- Study start8 Jun 2026
- Primary completion30 Sep 2026
- Study completion30 Sep 2026
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Keratoconus; Post-Refractive EctasiaStudies 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
- Cohort
- Time perspective
- Retrospective
- Enrolment
- 61 participants (actual)
Sponsor and investigators
- Lead sponsor
- Corneagen LLC
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Mitch O'Donnell, Study director, Corneagen LLC
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07905079
- Sponsor's protocol ID
- CTAK-Retro-001
- Status last verified
- Oct 2026
- First submitted
- 23 Oct 2026
- Last updated
- 29 Oct 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: Individual participant data will not be made publicly available due to patient privacy and confidentiality considerations associated with retrospective medical record data. Aggregate study findings are expected to be published in a peer-reviewed journal.
Study at a glance
From the registry record, last updated by the sponsor on 29 Oct 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Retrospective Multi-Center Clinical Outcomes Study Evaluating the Safety and Effectiveness of Corneal Tissue Addition Keratoplasty (CTAK) in Patients With Keratoconus or Post-Refractive Ectasia
- ClinicalTrials.gov ID
- NCT07905079
- Acronym / sponsor ID
- CTAK-Retro-001
- Conditions
- Keratoconus; Post-Refractive Ectasia
- Keywords
- Corneal Tissue Addition Keratoplasty, CTAK, Keratoconus, Post-Refractive Ectasia, Corneal Ectasia, Intrastromal Corneal Inlay, Donor Corneal Tissue, Corneal Curvature
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 61 participants (actual)
- Lead sponsor
- Corneagen LLCUniversity, hospital or other
- Study start
- 8 Jun 2026 (actual)
- Primary completion
- 30 Sep 2026 (actual)
- Study completion
- 30 Sep 2026 (actual)
- First posted
- 29 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.
This retrospective, multi-center observational study evaluates clinical outcomes in patients with keratoconus or post-refractive ectasia who previously underwent Corneal Tissue Addition Keratoplasty (CTAK) as part of routine clinical care.
The primary objective is to evaluate changes in corneal curvature, measured by steep keratometry (K2), maximum keratometry (Kmax), and mean keratometry (Kmean), from preoperative baseline to six months following CTAK.
Secondary outcomes include changes in uncorrected and corrected distance visual acuity, refractive stability, documented postoperative complications, subsequent corneal transplantation, and exploratory analyses across payer categories.
The study uses existing medical records from up to eight participating clinical sites, targeting up to 100 treated eyes. No study-specific intervention, patient contact, or prospective clinical assessments will occur.
Detailed description
Corneal Tissue Addition Keratoplasty (CTAK) is a surgical procedure involving implantation of a customized, gamma-irradiated donor corneal tissue segment into a femtosecond laser-created intrastromal channel. The procedure is designed to reshape the cornea and improve visual function in patients with keratoconus or post-refractive ectasia.
This retrospective, multi-center observational chart review evaluates clinical outcomes in patients who previously underwent CTAK as part of routine clinical care. The study will review existing medical records from up to eight participating clinical sites, targeting up to 100 treated eyes.
The primary objective is to evaluate changes in corneal curvature, measured by steep keratometry (K2), maximum keratometry (Kmax), and mean keratometry (Kmean), from preoperative baseline to six months following CTAK.
Secondary outcomes include changes in uncorrected distance visual acuity (UDVA) and corrected distance visual acuity (CDVA), refractive stability over time, documented postoperative complications and adverse events, and progression to corneal transplantation. Exploratory analyses will evaluate outcomes across payer categories and clinical settings.
Clinical data will be obtained from existing medical records, including corneal tomography and keratometry, visual acuity measurements where available, relevant prior ocular procedures, and documented postoperative outcomes. The primary assessment occurs at six months, with additional available observations at one, three, and twelve months.
The primary unit of analysis is the treated eye. Statistical methods will account for correlation between eyes when both eyes of an individual patient are included.
No study-specific intervention, patient contact, additional clinical visits, or prospective clinical assessments will occur. Clinical care was provided independently of this retrospective study.
The study received a Category 4 exemption determination from Sterling IRB on June 8, 2026, along with approval of a waiver of HIPAA authorization.
Study design
- Observational model
- Cohort
- Time perspective
- Retrospective
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Patients Treated With CTAK | – | Procedure: Corneal Tissue Addition Keratoplasty (CTAK)Retrospective, multi-center observational cohort study using existing medical records of patients who previously underwent Corneal Tissue Addition Keratoplasty (CTAK) for keratoconus or post-refractive ectasia. Clinical outcomes are evaluated at baseline and available postoperative follow-up intervals, with a primary assessment at six months. No study-specific interventions or patient contact occur. |
Who may qualify
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Child, Adult, Older adult
- Study population
- Patients with keratoconus or post-refractive ectasia who previously underwent CTAK as part of routine clinical care at participating clinical sites and have the required clinical records.
Key inclusion criteria (4 listed)
- Diagnosis of keratoconus or post-refractive ectasia.
- Underwent Corneal Tissue Addition Keratoplasty (CTAK) in one or both eyes.
- Availability of baseline clinical data.
- At least six months of postoperative follow-up, with the required six-month clinical data documented in the medical record on or before the study data cutoff date.
Key exclusion criteria (5 listed)
- Missing baseline or follow-up data, or otherwise insufficient clinical data for analysis.
- Prior corneal procedures that significantly confound clinical outcomes. Prior LASIK, PRK, and corneal cross-linking are permitted.
- Cataract surgery or LASIK/PRK performed concurrently with CTAK or before the six-month postoperative visit.
- History of cataract surgery in the study eye, whether before or after CTAK.
- CTAK performed as part of a previous clinical trial.
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 |
|---|---|---|
| Corneal Tissue Addition Keratoplasty (CTAK)Also: CTAKCorneal Tissue Addition Keratoplasty (CTAK) involves implantation of a customized, gamma-irradiated donor corneal tissue segment into a femtosecond laser-created intrastromal channel. All procedures were performed as part of routine clinical care before and independently of this retrospective study. No interventions are assigned or administered as part of the study. | Procedure or surgery | Patients Treated With CTAK |
Primary outcome
Change in K2 (Steep Keratometry)
Time frame: Baseline to 6 months
Change in steep corneal keratometry, measured in diopters, from preoperative baseline to six months after CTAK.
Change in Maximum Keratometry (Kmax) from preoperative baseline to six months after CTAK
Time frame: Baseline to 6 months
Maximum corneal keratometry is measured in diopters using corneal tomography.
Change in Mean Keratometry (Kmean) from preoperative baseline to six months after CTAK
Time frame: Baseline to 6 months
Mean corneal keratometry is measured in diopters using corneal tomography.
6 secondary outcomes
Change in Uncorrected Distance Visual Acuity (UDVA) from baseline to 6 months
Time frame: Baseline to 6 months
Change in Corrected Distance Visual Acuity (CDVA) from baseline to 6 months
Time frame: Baseline to 6 months
Refractive Stability
Time frame: Baseline through available follow-up
Number of Participants with CTAK-Related Adverse Events and Complications as Assessed by Protocol v2.0
Time frame: From CTAK surgery through 6-months post-op
Progression to Corneal Transplantation
Time frame: From CTAK surgery through 6-months post-op
Comparison of Change in Keratometry Measurements from Baseline to 6-months by Primary Payer Category
Time frame: Baseline to 6 months
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 29 Oct 2026.
- Individual participant dataSharing planned: No. Individual participant data will not be made publicly available due to patient privacy and confidentiality considerations associated with retrospective medical record data. Aggregate study findings are expected to be published in a peer-reviewed journal.
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.
Mitch O'Donnell study director
Corneagen LLC
5 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Keratoconus; Post-Refractive Ectasia, run by Corneagen LLC at 5 sites in United States.
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 4 inclusion and 5 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 29 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 5 sites in United States. 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?
Change in K2 (Steep Keratometry) (time frame: Baseline to 6 months). 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 29 Oct 2026.