KeratoconusPRoTECTNCT07372911
PRoTECT: Corneal Wavefront Guided PRK + Epi-off CXL vs. PTK+Epi-off CXL in Keratoconus
A study testing Schwind AMARIS excimer laser and Corneal collagen crosslinking epi-off accelerated in people with Keratoconus, run by Instituto de Oftalmología Fundación Conde de Valenciana at 1 site in Mexico.
Trial summary
Keratoconus causes irregular astigmatism and reduced vision. Epi-off corneal crosslinking (CXL) stabilizes the cornea but often leaves higher-order aberrations uncorrected. This randomized, parallel-group trial compares corneal wavefront guided photorefractive keratectomy (corneal wavefront guided PRK, 50 µm… Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Keratoconus
- What is being tested?
- Schwind AMARIS excimer laser and Corneal collagen crosslinking epi-off accelerated
- Type of treatment
- Medical device, Surgery or procedure
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 50 participants
- Where
- 1 siteMexico
- Study dates
- 1 Sep 2025to 30 Dec 2027
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
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 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Age 18-40 years
- Diagnosis of keratoconus, ABCD Belin stage I-III at baseline
- Minimum (thinnest) corneal pachymetry ≥ 450 µm pre-op
- Written informed consent
- Age-stratified progression requirements:
- 18-25 y: keratoconus stage I-III (progression not mandatory)
- 25-35 y: documented progression (meet ≥ 2 Table-1 criteria below) or, if recent documentation is absent, high-risk features for future progression: Kmax > 53 D, strong family history, severe atopy with persistent eye rubbing, or any of the following over 12 months: ΔKmax ≥ 1.0 D, thinnest pachymetry decrease ≥ 10 µm, or increase in manifest cylinder ≥ 1.0 D
- 35-40 y: clear, unequivocal recent progression (meet ≥ 2 Table-1 criteria); late-onset documented progression may be considered
Who cannot join
- Central corneal scars or opacities
- Prior ocular surgery or trauma (exception: prior LASIK if it is the cause of post-surgical ectasia, per protocol text)
- Autoimmune disease or uncontrolled diabetes mellitus
- Pregnancy or lactation
- Contact lens wear within 2 weeks before baseline evaluation
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Mexico1 site, 1 recruiting
- Recruiting
Instituto de Oftalmología FAP Conde de Valenciana, IAP Sede Centro
Mexico City, Mexico City, 06800
José Carlos JC Guerrero Acosta, MD, 3314662291, jc.guerrero1226@gmail.com
About this study
Official title: Corneal Wavefront Guided PRK Combined With Epi-off Corneal Cross-Linking Versus Epi-off Corneal Cross-Linking With PTK Epithelial Removal in Keratoconus: A Randomized Clinical Trial
Keratoconus causes irregular astigmatism and reduced vision. Epi-off corneal crosslinking (CXL) stabilizes the cornea but often leaves higher-order aberrations uncorrected. This randomized, parallel-group trial compares corneal wavefront guided photorefractive keratectomy (corneal wavefront guided PRK, 50 µm therapeutic ablation) combined with accelerated epi-off CXL versus epi-off CXL with epithelial removal by phototherapeutic keratectomy (PTK) using a Schwind AMARIS excimer laser, in adults with keratoconus. The primary endpoint is change in best-corrected distance visual acuity (logMAR) at 12 months. Key secondary endpoints include Kmax, corneal higher-order aberrations, manifest refraction, Scheimpflug densitometry (haze) and Fantes grade, Corvis ST biomechanics, NEI VFQ-25, and endothelial cell density by non-contact specular microscopy at 1, 3, 6 and 12 months.
- Conditions
- Keratoconus
- Being tested
- Schwind AMARIS excimer laser, Corneal collagen crosslinking epi-off accelerated
- Keywords
- Keratoconus, Corneal ectasia, Corneal cross-linking, Corneal collagen crosslinking (CXL), Epi-off CXL, Riboflavin UV-A, Topography-guided PRK, TG-PRK, Phototherapeutic keratectomy (PTK), PTK epithelial removal, Schwind AMARIS excimer laser, Excimer laser, Athens Protocol (TG-PRK + CXL), Crete protocol (PTK + CXL), Pentacam Scheimpflug tomography, Kmax, Higher-order aberrations (HOAs), Corneal haze, Specular microscopy, Endothelial cell density
- Medical subject headings
- Keratoconus, Corneal Opacity
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Schwind AMARIS excimer laserDevice
Used for corneal wavefront guided PRK therapeutic ablation (50 µm) or for PTK epithelial removal, according to arm assignment.
Corneal collagen crosslinking epi-off acceleratedProcedure or surgery
Riboflavin-UVA crosslinking performed after epithelial removal (corneal wavefront guided PRK arm via PRK; comparator arm via PTK). Intensity: 30 mW/cm² (pulsed 1 s on / 1 s off; 50% duty cycle). Total energy (fluence): 5.4 J/cm². Total time (elapsed): 6 minutes [equivalent to 3 minutes "on" time].
| Study group | Role | What they receive |
|---|---|---|
| Corneal Wavefront Guided PRK + CXL | Experimental | Corneal wavefront guided therapeutic PRK (50 µm) with Schwind AMARIS, followed by accelerated epi-off CXL. Intensity: 30 mW/cm² (pulsed 1 s on / 1 s off; 50% duty cycle). Total energy (fluence): 5.4 J/cm². Total time (elapsed): 6 minutes [equivalent to 3 minutes "on" time]. Receives: Device: Schwind AMARIS excimer laser; Procedure: Corneal collagen crosslinking epi-off accelerated |
| PTK + CXL | Active comparator | Epithelial removal by PTK using Schwind AMARIS, followed by accelerated epi-off CXL. Intensity: 30 mW/cm² (pulsed 1 s on / 1 s off; 50% duty cycle). Total energy (fluence): 5.4 J/cm². Total time (elapsed): 6 minutes [equivalent to 3 minutes "on" time]. Receives: Device: Schwind AMARIS excimer laser; Procedure: Corneal collagen crosslinking epi-off accelerated |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in best-corrected distance visual acuity (logMAR)
ETDRS-based CDVA in logMAR; change from baseline at 12 months; primary analysis by ANCOVA adjusted for baseline; one study eye per participant.
Measured: Baseline to 12 months
Secondary outcomes (10)
Change in Kmax (Diopters)
Pentacam Scheimpflug tomography; maximum keratometry (D); change from baseline at each time point.
Measured: Baseline; 3; 6; 12 months
Change in corneal higher-order aberrations (µm RMS)
Wavefront/aberrometry total HOAs RMS (µm) over 6-mm pupil; change from baseline.
Measured: Baseline; 3,6,12 months
Change in manifest refraction spherical equivalent (Diopters)
Manifest refraction SE (D); change from baseline.
Measured: Baseline; 3;6;12 months
Corneal haze (Scheimpflug densitometry units)
CCT and corneal haze as measured by Pentacam Corneal Densitometry. Unit of measure: gray units.
Measured: Baseline; 3;6;12 months
Corvis ST metric: Ambrosio Relational Thickness horizontal (ART-h)
ART-h as measured by Corvis ST. Unit of measure: microns
Measured: Baseline; 3,6; 12 months
Visual Functioning Questionnaire (NEI VFQ-25)
NEI VFQ-25 composite and subscale scores computed per scoring manual; change from baseline. 0 to 100, where higher scores indicate better vision-related quality of life.
Measured: Baseline; 6;12 months
Endothelial cell density (cells/mm²; specular microscopy)
Non-contact specular microscopy; primary metric = endothelial cell density (cells/mm²); secondary metrics (if collected) = coefficient of variation and hexagonality; change from baseline; one study eye per participant.
Measured: Baseline; 1; 3; 6; 12 months
Serious corneal adverse events
Incidence of protocol-defined serious ocular AEs ( infectious keratitis, perforation, persistent epithelial defect >14 days, ≥20% endothelial cell density loss, visually significant stromal scarring requiring surgery).
Measured: Baseline to 12 months
Corneal haze (Fantes grade)
Fantes clinical haze grade (ordinal); recorded at each visit. Units: Fantes grade. Scale: 0-4 scale, higher scores = worse haze.
Measured: Baseline; 3; 6; 12 months
Corvis ST metric: Inverse Concavity Radius
Inverse Concavity Radius as measured by Corvis ST. Unit of measure: mm
Measured: Baseline; 3; 6; 12 months
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted28 Jan 2026
- Study start1 Sep 2025
- Primary completion1 Sep 2026 (estimated)
- Study completion30 Dec 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for KeratoconusStudies 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
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind
- Who is masked
- Participant, Outcomes assessor
- Enrolment
- 50 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Instituto de Oftalmología Fundación Conde de Valenciana
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07372911
- Sponsor's protocol ID
- PRoTECT-CXL-TGPRK-MX
- Acronym
- PRoTECT
- Status last verified
- Nov 2025
- First submitted
- 16 Nov 2025
- Last updated
- 28 Jan 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided
Study at a glance
From the registry record, last updated by the sponsor on 28 Jan 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Corneal Wavefront Guided PRK Combined With Epi-off Corneal Cross-Linking Versus Epi-off Corneal Cross-Linking With PTK Epithelial Removal in Keratoconus: A Randomized Clinical Trial
- ClinicalTrials.gov ID
- NCT07372911
- Acronym / sponsor ID
- PRoTECT / PRoTECT-CXL-TGPRK-MX
- Conditions
- Keratoconus
- Keywords
- Keratoconus, Corneal ectasia, Corneal cross-linking, Corneal collagen crosslinking (CXL), Epi-off CXL, Riboflavin UV-A, Topography-guided PRK, TG-PRK
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 50 participants (estimated)
- Lead sponsor
- Instituto de Oftalmología Fundación Conde de ValencianaUniversity, hospital or other
- Study start
- 1 Sep 2025 (actual)
- Primary completion
- 1 Sep 2026 (estimated)
- Study completion
- 30 Dec 2027 (estimated)
- First posted
- 28 Jan 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.
Keratoconus causes irregular astigmatism and reduced vision. Epi-off corneal crosslinking (CXL) stabilizes the cornea but often leaves higher-order aberrations uncorrected. This randomized, parallel-group trial compares corneal wavefront guided photorefractive keratectomy (corneal wavefront guided PRK, 50 µm therapeutic ablation) combined with accelerated epi-off CXL versus epi-off CXL with epithelial removal by phototherapeutic keratectomy (PTK) using a Schwind AMARIS excimer laser, in adults with keratoconus. The primary endpoint is change in best-corrected distance visual acuity (logMAR) at 12 months. Key secondary endpoints include Kmax, corneal higher-order aberrations, manifest refraction, Scheimpflug densitometry (haze) and Fantes grade, Corvis ST biomechanics, NEI VFQ-25, and endothelial cell density by non-contact specular microscopy at 1, 3, 6 and 12 months.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind (participant, outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Corneal Wavefront Guided PRK + CXL | Experimental | Device: Schwind AMARIS excimer laser, Procedure: Corneal collagen crosslinking epi-off acceleratedCorneal wavefront guided therapeutic PRK (50 µm) with Schwind AMARIS, followed by accelerated epi-off CXL. Intensity: 30 mW/cm² (pulsed 1 s on / 1 s off; 50% duty cycle). Total energy (fluence): 5.4 J/cm². Total time (elapsed): 6 minutes [equivalent to 3 minutes "on" time]. |
| PTK + CXL | Active comparator | Device: Schwind AMARIS excimer laser, Procedure: Corneal collagen crosslinking epi-off acceleratedEpithelial removal by PTK using Schwind AMARIS, followed by accelerated epi-off CXL. Intensity: 30 mW/cm² (pulsed 1 s on / 1 s off; 50% duty cycle). Total energy (fluence): 5.4 J/cm². Total time (elapsed): 6 minutes [equivalent to 3 minutes "on" time]. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (8 listed)
- Age 18-40 years
- Diagnosis of keratoconus, ABCD Belin stage I-III at baseline
- Minimum (thinnest) corneal pachymetry ≥ 450 µm pre-op
- Written informed consent
- Age-stratified progression requirements:
Key exclusion criteria (5 listed)
- Central corneal scars or opacities
- Prior ocular surgery or trauma (exception: prior LASIK if it is the cause of post-surgical ectasia, per protocol text)
- Autoimmune disease or uncontrolled diabetes mellitus
- Pregnancy or lactation
- Contact lens wear within 2 weeks before baseline evaluation
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 |
|---|---|---|
| Schwind AMARIS excimer laserUsed for corneal wavefront guided PRK therapeutic ablation (50 µm) or for PTK epithelial removal, according to arm assignment. | Device | Corneal Wavefront Guided PRK + CXL, PTK + CXL |
| Corneal collagen crosslinking epi-off acceleratedRiboflavin-UVA crosslinking performed after epithelial removal (corneal wavefront guided PRK arm via PRK; comparator arm via PTK). Intensity: 30 mW/cm² (pulsed 1 s on / 1 s off; 50% duty cycle). Total energy (fluence): 5.4 J/cm². Total time (elapsed): 6 minutes [equivalent to 3 minutes "on" time]. | Procedure or surgery | Corneal Wavefront Guided PRK + CXL, PTK + CXL |
Primary outcome
Change in best-corrected distance visual acuity (logMAR)
Time frame: Baseline to 12 months
ETDRS-based CDVA in logMAR; change from baseline at 12 months; primary analysis by ANCOVA adjusted for baseline; one study eye per participant.
10 secondary outcomes
Change in Kmax (Diopters)
Time frame: Baseline; 3; 6; 12 months
Change in corneal higher-order aberrations (µm RMS)
Time frame: Baseline; 3,6,12 months
Change in manifest refraction spherical equivalent (Diopters)
Time frame: Baseline; 3;6;12 months
Corneal haze (Scheimpflug densitometry units)
Time frame: Baseline; 3;6;12 months
Corvis ST metric: Ambrosio Relational Thickness horizontal (ART-h)
Time frame: Baseline; 3,6; 12 months
Visual Functioning Questionnaire (NEI VFQ-25)
Time frame: Baseline; 6;12 months
Endothelial cell density (cells/mm²; specular microscopy)
Time frame: Baseline; 1; 3; 6; 12 months
Serious corneal adverse events
Time frame: Baseline to 12 months
Corneal haze (Fantes grade)
Time frame: Baseline; 3; 6; 12 months
Corvis ST metric: Inverse Concavity Radius
Time frame: Baseline; 3; 6; 12 months
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 28 Jan 2026.
- Individual participant dataSharing planned: Undecided
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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.
Instituto de Oftalmología FAP Conde de Valenciana, IAP Sede Centro
Mexico City, Mexico
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Schwind AMARIS excimer laser and Corneal collagen crosslinking epi-off accelerated in people with Keratoconus, run by Instituto de Oftalmología Fundación Conde de Valenciana at 1 site in Mexico.
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 8 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: looking for participants now, as of the sponsor's last update on 28 Jan 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Mexico. 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?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Each site lists its own contact: choose the nearest one under Trial locations. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change in best-corrected distance visual acuity (logMAR) (time frame: Baseline to 12 months). 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 28 Jan 2026.