PRoTECT: Corneal Wavefront Guided PRK + Epi-off CXL vs. PTK+Epi-off CXL in Keratoconus

NCT07372911 | Recruiting

• 1 other identifier: PRoTECT-CXL-TGPRK-MX
• Study Type: interventional
• Target: 50
• Locations: 1 country
• Sites: 1

Brief 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 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

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; NEI VFQ-25; Visual acuity (logMAR); Randomized clinical trial; Parallel assignment

Outcome Measures

Primary Outcomes (1)

• 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.

  Baseline to 12 months

Secondary Outcomes (10)

• Change in Kmax (Diopters)

  Baseline; 3; 6; 12 months

• Change in corneal higher-order aberrations (µm RMS)

  Baseline; 3,6,12 months

• Change in manifest refraction spherical equivalent (Diopters)

  Baseline; 3;6;12 months

• Corneal haze (Scheimpflug densitometry units)

  Baseline; 3;6;12 months

• Corvis ST metric: Ambrosio Relational Thickness horizontal (ART-h)

  Baseline; 3,6; 12 months

Study Arms (2)

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 \[equivalent to 3 minutes "on" time\].

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 \[equivalent to 3 minutes "on" time\].

Device: Schwind AMARIS excimer laser; Procedure: Corneal collagen crosslinking epi-off accelerated

Interventions

Schwind AMARIS excimer laser DEVICE

Used for corneal wavefront guided PRK therapeutic ablation (50 µm) or for PTK epithelial removal, according to arm assignment.

Corneal Wavefront Guided PRK + CXL; PTK + CXL

Corneal collagen crosslinking epi-off accelerated PROCEDURE

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 \[equivalent to 3 minutes "on" time\].

Corneal Wavefront Guided PRK + CXL; PTK + CXL

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• 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:
• y: keratoconus stage I-III (progression not mandatory)
• 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
• y: clear, unequivocal recent progression (meet ≥ 2 Table-1 criteria); late-onset documented progression may be considered

You may not qualify if:

• 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

Sponsors & Collaborators

• Instituto de Oftalmología Fundación Conde de Valenciana: lead

Study Sites (1)

Instituto de Oftalmología FAP Conde de Valenciana, IAP Sede Centro

Mexico City, Mexico City, 06800, Mexico

RECRUITING

MeSH Terms

Conditions

Keratoconus; Corneal Opacity

Condition Hierarchy (Ancestors)

Corneal Diseases; Eye Diseases

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: PARTICIPANT, OUTCOMES ASSESSOR
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: November 16, 2025
• First Posted: January 28, 2026
• Study Start: September 1, 2025
• Primary Completion (Estimated): September 1, 2026
• Study Completion (Estimated): December 30, 2027
• Last Updated: January 28, 2026

Record last verified: 2025-11

Locations

ME (1)