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

Instituto de Oftalmología Fundación Conde de Valenciana

Status: Enrolling

Conditions: Keratoconus

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

Study type: Interventional

Funder types: Other

Identifiers

NCT07372911

PRoTECT-CXL-TGPRK-MX

Details and patient eligibility

About

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.

Enrollment: 50 estimated patients

Sex: All

Ages: 18+ years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• 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

Exclusion criteria

• 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 design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: Double Blind

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50 participants in 2 patient groups

Corneal Wavefront Guided PRK + CXL

Experimental group

Description:

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

Treatment:

Device: Schwind AMARIS excimer laser

Procedure: Corneal collagen crosslinking epi-off accelerated

PTK + CXL

Active Comparator group

Description:

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

Treatment:

Device: Schwind AMARIS excimer laser

Procedure: Corneal collagen crosslinking epi-off accelerated