Corneal wavefront-guided PRK plus epi-off CXL versus PTK plus epi-off CXL for keratoconus
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
This trial tests whether adding corneal wavefront-guided PRK to epi-off corneal cross-linking gives better vision than PTK plus epi-off CXL in adults with keratoconus.
Quick facts
| Phase | Not applicable |
|---|---|
| Study type | Interventional |
| Enrollment | 50 (estimated) |
| Ages | 18 Years and up |
| Sex | All |
| Sponsor | Instituto de Oftalmología Fundación Conde de Valenciana Academic / other |
| Locations | 1 site (Mexico City, Mexico City) |
| Trial ID | NCT07372911 on ClinicalTrials.gov |
What this trial studies
This is a randomized, parallel-group trial comparing two surface-ablation approaches combined with accelerated epi-off corneal collagen cross-linking using a Schwind AMARIS excimer laser. One arm receives corneal wavefront-guided PRK (50 µm therapeutic ablation) followed by accelerated epi-off CXL, and the other arm receives epithelial removal by PTK followed by the same accelerated epi-off CXL protocol. The primary outcome is change in best-corrected distance visual acuity (logMAR) at 12 months, with key secondary outcomes including Kmax, corneal higher-order aberrations, manifest refraction, densitometry/haze, corneal biomechanics, NEI VFQ-25, and endothelial cell density measured at 1, 3, 6 and 12 months. Eligible participants are adults 18–40 years with ABCD Belin stage I–III keratoconus and minimum thinnest pachymetry ≥ 450 µm, with age-stratified progression requirements.
Who should consider this trial
Good fit: Adults 18–40 years old with ABCD Belin stage I–III keratoconus, thinnest corneal pachymetry ≥ 450 µm, and meeting the trial's age-stratified progression or high-risk criteria are the intended participants.
Not a fit: Patients with advanced disease beyond stage III, central corneal scars or opacities, thinnest pachymetry under 450 µm, autoimmune disease, prior incompatible ocular surgery, or those outside the 18–40 age range are unlikely to benefit or be eligible.
Why it matters
Potential benefit: If successful, the combined wavefront-guided PRK plus CXL approach could improve best-corrected visual acuity and reduce irregular higher-order aberrations, leading to better visual quality for patients with keratoconus.
How similar studies have performed: Prior reports combining surface ablation (topography- or PRK-guided) with CXL have shown improvements in vision and reduced irregular astigmatism, but head-to-head comparisons of wavefront-guided PRK versus PTK in this setting are limited.
Eligibility criteria
Show full inclusion / exclusion criteria
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
Where this trial is running
Mexico City, Mexico City
- Instituto de Oftalmología FAP Conde de Valenciana, IAP Sede Centro — Mexico City, Mexico City, Mexico (Recruiting)
How to participate
- Review the eligibility criteria above with your treating physician.
- Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
- Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.