Assessment of Corneal Biomechanical Properties Using Corvis ST Following LASIK, PRK, and CXL

Active, not recruiting

• Conditions: Keratoconus; Refractive Surgery; Myopia

• Registration Number: NCT06818461
• Lead Sponsor: Beni-Suef University

Brief Summary

To evaluate corneal biomechanical changes using the Corvis ST in patients who have under-gone LASIK, PRK, and corneal cross-linking (CXL).

Detailed Description

This observational study aims to evaluate corneal biomechanical changes in patients who have undergone LASIK, PRK, and corneal cross-linking (CXL) using the Corvis ST (Oculus). A total of 90 patients will be recruited from the ClearVision Laser Center database between January 2025 and December 2025. Participants will undergo non-contact biomechanical assessments at multiple postoperative time points to track corneal stability and elasticity over time.

Data Collection \& Measurements Patient demographics, clinical history, and baseline preoperative data, including corneal thickness (pachymetry) and refractive status, will be collected. The Corvis ST will be used to measure key biomechanical parameters, such as Corneal Deformation Amplitude (CDA), Applanation Times (A1T \& A2T), Radius of Curvature at Highest Concavity (RHC), Stiffness Parameter (SP-A1), Integrated Radius (IR), and the Corvis Biomechanical Index (CBI).

Measurement Protocol

All measurements will be conducted in a controlled environment with stable room temperature and humidity. Patients will be properly aligned, and three consecutive measurements per eye will be taken to ensure repeatability. Data will be recorded at specific intervals:

LASIK \& PRK: 1 month, 3 months, 6 months, and 12 months CXL: 1 month, 3 months, 6 months, 12 months, and 24 months Potential Benefits \& Risks The study aims to provide valuable insights into corneal biomechanical stability post-surgery, improving postoperative management and long-term visual outcomes. Risks are minimal, with only transient discomfort associated with the non-invasive Corvis ST measurements.

This study will contribute to a better understanding of corneal biomechanics in refractive and therapeutic procedures, potentially guiding future surgical decisions and patient care strategies.

Study Timeline

• Study Start: 2023-09-01
• Study First Submitted: 2025-02-05
• Study First Submitted QC: 2025-02-05
• Study First Posted: 2025-02-10
• Status Verified: 2025-05
• Last Update Submitted: 2025-05-11
• Last Update Posted: 2025-05-14
• Primary Completion: 2025-05-28
• Study Completion: 2025-07-31

Recruitment & Eligibility

• Status: ACTIVE_NOT_RECRUITING
• Sex: All
• Target Recruitment: 150

Inclusion Criteria

• 1. Adults aged 18-60 years. 2. Patients who have undergone LASIK, PRK, or CXL at least 1 month prior to measure-ment.

3. Stable refraction for at least 3 months post-procedure. 4. No evidence of active ocular disease or infection.

Exclusion Criteria

• 1. History of other ocular surgeries (excluding LASIK, PRK, or CXL). 2. Presence of keratoconus or other corneal ectatic disorders not treated with CXL.

  2. Systemic or ocular conditions affecting corneal biomechanical properties (e.g., dia-betes, connective tissue disorders).

  3. Current or recent use of medications influencing corneal biomechanics.

Study & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
corneal biomechanics	6 month

Trial Locations

Locations (1)

Clearvision; 🇪🇬 Mohandessin, Giza, Egypt