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

NCT06818461 | Completed

• 1 other identifier: FMBSUREC/05012025/ Saif
• Study Type: observational
• Target: 150
• Locations: 1 country
• Sites: 1

Brief Summary

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

Conditions

Myopia; Keratoconus; Refractive Surgery

Keywords

corneal biomechanics; prk; lasik; cxl

Outcome Measures

Primary Outcomes (1)

• corneal biomechanics

  6 month

Study Arms (3)

Lasik

a non-contact air puff tonometer combined with Scheimpflug imaging to assess the cornea's deformation response. Measurements will be taken at multiple postoperative time points to track biomechanical changes. Key parameters such as Deformation Amplitude (DA), Stiffness Parameter (SP-A1), Applanation Times (A1 \& A2), Peak Distance (PD), and Biomechanically Corrected IOP (bIOP) will be recorded.

Other: Corvis St Before and after lasik, PRK, CXL

PRK

a non-contact air puff tonometer combined with Scheimpflug imaging to assess the cornea's deformation response. Measurements will be taken at multiple postoperative time points to track biomechanical changes. Key parameters such as Deformation Amplitude (DA), Stiffness Parameter (SP-A1), Applanation Times (A1 \& A2), Peak Distance (PD), and Biomechanically Corrected IOP (bIOP) will be recorded.

Other: Corvis St Before and after lasik, PRK, CXL

CXL

a non-contact air puff tonometer combined with Scheimpflug imaging to assess the cornea's deformation response. Measurements will be taken at multiple postoperative time points to track biomechanical changes. Key parameters such as Deformation Amplitude (DA), Stiffness Parameter (SP-A1), Applanation Times (A1 \& A2), Peak Distance (PD), and Biomechanically Corrected IOP (bIOP) will be recorded.

Other: Corvis St Before and after lasik, PRK, CXL

Interventions

Corvis St Before and after lasik, PRK, CXL OTHER

corneal biomechanics measurment using corvis St

CXL; Lasik; PRK

Eligibility Criteria

• Age: 18 Years - 60 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)
• Sampling Method: Probability Sample

Study Population

patients coming for refractive surgery

You may qualify if:

• \- 1. Adults aged 18-60 years. 2. Patients who have undergone LASIK, PRK, or CXL at least 1 month prior to measure-ment.
• \. Stable refraction for at least 3 months post-procedure. 4. No evidence of active ocular disease or infection.

You may not qualify if:

• \. History of other ocular surgeries (excluding LASIK, PRK, or CXL). 2. Presence of keratoconus or other corneal ectatic disorders not treated with CXL.
• \. Systemic or ocular conditions affecting corneal biomechanical properties (e.g., dia-betes, connective tissue disorders).
• \. Current or recent use of medications influencing corneal biomechanics.

Sponsors & Collaborators

• Beni-Suef University: lead

Study Sites (1)

Clearvision

Mohandessin, Giza Governorate, 11344, Egypt

Location

Related Publications (1)

• Luce DA. Determining in vivo biomechanical properties of the cornea with an ocular response analyzer. J Cataract Refract Surg. 2005 Jan;31(1):156-62. doi: 10.1016/j.jcrs.2004.10.044.

  PMID: 15721708 BACKGROUND

MeSH Terms

Conditions

Myopia; Keratoconus

Condition Hierarchy (Ancestors)

Refractive Errors; Eye Diseases; Corneal Diseases

Study Design

• Study Type: observational
• Observational Model: CASE CONTROL
• Time Perspective: PROSPECTIVE
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Professour of Ophthalmology

Study Record Dates

• First Submitted: February 5, 2025
• First Posted: February 10, 2025
• Study Start: September 1, 2023
• Primary Completion: May 28, 2025
• Study Completion: October 31, 2025
• Last Updated: November 19, 2025

Record last verified: 2025-06

Locations

EG (1)