Evaluation of the Change in the DA Ratio, IR and SSI as Parameters of Corneal Biomechanics Post Different LVC Procedures

Evaluation of the Change in the Deformation Amplitude Ratio, Integrated Radius and Stress Strain Index as Parameters of Corneal Biomechanics Post Different Laser Vision Correction Procedures

Status

Completed

Phases

Study type

Interventional

Source

ClinicalTrials.gov

Registry ID

NCT05377099

Enrollment

Registered

2022-05-17

Start date

2022-01-01

Completion date

2023-01-30

Last updated

2023-02-21

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Corneal Biomechanics

Keywords

CORVIS - Corneal Biomechanics

Brief summary

In the study, The Investigators will compare the participates' corneal biomechanical properties including: Deformation Amplitude ratio (Da Ratio) Integrated Radius (IR) Stress strain index (SSI) All measurements will be taken before and after 3 months of LVC.

Detailed description

Each Participant will undergo preoperative pentacam and corvis scan for his eyes and the 3 months post operative. The participants are divided into 3 groups, one who underwent LASIK, one PRK and one Femto LASIK. Collected data will before and after surgery will be compared in each arm and then the 3 arms will be compared together.

Interventions

DIAGNOSTIC_TESTCORVIS

Measurement of the DA ratio, IR and SSI before and after for patients under gone LASIK, femto LASIK and PRK using the CORVIS device.

Study design

Allocation

RANDOMIZED

Intervention model

PARALLEL

Primary purpose

TREATMENT

Masking

SINGLE (Subject)

Eligibility

Sex/Gender

ALL

Age

18 Years to 40 Years

Healthy volunteers

Yes

Inclusion criteria

* • Age range 18 - 40 years. * Normal eyes with normal tomographic indices. * Patients with maximum mean refractive spherical equivalent (MRSE) of -7.00 diopters and with maximum astigmatism of -3.00 diopters.

Exclusion criteria

* • Patients with any other coexisting corneal diseases. * Keratoconus eyes. * Eyes with previous refractive corneal surgery. * Patients with increased intraocular pressure.

Design outcomes

Primary

Measure	Time frame	Description
Evaluation of the changes in DA ratio, integrated radius and SSI before and after LVC	3-6 months post operative	Comparison between in DA ratio (DA ratio) in patients undergoing LASIK, Femto LASIK and PRK. Comparison between changes in integrated Radius (IR) in patients undergoing LASIK, Femto LASIK and PRK. Comparison between changes in Stress strain index (SSI) in patients undergoing LASIK, Femto LASIK and PRK. Each indices will be compared before and after the Laser vision correction (LVC) procedure and the indices are not to be compared to each other to have have a fixed unit measure. I reviewed your comment and I dont see any conflicts, to clarify how multiple measurements will be aggregated to arrive at one reported value again I am going to measure each index and compare it with itself' before and after 3 different LVC.

Countries

Egypt

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026