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

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.

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.

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.