To evaluate the changes that occur in the intraocular pressure after corneal refractive surgery either PRK , LASIK and femtosecond laser by using Corvis CT results and applanation tonometer

This study will be prospective study. 50 Patients who will undergo refractive surgery referred from the out-patient clinic of Tanta University hospital between December 2025 and December 2026 will be included in the study . The patient will be randomly selected to do either LASIK, PRK or femtosecond laser LASIK

Patients who will undergo refractive surgery either PRK, LASIK or femtosecond laser with age between 19 and 35 years old , Myopia range from (-2.00 to -6.00 Diopter) and to maintain stability of the data we will use only the right eye of each patient will be included on the study

Kertoconus, Corneal scarring, Previous corneal infections, Minimum corneal thickness at the thinnest location less than 400 µm, History of uveitis or ocular allergy and Pre-existing glaucoma will be excluded from the study.

Age, sex, uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest and cycloplegic refraction, Slit lamp biomicroscopy, fundus examination , Central corneal thickness (CCT) and average Keratometer (K) data will be collected

Intraocular pressure will be measured by by two methods : Corvis CT and applanation tonometer for each patient and will be recorded, all the data will be collected before the refractive surgery and one month after refractive surgery

Inclusion Criteria:

• Age between 19 and 35 years old
• Myopia range from (-2.00 to -6.00 Diopter) .

Exclusion Criteria:

• Kertoconus.
• Corneal scarring.
• Previous corneal infections.
• Minimum corneal thickness at the thinnest location less than 400 µm.
• History of uveitis or ocular allergy.
• Pre-existing glaucoma.

Results after statistical analysis will be shared in the manuscript