A Comparative Study Between Laser and Manual Removal of Corneal Epithelium for Photorefractive Keratectomy

Inclusion Criteria: * • Age : older than 18 years old . * Gender: Include both males and females. * Stable refraction for at least 12 months . * Intraocular pressure less than 21mmHg. * A period without wearing contact lenses (more than 4 days for soft , more than 2 weeks for rigid contact lenses ) * No history of any Autoimmune disease . * The refractive error must be one that can be treated by PRK Exclusion Criteria: * \_ patients with any eye disease (significant cataract or unstable glaucoma ) * uncontrolled external disease such as blepharitis, dry eye syndrome, and atopy/allergy. * patients with Keratoconus and other abnormalities of the cornea such as corneal ectasias , thinning , edema , interstitial or neurotrophic keratitis and extensive vascularisation . * Patients with active systemic connective tissue disease such as systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) * Ineligibility for Surgery: Exclude patients who are not suitable candidates for surgery . * Consider excluding pregnant or lactating women . * Patients unwilling to participate in the study .