Topography-Guided Customized PRK Versus Q-value Adjusted PRK in Correction of Myopia With or Without Astigmatism

Topography-Guided Customized PRK (Photorefractive Keratectomy) Versus Q-value Adjusted PRK in Correction of Myopia With or Without Astigmatism

This study will include patients who will undergo PRK in both eyes, for each patient each eye will be randomly allocated to one of 2 procedures:

topography-guided ablation in one eye (group I) and Q-factor customized ablation in the other eye (group II).

Alcon/Wavelight Light Laser Technolo¬gie (GmbH, Erlangen, Germany) will be used for photoablation.

The wavelight Topolyzer (Wavelight AG, Erlan¬gen, Germany)and CSO Sirius scheimpflug camera combined with Placido corneal topography (CSO, Florence,Italy) will be used before and 1, 3 and 6 months after PRK. Refrac¬tive visual outcomes and corneal aberration changes will be compared between the two treatment modalities.

Inclusion Criteria:

• Age more than 18 years
• Myopia with up to -6.5 D with or without astigmatism up to -4.75 D

Exclusion Criteria:

• anterior segment abnormalities (ie, cataracts, corneal scarring)
• basement membrane disease
• history of recurrent corneal erosions
• Schirmer's test less than 5 mm
• established or forme fruste keratoconus
• macular or retinal disease
• current use of immunosuppressive therapy
• autoimmune disease
• pregnancy, and lactation