Photorefractive Keratectomy for Severe Anisometropia and Isoametropia Associated With Amblyopia

Inclusion Criteria:. * Children aged 2 to 17 with significant anisometropia or isoametropia and amblyopia that have failed traditional treatment for at least 6 months. * Anisometropic group: * The anisometropia must be at least 3.00 diopters. * The amblyopic eye best corrected visual acuity must be at least 2 lines worse than the fellow eye in verbal children * Isoametropic group * Myopia must be at least -4.00 diopters in both eyes * Hyperopia must be at least +4.00 diopters in both eyes * Astigmatism must be at least +2.50 diopters in both eyes. Exclusion Criteria: * History of significant corneal abnormality that, in the investigator's opinion, may limit visual rehabilitation. * History of known collagen disorder * History of known corneal ectasia * History of previous herpes simplex keratitis * Corneal thickness of less than 450u