 9. Has undergone refractive error surgery; For the purposes of this study, active ocular disease is defined as infection or inflammation which requires therapeutic treatment. An exception is made for lid abnormalities blepharitis, meibomian gland dysfunction, papillae, corneal and conjunctival staining and dry eye. Neovascularization and corneal scars are the result of previous hypoxia, infection or inflammation and are therefore not active. 