A system for treating eyes, comprising: a mask device configured to be positioned over first and second eyes (1a, 1b) of a face, the mask device including an anterior side and a posterior side, the posterior side configured to be positioned proximate to the face and the anterior side configured to be positioned distally from the face, the mask device including an outer wall extending at least between the anterior side and the posterior side, the outer wall defining a chamber extending across the first and second eyes, the chamber including a first section and a second section, the first section configured to be positioned over the first eye, the second section configured to be positioned over the second eye, the anterior side including a first transmission region disposed over the first section and a second transmission region disposed over the second section, the first transmission region allowing a first photoactivating light for the first eye to be delivered into the first section, the second transmission region allowing a second photoactivating light for the second eye to be delivered into the second section; at least one oxygen source storing oxygen; a gas delivery system coupling the at least one oxygen source to the mask device; a controller including a processor configured to determine treatment parameters relating to delivery of oxygen into the chamber of the mask device to achieve desired biomechanical changes, wherein the gas delivery system delivers the oxygen from the at least one oxygen source into the chamber of the mask device according to the treatment parameters; at least one illumination device configured to deliver at least one of the first photoactivating light or the second photoactivating light; and a first solution applicator coupled to the mask device and configured to deliver a first solution to the first eye, and a second solution applicator coupled to the mask device and configured to deliver a second solution to the second eye. a mask device configured to be positioned over first and second eyes (1a, 1b) of a face, the mask device including an anterior side and a posterior side, the posterior side configured to be positioned proximate to the face and the anterior side configured to be positioned distally from the face, the mask device including an outer wall extending at least between the anterior side and the posterior side, the outer wall defining a chamber extending across the first and second eyes, the chamber including a first section and a second section, the first section configured to be positioned over the first eye, the second section configured to be positioned over the second eye, the anterior side including a first transmission region disposed over the first section and a second transmission region disposed over the second section, the first transmission region allowing a first photoactivating light for the first eye to be delivered into the first section, the second transmission region allowing a second photoactivating light for the second eye to be delivered into the second section; at least one oxygen source storing oxygen; a gas delivery system coupling the at least one oxygen source to the mask device; a controller including a processor configured to determine treatment parameters relating to delivery of oxygen into the chamber of the mask device to achieve desired biomechanical changes, wherein the gas delivery system delivers the oxygen from the at least one oxygen source into the chamber of the mask device according to the treatment parameters; at least one illumination device configured to deliver at least one of the first photoactivating light or the second photoactivating light; and a first solution applicator coupled to the mask device and configured to deliver a first solution to the first eye, and a second solution applicator coupled to the mask device and configured to deliver a second solution to the second eye.