While OOKP is used more often in Europe, doctors U.S. typically choose a less tedious technique called the Boston Keratoprosthesis, which is similar to MOOKP but uses a prosthetic cornea instead of one grown from dental tissue and does not require cheek tissue to surround the implant.
The Boston technique, experts say, can save patients time and give them a more natural looking eye.
Doctors may use MOOKP for some uncommon situations -- including people with Stevens-Johnson syndrome, or who were chemical burn victims -- but not always.
"These conditions, although rare or uncommon, are still important because the patients may have little or no vision, and because there have not been very effective treatments to restore their vision," said Dr. James Chodosh, a cornea specialist at the Massachusetts Eye and Ear Infirmary.
However, Chodosh added, "The [MOOKP] procedure is unlikely to be very commonly used because of the difficulty, length, and invasiveness of the surgery and the cosmetic appearance after surgery."
Dr. Uyen Tran, associate professor of ophthalmology at the Vanderbilt Eye Institute, agrees that "these types of patients are not common" and says that "we probably see about 20 cases a year at our center."
Yet, while the number of patients for MOOKP may never reach the number of patients getting the Boston Keratoprosthesis, Perez said he hopes to perform more of these procedures for those in need.
"Absolutely there are a lot of patients like her (Thornton), and also patients with chemical burns… we also want to work with the Department of Defense to help with soldiers who are scarred," said Perez.
ABC's Courtney Hutchison contributed to this report.