An ophthalmological device, created by Adriana Hernández López and José Jorge García Loya, of the Department of Surgery of the Faculty of Medicine (FM) of the National Autonomous University of Mexico (UNAM), will allow improving the quality control of the donated corneal tissue for transplants, by making the process more economical, quick and objective.
With the device, in process of national and international patent, it is possible to observe the corneas in all their extension and conserving the original form for its better analysis.
According to figures from the National Transplant Center, the number of recipients on the waiting list of this tissue in the first quarter of 2019 was 6,187 patients. Each year, on average, about 3,500 transplants of this type are performed; and in 2018, 4,333 were performed, but the waiting list is still long.
The device consists of a container ring that serves as support and a 45 degree prism or mirror, which allows the cornea to be seen as if it were still integrated into the eye and to evaluate it layer by layer. “The challenge is to have control not only of the surface of the tissue, but even of the meticulousness with which it was cut or extracted from the donor, to contribute to make it the best and to ensure its transplant is a success,” explained García Loya.
Before, the specialists had to check the tissue with the naked eye, observe it through a small glass container; because once the cornea is removed, there is no way to manipulate it. But the new device offers the benefit of doing a control that was not possible before, allowing seeing in physical form small details that are crucial for the patient to recover the vision.
Adriana Hernández explained that the cornea is checked under a slit lamp with 40 increases, because the attachment (which also has a frame and a coupling channel) makes it possible. “It allows us to handle the tissue without contaminating it.”
The cornea is deposited at the bottom of the container. From there, its image is projected (with the help of the prism) towards the slit lamp, where the details can be seen. This simple principle makes possible the revision as if the tissue was still part of a body.
The expert said that the tissue should be procured in accordance with a protocol for selecting the potential donor. In addition to knowing who the donor was and his medical history, and what was the cause of death, it should be consider how the tissue was placed in the preservation medium and the temperature at which it is maintained, among other aspects.
With the use of the new device it is possible to determine the macroscopic characteristics of the tissue, to ensure that the cornea serves to be transplanted.
Most transplants are successful; however, a patient may have risk factors such as heart disease, immunosuppression or hypertension, which must be considered for the procedure to be successful. In addition, the processes of procuring the tissue should be reviewed and quality should be monitored, Hernández explained.
Source: La Jornada