Preparation of donor corneal lamellae with the use of femtosecond laser

• Grant number: 11/14699-0
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: December 01, 2011
• End date: November 30, 2013
• Field of knowledge: Engineering - Biomedical Engineering - Medical Engineering
• Principal Investigator: Milton Ruiz Alves
• Grantee: Gustavo Victor de Paula Baptista
• Host Institution: Faculdade de Medicina (FM). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

BACKGROUND: Corneal transplants (CT)can be divided into penetrating keratoplasty (PKT), where a full thickness part of the cornea is changed for another, and lamellar, where a corneal lamella (thickness less than the total) is changed. This type is subdivided into lamellar transplantation (LT) above (superficial or deep, preserving the endothelium) and endothelial or posterior LT. The major advantages of the deep LT on the PKT are the absence of endothelial rejection, and preservation of endothelial cell count of the donor, as well as lower losses of these cells in the long term. The rejection of the endothelium and endothelial failure are the main causes of failure of CT in the long term. Endothelial transplantation has complication, clarity of the graft, visual acuity and loss of endothelial cells rates similar to the PKT. He was superior to PKT in terms of early visual recovery, refractive stability, post-operative refractive results, complications and healing related to suture, and per operative and late supracoroidea bleeding risk. The postoperative quality of visual acuity (VA) is directly influenced by three factors related to surgical technique: 1) In the deep LT, visual acuity is better the less corneal stroma remain. 2) In endothelial transplantation, the thinner the flap with the donor endothelium, the better the postoperative visual acuity (VA). 3) The cutting quality (precision, accuracy and regularity) in donors and host corneas directly influence a patient's best VA. A step forward in quality of cut corneal lamellae was provided by the femtosecond laser (LF). The main advantages of using the LF in CT are: 1) Higher cutting quality (precision, accuracy and regularity), especially in deep cuts, where MKs are less reproducible and have a poorer quality of cut, allowing for better visual acuity, 2) Minor influence of the surgeon, providing less risk of damage to the lamella and endothelium, 3) Faster visual recovery, 4) Improved accuracy in obtaining appropriate sizes of lamellae, 5) Possibility of making special cuts on the edges of the lamellae, allowing a better fit between donors and hosts lamellae, 6) Ability to create two donor lamellae, one anterior and other endothelial, with higher quality of cut from a donor cornea. 7) Now it is the way to obtain corneal lamellae with the best cut quality possible. The disadvantages are the high cost and the learning curve. In 2007, the American Eye Bank SightLife introduced the process of preparation of donor corneal tissue for all types of transplants using the LF, currently providing more than 4,000 corneas for 28 countries. In 2008, there were some 40,000 CT in United States. Only the number of endothelial transplantation increased from 1,398 in 2005 to 14,159 in 2007. In Brazil, Eye Banks do not provide pre-cut corneas to deep and endothelial LT. PROUPOSE: To evaluate the efficacy and reproducibility of the use of LF in the preparation of donor corneal lamellae to deep and endothelial LT. METHODS: From a human donor cornea, will be obtained two donor corneal lamellae (one anterior and another endothelial) using the LF LDV. Will be used 50 corneas from Eye Bank for the study. Data obtained will be cut quality (precision, accuracy and reproducibility) in relation to the thickness and diameter of the lamellae made, as well as the facilities, events and difficulties to achieve the cuts.

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

GUSTAVO VICTOR; WALTON NOSÉ; SIDNEY JULIO DE FARIA E SOUSA; ROBERTO PINEDA; MILTON RUIZ ALVES. Laser de femtossegundo de baixa energia e alta frequência na confecção de lamelas corneanas doadoras. Rev. bras.oftalmol., v. 73, n. 2, p. 71-74, 2014-04-00. (11/14699-0)