Effect of different femtosecond laser-firing patterns on collagen disruption during refractive lenticule extraction.
OBJECTIVE
To evaluate the changes in corneal collagen architecture subjected to different laser-firing patterns during refractive lenticule extraction.


METHODS
Singapore Eye Research Institute, Singapore.


METHODS
Experimental study.


METHODS
Refractive lenticule extraction was performed in rabbits without lenticule removal. Rabbits were divided into 4 groups that had incisions in the following firing patterns: (A) from periphery in (lenticule's posterior surface) and from center out (lenticule's anterior surface); (B) from center out and from center out; (C) from periphery in and from periphery in; and (D) from center out and from periphery in. The corneas were collected 18 hours postoperatively and were subjected to immunofluorescent staining of fibronectin, CD11b, and collagen type I. Ultrastructural analysis was performed using transmission electron microscopy (TEM).


RESULTS
Refractive lenticule extraction-treated corneas showed no significant difference in fibronectin and CD11b expression. Similar expression patterns of collagen type I were observed in corneas that had femtosecond firing patterns A, B, and C; however, a discontinuous and relatively more intense staining pattern along the anterior plane of the lenticule was detected in corneas treated with pattern D. The TEM also showed a more disrupted collagen arrangement along the anterior incision site in pattern D-treated corneas.


CONCLUSIONS
Differential laser firing patterns during refractive lenticule extraction resulted in different levels of collagen derangement along the anterior plane of the lenticule, with pattern D showing the most disrupted surface. Such disruption in the collagen architecture might affect postoperative visual recovery and refractive outcomes.


BACKGROUND
No author has a financial or proprietary interest in any material or method mentioned.
Tissue Engineering and Stem Cell Group, Singapore Eye Research Institute, Singapore.
Andri K
AK
Riau
Romesh I
RI
Angunawela
Shyam S
SS
Chaurasia
Donald T
DT
Tan
Jodhbir S
JS
Mehta
D000818:Animals; D039481:CD11b Antigen / Q000378:metabolism; D024042:Collagen Type I / Q000378:metabolism*; D003319:Corneal Stroma / Q000378:metabolism* / Q000601:surgery* / Q000648:ultrastructure; D048988:Corneal Surgery, Laser / Q000379:methods*; D005353:Fibronectins / Q000378:metabolism; D019084:Fluorescent Antibody Technique, Indirect; D054018:Lasers, Excimer; D018613:Microscopy, Confocal; D046529:Microscopy, Electron, Transmission; D011817:Rabbits; D013524:Surgical Flaps; D016707:Tissue Fixation
D039481:CD11b Antigen; D024042:Collagen Type I; D005353:Fibronectins