Histologic and ultrastructural characterization of corneal femtosecond laser trephination.
OBJECTIVE
The purpose of this study was to evaluate the quality of femtosecond laser corneal trephination in eye bank eyes by histologic and ultrastructural investigation.


METHODS
We performed Z-shaped, tophat-shaped, and mushroom-shaped trephinations of swelled corneas from eye bank eyes using an Intralase FS60 system. The corneoscleral discs were fixed immediately after the laser procedure without removing the buttons. Thin and ultrathin tissue sections were examined by light and transmission electron microscopy.


RESULTS
Optical micrographs of the corneal tissue revealed that the femtosecond laser was efficient in producing Z-shaped, tophat-shaped, and mushroom-shaped dissections with reproducible high cut regularity. Investigations by transmission electron microscopy demonstrated that cut edges were of good quality devoid of thermal or mechanical damage of the adjacent tissues. However, cellular and collagenous nanometric debris was created by the laser. In the anterior stroma, they formed a layer of several microns in thickness residing on the terminated disrupted collagen fibers, whereas in the posterior stroma, they formed a thinner pseudomembrane running along the edges of the incision.


CONCLUSIONS
Corneal trephination performed by the femtosecond laser preserves the ultrastructure of the disrupted collagen fibers. In edematous corneas, a layer of cellular and collagenic debris thicker in the anterior stroma and thinner in the posterior stroma runs along the edges of the incision obtained at a constant laser energy density.
Nuzzo
Valeria
V
Laboratoire d'Optique Appliquée, ENSTA-Ecole Polytechnique-CNRS UMR 7639, Palaiseau cedex, France.
Aptel
Florent
F
Savoldelli
Michèle
M
Plamann
Karsten
K
Peyrot
Donald
D
Deloison
Florent
F
Donate
David
D
Legeais
Jean-Marc
JM
D003315:Cornea / Q000473:pathology* / Q000601:surgery* / Q000648:ultrastructure; D015715:Corneal Edema / Q000473:pathology / Q000601:surgery; D003319:Corneal Stroma / Q000473:pathology; D004210:Dissection / Q000379:methods*; D005125:Eye Banks; D006801:Humans; D053685:Laser Therapy / Q000009:adverse effects; D008854:Microscopy, Electron; D053758:Nanoparticles; D015203:Reproducibility of Results; D014207:Trephining / Q000379:methods* / Q000592:standards