Cleavage of corneal basement membrane components by ethanol exposure in laser-assisted subepithelial keratectomy.
OBJECTIVE
To determine the anatomic cleavage plane after exposure to 20% ethanol for approximately 20 to 25 seconds to create an epithelial flap in laser-assisted subepithelial keratectomy (LASEK).


METHODS
Ocular Surface Research & Education Foundation, Miami, Florida, and Hermann Eye Center Refractive Surgery Center, Houston, Texas, USA.


METHODS
Immunofluorescence staining using monoclonal antibodies against laminin 5, collagen VII, and integrins beta(1) and beta(4) was performed to determine the anatomic location of the cleavage plane in an epithelial flap created by 20-second exposure to 20% ethanol in cadaver eyes and in epithelial flaps obtained from LASEK patients.


RESULTS
Immunofluorescence staining to laminin 5 and integrin beta(4) was patchy in the lifted flap and the remaining corneal basement membrane. Immunostaining to collagen VII, the main component of anchoring fibrils, remained exclusively in the corneal bed. Immunostaining to integrin beta(1), present in the pericellular location of all epithelial cell layers, remained exclusively in the epithelial flap. This finding was consistent in cadaver corneas and LASEK epithelial flaps.


CONCLUSIONS
The cleavage plane of the ethanol-induced corneal epithelial flap is located between the lamina lucida and the lamina densa of the basement membrane, where integrin beta(4) interacts with laminin 5 to form hemidesmosomes.
Espana
Edgar M
EM
Ocular Surface Center and Ocular Surface Research & Education Foundation, Miami, Florida 33176, USA.
Grueterich
Martin
M
Mateo
Antonio
A
Romano
Andre C
AC
Yee
Steven B
SB
Yee
Richard W
RW
Tseng
Scheffer C G
SC
D000911:Antibodies, Monoclonal; D001485:Basement Membrane / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D024143:Collagen Type VII / Q000378:metabolism; D019573:Epithelium, Corneal / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D000431:Ethanol / Q000494:pharmacology*; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D019012:Integrin beta1 / Q000378:metabolism; D039663:Integrin beta4 / Q000378:metabolism; D020731:Keratomileusis, Laser In Situ / Q000379:methods*; D007797:Laminin / Q000378:metabolism; D013524:Surgical Flaps
D000911:Antibodies, Monoclonal; D024143:Collagen Type VII; D019012:Integrin beta1; D039663:Integrin beta4; D007797:Laminin; C097043:laminin alpha5; D000431:Ethanol