Viability Of Epithelial Cells And Cleavage Of Corneal Basement After Alcohol Exposure During Laser-assisted Subepithelial Keratectomy Flap Preparation

Backround:Ethanol is used in refractive surgery to assist in the removal of epithelium before photorefractive keratectomy (PRK) and laser-assisted subepithelial keratectomy (LASEK). This method has recently been shown to enhance corneal flap lifting without significant loss of flap viability. The cleavage plane of the alcohol-induced epithelial flap is possibly located between the lamina lucida and lamina densa of the basement membrane. It is very important to retain the basement membrane, which is a very critical tissue to maintain the viability of epithelial cells. Despite of increasing number of patients having LASEK worldwide, the mechanism of action of the brief ethanol exposure during creation of the anatomic cleavage on the epithelial basement membrane and epithelial cells is unknown. Determining this mechanism becomes more and more important, and it is very instructive to clinical operation.Objective:In this study the viability of epithelial cells after various exposure times to 20% ethanol and epithelial flap preparation in laser-assisted subepithelial keratectomy (LASEK) in cadaver eyes by the PCNA staining was investigated. The anatomic cleavage on the epithelial basement membrane was determined by immunohistological and immunoflurescence staining test.Methods:6 human cadaver eyes were exposed to 20% ethanol for 20,30,40 seconds respectively,1 eye was used for control. PCNA staining test was performed to determine the viability of epithelial cells. Immunofluorescence staining using monoclonal antibodies against collagen VII, immunohistological staining using monoclonal antibodies...