| 摘要 |
A method for improving integrity and accuracy of removal or hinged removal of elevated tissue layers particularly of a cornea. The area of tissue removal is isolated from remaining tissue by a shallow complete perimeter cut, substantially normal to the tissue surface. With a cornea, a perimeter in the form of a circumference is shallowly scored into the cornea tissue for a depth somewhat greater than that of the tissue to be removed (and of an appropriate diameter) by means of a surgical trephine. Corneal tissue, normally under tension tends to separate at the score site to form a groove with the circumscribed area becoming additionally slightly elevated from the adjacent corneal tissue because of release of tension across the groove site. Lateral edges of the circumscribed area are free of surface layer tissue which is harder to cut at an angle to the layer. Lateral cutting of the corneal tissue which extends above the groove is a perfect cut of a cylindrical slice with use of a cylindrical trephine. To form a hinged layer the lateral cutting is terminated before completion with the remaining tissue functioning as the hinge. Epithelium tissue is not carried into the slice or interface of the cut tissue and stroma. |
