Bởi vì bản chất kiên cường của giác mạc và màng cứng, khâu những mô này đòi hỏi phải có vị trí cực kỳ chính xác của chỉ khâu. Theo dõi kim phải cắt giảm thông qua các lá mỏng của mô. Vết thương phẫu thuật có thể được đặt để tạo điều kiện thuận lợi cho việc đóng cửa | 6 Larry Benjamin Corneal Wounds and Repair Because of the unyielding nature of the cornea and sclera suturing of these tissues requires extremely precise placement of sutures. The needle track must cut through the lamellae of the tissue. Surgical wounds can be placed to facilitate closure whereas traumatic wounds often require thinking on one s feet at the time of repair because of their unpredictable architecture. Sometimes a surgical wound becomes difficult to close predictably for example overenlarging a phacoemulsification tunnel to insert an implant may destabilize a supposedly self-sealing wound and necessitate suturing. Examples of wound architecture and closure techniques for cataract wounds are detailed in Chap. 4. In order for a wound to be self-sealing it must create a valve-like effect. Closing the Large Limbal Wound This can be done with interrupted sutures or a continuous one. The theoretical advantage of a continuous suture is the more even distribution of tension along the length of the wound and thus hopefully less astigmatism. However a tight continuous suture can cause just as much astigmatism as interrupted ones and also have the disadvantage of being less flexible in terms of astigmatism control. If it breaks or loosens the whole thing must be removed and possibly replaced whereas selective removal of individual sutures can be useful to adjust astigmatism. Assuming that the wound has been made 1 mm from the limbus and is beveled then placement of the first 10-0 nylon suture is made centrally. The principle of this stitch is that it is used to stop the wound from opening as opposed to keeping it closed. In principle the wound will if well constructed keep itself closed and should heal with no astigmatism if left undisturbed. Clearly patients cannot be asked to keep still for several weeks while the wound is healing and so sutures are placed to keep the wound from opening. If this suture does not equally divide the wound it will need to
