穿孔角膜成形术是一种广泛应用的治疗角膜混浊的外科手术。该手术用环钻进行。环钻通常为一圆形切割器,可除去患者眼内的混浊角膜,也可取出供眼者同样大小的清澄角膜移植物,使之缝合到接受者的角膜上。通常的环钻,不论是机械的还是非机械的,都用手工操作。这种手术的并发症之一就是不能控制角膜穿孔而损伤眼内结构,如虹膜和晶状体。为避免这些并发症,很多外科医生使用环钻时只在角膜上钻一深槽,用刀和剪刀割去混浊的角膜,造成患者眼内被切割的角膜边缘不齐。现在设计的是一种可控机械环钻,它能在角膜上作近乎完全圆形的切割,一当环钻穿透到眼的前 Perforating keratoplasty is a widely used surgical treatment of corneal opacity. The operation is performed with a trephine. A trephine is usually a circular cutter that removes the turbid cornea from the patient’s eye. A clear corneal graft of the same size for the donor can also be removed and stitched to the recipient’s cornea. The usual trephine, either mechanical or non-mechanical, are hand operated. One of the complications of this procedure is the inability to control perforation of the cornea to damage the intraocular structures such as the iris and the lens. To avoid these complications, many surgeons use a trephine to drill a deep groove in the cornea, remove the cloudy cornea with a knife and scissors, causing the incised corneal margins in the patient’s eye to be misaligned. What is now being designed is a controlled mechanical trephine that can make a near-perfect cut on the cornea, and once the trephine penetrates the eye