Melles G R, Binder P S
Ophthalmology Research Laboratory, Sharp Cabrillo Hospital, San Diego, Calif 92110.
Refract Corneal Surg. 1990 Nov-Dec;6(6):394-403.
The majority of ophthalmic surgeons who perform radial keratotomy make incisions from the optical clear zone to the limbus (downhill; centrifugal), instead of from the limbus to the optical clear zone (uphill; centripetal). To compare the efficacy of these techniques, one surgeon performed keratotomy incisions in 10 eyes of 5 monkeys using the same double-edged diamond blade set to 80% of central pachometry. Four or eight centrifugal (downhill) and centripetal (uphill) incisions were made in each eye. Achieved incision depth was measured by light microscopy 2.5 to 8 months postoperative. Downhill incision depth averaged 46% (range 38% to 61%), whereas uphill incision depth averaged 74% (range 53% to 87%) (P less than .0005). In both groups, incision deviation from the perpendicular (lateral tilt error) was greatest adjacent to the optical clear zone (P less than .01). These differences may be explained by tilt error (forward or backward) or by the perpendicular front cutting action of a vertical blade being more effective than the angled blade.
大多数实施放射状角膜切开术的眼科外科医生是从光学透明区向角膜缘（向下；离心方向）做切口，而不是从角膜缘向光学透明区（向上；向心方向）做切口。为比较这些技术的效果，一名外科医生使用同一把设置为中央角膜厚度80%的双刃金刚石刀片，在5只猴子的10只眼睛上进行角膜切开术切口。每只眼睛做4个或8个离心（向下）和向心（向上）切口。术后2.5至8个月通过光学显微镜测量所达到的切口深度。向下切口深度平均为46%（范围38%至61%），而向上切口深度平均为74%（范围53%至87%）（P小于0.0005）。在两组中，切口偏离垂线（侧向倾斜误差）在光学透明区附近最大（P小于0.01）。这些差异可能由倾斜误差（向前或向后）解释，或者由垂直刀片的垂直向前切割动作比倾斜刀片更有效来解释。
