Binder P S, Moore M, Lambert R W, Seagrist D M
Ophthalmology Research Laboratory, National Vision Research Institute, San Diego, CA 92122, USA.
J Refract Surg. 1997 Mar-Apr;13(2):142-53. doi: 10.3928/1081-597X-19970301-10.
Microkeratomes are currently used for keratomiluesis in situ (automated lamellar keratoplasty) for myopia and hyperopia and for laser in situ keratomileusis (LASIK). Visual and refractive complications have been reported with these refractive surgical procedures. We compared two microkeratomes in their ability to resect corneal lamellae to gain insight into possible mechanism(s) of refractive and visual complications following lamellar refractive procedures.
Using an eyebank eye model, we performed automated lamellar keratoplasty to theoretically correct 10.00 diopters (D) of myopia using the Automated Corneal Shaper, manufactured by Chiron, Inc. and the MicroPrecision microkeratome, manufactured by Eye Technology, Inc. Diameters before (wet) and after fixation, thicknesses of excised tissue, and scanning electron microscopy were measured in a masked evaluation to compare instruments. Ultrasonic corneal pachymetry and a mechanical tissue compression gauge were also used to assess thickness of excised tissue.
The Chiron automated corneal shaper created blade chatter marks at the edges of all excisions, smaller than anticipated excision diameters, and a wide range of tissue thicknesses. In contrast, the MicroPrecision microkeratome created smoother resections of all tissues without creating blade marks; tissue diameters and thicknesses were closer to the intended dimensions compared to the Chiron automated corneal shaper.
Different microkeratomes create different morphologic features as they excise corneal tissue. Differences in instrument design, mechanics of the tissue excision and blade oscillation, and instrument traverse combined with surgical skill influence the configuration of lamellar keratotomies.
微型角膜刀目前用于近视和远视的原位角膜磨镶术（自动板层角膜移植术）以及准分子激光原位角膜磨镶术（LASIK）。这些屈光手术已报道了视觉和屈光并发症。我们比较了两种微型角膜刀切除角膜瓣的能力，以深入了解板层屈光手术后屈光和视觉并发症的可能机制。
使用眼库眼球模型，我们使用Chiron公司生产的自动角膜成型器和Eye Technology公司生产的MicroPrecision微型角膜刀进行自动板层角膜移植术，理论上矫正10.00屈光度（D）的近视。在盲法评估中测量固定前后的直径、切除组织的厚度和扫描电子显微镜，以比较器械。还使用超声角膜测厚仪和机械组织压缩计评估切除组织的厚度。
Chiron自动角膜成型器在所有切除边缘产生刀片颤动痕迹，切除直径小于预期，组织厚度范围广泛。相比之下，MicroPrecision微型角膜刀对所有组织的切除更平滑，没有产生刀片痕迹；与Chiron自动角膜成型器相比，组织直径和厚度更接近预期尺寸。
不同的微型角膜刀在切除角膜组织时产生不同的形态特征。器械设计、组织切除和刀片振荡的力学以及器械移动与手术技巧的差异会影响板层角膜切开术的形态。
