Andrade H A, McDonald M B, Liu J C, Abdelmegeed M, Varnell R, Sunderland G
LSU Eye Center, Louisiana State University Medical Center School of Medicine, New Orleans 70112-2234.
Refract Corneal Surg. 1990 Sep-Oct;6(5):346-51.
The appearance of haze in the central cornea following photoablation with a 193 nm excimer laser is an important factor in the postoperative course of this procedure. Data from 37 human eyes treated with photorefractive keratectomy, 4 eyes treated with phototherapeutic keratectomy, and 5 untreated eyes were used to evaluate the ability of a commercially available opacity lensometer to provide an objective measure of corneal clarity. We found that the opacity lensometer was able to detect light scattered from the cornea but was not sufficiently sensitive to distinguish reliably among excimer-treated eyes with degrees of corneal haze evaluated as clear, trace, or 1+ by slit-lamp microscope examination. In untreated, clear corneas, the values obtained with the opacity lensometer in eyes measured with and without a clear contact lens were within one unit of each other for any given eye, but values from eye to eye varied over a range of six units. In a test simulating different amounts of corneal haze using contact lenses evenly coated with nail polish enamel, the log-transformed opacity lensometer values varied directly with percent light scattering as determined by spectrophotometry. These results suggest that the opacity lensometer measurements are reliable and reproducible, but that in the human cornea something is being measured by the opacity lensometer that is not taken into account in clinical slit-lamp microscope evaluation. Overall, it appears that, in its present form, this instrument is not useful to measure corneal clarity after excimer laser photoablation.
用193纳米准分子激光进行光消融后中央角膜出现 haze 是该手术术后过程中的一个重要因素。来自37只接受准分子原位角膜磨镶术治疗的人眼、4只接受光治疗性角膜切削术治疗的眼睛以及5只未治疗眼睛的数据，用于评估一种市售的不透明度晶状体计提供角膜清晰度客观测量的能力。我们发现，不透明度晶状体计能够检测到从角膜散射的光，但对于通过裂隙灯显微镜检查评估为清晰、微量或1+角膜 haze 程度的准分子激光治疗眼，其区分能力不够灵敏，无法可靠地区分。在未治疗的透明角膜中，对于任何给定的眼睛，在佩戴和不佩戴透明隐形眼镜测量时，不透明度晶状体计获得的值彼此相差在一个单位以内，但不同眼睛之间的值在六个单位的范围内变化。在一项使用均匀涂有指甲油漆的隐形眼镜模拟不同量角膜 haze 的测试中，经对数转换的不透明度晶状体计值与分光光度法测定的光散射百分比直接相关。这些结果表明，不透明度晶状体计测量是可靠且可重复的，但在人眼中，不透明度晶状体计所测量的某些东西在临床裂隙灯显微镜评估中未被考虑在内。总体而言，就其目前的形式而言，该仪器似乎对测量准分子激光光消融后的角膜清晰度无用。
