Klett Z, Morris M, Gieser S C, Couch J M, Hirsch J
Department of Ophthalmology and Visual Science, Yale University School of Medicine, New Haven, Connecticut 06510.
J Cataract Refract Surg. 1991 Jan;17(1):45-57. doi: 10.1016/s0886-3350(13)80983-2.
The laser interferometer can effectively bypass the optics of the eye and measure retinal function in patients with immature cataracts. However, it is not known how much laser interferometric measurements are impaired by cataract density. In this study we compared objective lens opacity using the IntraOptics opacity lensmeter with contrast sensitivity (CS) measured by a Randwal He-Ne laser interferometer. Comparison of lens opacity with CS in the cataract population revealed an inverse linear relationship between objective lens opacity and retinal contrast sensitivity. Separation by cataract type showed correlation coefficients as high as -0.91 for nuclear sclerotic predominant cataracts and as low as no significant correlation for posterior subcapsular predominant cataracts. Comparisons of before and after implantation surgery contrast sensitivities (as measured by the laser interferometer) with preoperative lens opacities (as measured by the IntraOptics opacity lensmeter) quantified the extent to which laser interferometric measurements underestimated potential retinal function. We found that for all cataracts, other than posterior subcapsular predominant cataracts, potential contrast sensitivity (in decibels) was underestimated by about 0.2 to 0.3 times the opacity measured by this technique.
激光干涉仪能够有效绕过眼睛的光学结构，测量患有未成熟白内障患者的视网膜功能。然而，尚不清楚白内障密度会对激光干涉测量造成多大程度的损害。在本研究中，我们使用IntraOptics不透明度晶状体计比较客观晶状体混浊度与通过Randwal氦氖激光干涉仪测量的对比敏感度（CS）。在白内障人群中比较晶状体混浊度与对比敏感度，结果显示客观晶状体混浊度与视网膜对比敏感度之间呈负线性关系。按白内障类型区分，核性硬化为主的白内障相关系数高达-0.91，而后囊下为主的白内障相关系数低至无显著相关性。将植入手术前后的对比敏感度（通过激光干涉仪测量）与术前晶状体混浊度（通过IntraOptics不透明度晶状体计测量）进行比较，量化了激光干涉测量低估潜在视网膜功能的程度。我们发现，对于除后囊下为主的白内障以外的所有白内障，潜在对比敏感度（以分贝为单位）被低估了约为此技术测量的混浊度的0.2至0.3倍。
