Atebara N H, Miller D
Department of Ophthalmology, Beth Israel Hospital, Boston, MA 02215.
Am J Ophthalmol. 1990 Aug 15;110(2):172-7. doi: 10.1016/s0002-9394(14)76987-9.
We attempted to quantify the decrease in contrast associated with the concentric-style bifocal intraocular lens by using a model eye and bifocal intraocular lens, with a model unifocal intraocular lens as a control. When imaging near objects, pupils smaller than 2.5 mm produced image contrast of 100% of the control; larger pupils degraded contrast to 25% for a 6-mm pupil. For distant objects, pupils smaller than 2.5 mm produced image contrast of 70% to 95% because of the pinhole effect; larger pupils engaged the distance portion of the intraocular lens and maintain 80% contrast on average. Thus, the bifocal intraocular lens produced image contrast greater than 70% in all situations tested, except when imaging near objects with a pupil larger than 3.5 mm. The data suggest that image contrast is highly dependent on pupil size and object distance.
我们试图通过使用模型眼和双焦点人工晶状体，并以单焦点人工晶状体模型作为对照，来量化与同心式双焦点人工晶状体相关的对比度下降情况。在对近物成像时，小于2.5毫米的瞳孔产生的图像对比度为对照的100%；对于6毫米的瞳孔，较大的瞳孔会使对比度降至25%。对于远物，小于2.5毫米的瞳孔由于针孔效应产生的图像对比度为70%至95%；较大的瞳孔会启用人工晶状体的远用部分，平均保持80%的对比度。因此，除了在对瞳孔大于3.5毫米的近物成像时，双焦点人工晶状体在所有测试情况下产生的图像对比度均大于70%。数据表明，图像对比度高度依赖于瞳孔大小和物距。
