61.   How far can the human eye really see?

62.   In fact, these stars emit so little optical light that they seem, to the human eye, to disappear.

63.   In the distance, far beyond the reach of human eyes, are barrier islands with names like Ocracoke and Hatteras.

64.   In theory, the flash could blind human eyes.

65.   Its digital watermarks are designed not to be perceptible to the human eye.

66.   Many inspectors say that high-tech gear is nice but that human eyes and instinct still make the difference.

67.   On this morning, wisps of clouds floated across their lairs, shielding them from human eyes.

68.   One common ploy addresses the relative insensitivity of the human eye to the color blue.

69.   One problem with rendering such images in the past was that the computers always created razor-sharp images, which looked unnatural to the human eye.

70.   Other scientists already are toying with that technique to replace retinal cells in the human eye.