Errors of refraction are, it is true, less common, especially myopia.

It can be caused by unequal errors of refraction, ocular misalignment, or cloudiness in the line of vision due to conditions such as cataracts.

In this way the ophthalmologist can estimate the maximum improvement in a patient's vision that can be attained by lenses to correct errors of refraction.

The most common forms of vision impairment are errors of refraction - the way light rays are focused inside the eye so images can be transmitted to the brain.

Because light passes only through the center of the eye's lens, defects in the shape of the lens (errors of refraction) have no effect while the occluder is used.

He asserted that "all errors of refraction and all functional disturbances of the eye disappear when it sees by central fixation" and that other conditions were often relieved as well.

Here is what Dr. Bates had to say about its importance: "Not only do all errors of refraction and all functional disturbances of the eye disappear when it sees by central fixation, but many organic conditions are relieved.

"The origin of any error of refraction," he wrote, "of a squint, or of any other functional disturbance of the eye, is simply a thought-a wrong thought-and its disappearance is as quick as the thought that relaxes.

In the early part of the day our forty-two guns, working furiously, though with a want of accuracy which may be due to those errors of refraction which are said to be common in the limpid air of the veld, preserved their superiority.

The country over which French was operating is dotted with those singular kopjes which the Boer loves--kopjes which are often so grotesque in shape that one feels as if they must be due to some error of refraction when one looks at them.