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A duochrome test is a test commonly used to refine the final sphere in refraction (undercorrection and overcorrection), which makes use of the longitudinal chromatic aberration of the eye.
Principle of binocular vision with horopter shown. In biology, binocular vision is a type of vision in which an animal has two eyes capable of facing the same direction to perceive a single three-dimensional image of its surroundings. Binocular vision does not typically refer to vision where an animal has eyes on opposite sides of its head and ...
Stereoacuity is defined as the minimum angle detectable, calculated as the difference between the angles subtended by both positions, A and B. Stereoacuity is possible due to binocular disparity, i.e., the difference in their binocular parallax.
Given as the first number in a binocular description (e.g., 7×35, 10×50), magnification is the ratio of the focal length of the objective divided by the focal length of the eyepiece. This gives the magnifying power of binoculars (sometimes expressed as "diameters").
The largest letter on an eye chart often represents an acuity of 6/60 (20/200), the value that is considered "legally blind" in the US. Many individuals with high myopia cannot read the large E without glasses, but can read the 6/6 (20/20) line or 6/4.5 (20/15) line with glasses. By contrast, legally blind individuals have a visual acuity of 6/ ...
Distance PD is the separation between the visual axes of the eyes in their primary position, as the subject fixates on an infinitely distant object. [2] Near PD is the separation between the visual axes of the eyes, at the plane of the spectacle lenses, as the subject fixates on a near object at the intended working distance. [3]
The Worth Four Light Test, also known as the Worth's four dot test or W4LT, is a clinical test mainly used for assessing a patient's degree of binocular vision and binocular single vision. Binocular vision involves an image being projected by each eye simultaneously into an area in space and being fused into a single image.
The binocular device is a generally compact instrument for both eyes designed for mobile use. A camera could be considered a type of optical instrument, with the pinhole camera and camera obscura being very simple examples of such devices.