Search results
Results From The WOW.Com Content Network
Vertex distance is the distance between the back surface of a corrective lens, i.e. glasses (spectacles) or contact lenses, and the front of the cornea. Increasing or decreasing the vertex distance changes the optical properties of the system, by moving the focal point forward or backward, effectively changing the power of the lens relative to ...
The eye relief of an optical instrument (such as a telescope, a microscope, or binoculars) is the distance from the last surface of an eyepiece within which the user's eye can obtain the full viewing angle. If a viewer's eye is outside this distance, a reduced field of view will be obtained.
BVD Back vertex distance is the distance between the back of the spectacle lens and the front of the cornea (the front surface of the eye). This is significant in higher prescriptions (usually beyond ±4.00D) as slight changes in the vertex distance for in this range can cause a power to be delivered to the eye other than what was prescribed.
In glasses with powers beyond ±4.00D, the vertex distance can affect the effective power of the glasses. [4] A shorter vertex distance can expand the field of view, but if the vertex distance is too small, the eyelashes will come into contact with the back of the lens, smudging the lens and causing annoyance for the wearer.
Back vertex distance BVP: Back vertex power CD: Centration distance C/D: Cup–disc ratio CF: Count fingers vision – state distance c/o or c.o. Complains of CT: Cover test c/u: Check up CW: Close work Δ: Prism dioptre D: Dioptres DC: Dioptres cylinder DNA: Did not attend DOB: Date of birth DS: Dioptres sphere DV: Distance vision DVD ...
Keeping the dog on an indoor tether that allows distance between the dog and guests. Keeping the dog in a crate. Keeping the dog in a dog-proofed room. Keeping the dog in a safely fenced yard.
Before commencing a Subjective Refraction, ensure that: The patient is seated at a 6-metre distance from the Snellen Chart. [3]The illumination in the testing room is at a comfortable level of brightness for an indoor setting [3]
Average CEO Pay is calculated using the last year a director sat on the board of each company. Stock returns do not include dividends. All directors refers to people who sat on the board of at least one Fortune 100 company between 2008 and 2012. The Pay Pals project relies on financial research conducted by the Center for Economic Policy and ...