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Binocular single vision: BV: Binocular vision: BVD: 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 ...
Humphrey field analyser ( HFA) is a tool for measuring the human visual field that is commonly used by optometrists, orthoptists and ophthalmologists, particularly for detecting monocular visual field. [ 1] The results of the analyser identify the type of vision defect. Therefore, it provides information regarding the location of any disease ...
Canine glaucoma refers to a group of diseases in dogs that affect the optic nerve and involve a loss of retinal ganglion cells in a characteristic pattern. An intraocular pressure greater than 22 mmHg (2.9 kPa) is a significant risk factor for the development of glaucoma. Untreated glaucoma in dogs leads to permanent damage of the optic nerve ...
Landolt C. Lea test. logMAR chart. An eye chart is a chart used to measure visual acuity comprising lines of optotypes in ranges of sizes. Optotypes are the letters or symbols shown on an eye chart. [ 1] Eye charts are often used by health care professionals, such as optometrists, physicians and nurses, to screen persons for vision impairment.
The Jaeger chart is an eye chart used in testing near visual acuity. It is a card on which paragraphs of text are printed, with the text sizes increasing from 0.37 mm to 2.5 mm. [ 1] This card is to be held by a patient at a fixed distance from the eye dependent on the J size being read. The smallest print that the patient can read determines ...
In the most familiar acuity test, a Snellen chart is placed at a standard distance: 6 metres. At this distance, the symbols on the line representing "normal" acuity subtend an angle of five minutes of arc, and the thickness of the lines and of the spaces between the lines subtends one minute of arc. This line, designated 6/6 (or 20/20), is the ...
Cats have excellent night vision and can see at one sixth the light level required for human vision. [ 53 ] : 43 This is partly the result of cat eyes having a tapetum lucidum , which reflects any light that passes through the retina back into the eye, thereby increasing the eye's sensitivity to dim light. [ 69 ]
The chart was designed by Ian Bailey [5] and Jan E. Lovie-Kitchin at the National Vision Research Institute of Australia. [1] [3] They described their motivation for designing the LogMAR chart as follows: "We have designed a series of near vision charts in which the typeface, size progression, size range, number of words per row and spacings were chosen in an endeavour to achieve a ...