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Arteriole–venue ratio BIO: Binocular indirect ophthalmoscopy BSV: 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 ...
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 ...
Ophthalmology ( / ˌɒfθælˈmɒlədʒi /, OFF-thal-MOL-ə-jee) [ 1] is a clinical and surgical specialty within medicine that deals with the diagnosis and treatment of eye disorders. [ 2] A former term is oculism . An ophthalmologist is a physician who undergoes subspecialty training in medical and surgical eye care. [ 3]
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 term "optometry" comes from the Greek words ὄψις (opsis; "view") and μέτρον (metron; "something used to measure", "measure", "rule").The word entered the language when the instrument for measuring vision was called an optometer, (before the terms phoropter or refractor were used).
Cataract surgery is the most common application of lens removal surgery, and is usually associated with lens replacement. It is used to remove the natural lens of the eye when it has developed a cataract, a cloudy area in the lens that causes visual impairment. [ 4][ 10] Cataracts usually develop slowly and can affect one or both eyes. [ 4]
77664. Anatomical terminology. [ edit on Wikidata] The optic cup is the white, cup-like area in the center of the optic disc. [ 1] The ratio of the size of the optic cup to the optic disc (cup-to-disc ratio, or C/D) is one measure used in the diagnosis of glaucoma. Different C/Ds can be measured horizontally or vertically in the same patient.
An example of the Landolt C eye chart (also known as the Japanese eye chart.). Numerous types of eye charts exist and are used in various situations. For example, the Snellen chart is designed for use at 6 meters or 20 feet, and is thus appropriate for testing distance vision, while the ETDRS chart is designed for use at 4 meters. [16]