Negative relative accommodation
- Negative relative accommodation
-
Negative relative accommodation (NRA) was proposed by Prof. Joseph Kearney of Oxford University in 1967, is a measure of the maximum ability to relax accommodation while maintaining clear, single binocular vision.[1] This measurement is typically obtained by an orthoptist, ophthalmologist or optometrist during an eye examination using a phoropter. After the patient's distance correction is established, he or she is instructed to view small letters on a card 40 cm from the eyes. The examiner adds lenses in +0.25 increments until the patient first reports that they become blurry. The total value of the lenses added to reach this point is the NRA value.
See also
References
Wikimedia Foundation.
2010.
Look at other dictionaries:
Positive relative accommodation — (PRA) is a measure of the maximum ability to stimulate accommodation while maintaining clear, single binocular vision [http://www.vision therapy.com/Glossary of Terms.htm] . This measurement is typically obtained by an ophthalmologist or… … Wikipedia
Accommodation (eye) — Accommodation is the process by which the increases optical power to maintain a clear image (focus) on an object as it draws near the eye. The young human eye can change focus from distance to 7 cm from the eye in 350 milliseconds. This dramatic… … Wikipedia
Amplitude of accommodation — (AA) is a measurement of the eye’s ability to focus clearly on objects at near distances (i.e. accommodation). This eye focusing range for a child is usually about 5 ndash;7.5 cm (2 ndash;3 inches). For a young adult, it is 10 ndash;15 cm (4… … Wikipedia
Spasm of accommodation — A spasm of accommodation (also known as an accommodation, or accommodative, spasm) is a condition in which the ciliary muscle of the eye remains in a constant state of contraction. Normally, this contraction bends the lens to allow the eye to… … Wikipedia
Accommodation — In medicine, the ability of the eye to change its focus from distant to near objects (and vice versa). This process is achieved by the lens changing its shape. Accommodation is the adjustment of the optics of the eye to keep an object in focus on … Medical dictionary
Contingency theory of accommodation — The contingency theory of accommodation was proposed in 1997 by Amanda Cancel, Glen Cameron, Lynne Sallot and Michel Mitrook to highlight the pertinent factors of how a public relations practitioner facilitates communication between the… … Wikipedia
Eyeglass prescription — Using a phoropter to determine a prescription for eyeglasses An eyeglass prescription is an order written by an eyewear prescriber, such as an optometrist or ophthalmologist, that specifies the value of all parameters the prescriber has deemed… … Wikipedia
Eye examination — An eye examination is a battery of tests performed by an optometrist or ophthalmologist assessing vision and ability to focus on and discern objects, as well as other tests and examinations pertaining to the eyes.All people should have periodic… … Wikipedia
Convergence insufficiency — Convergence Insufficency Classification and external resources ICD 10 H51.1 ICD 9 378.83 … Wikipedia
Prism (optics) — For other uses, see Prism (disambiguation). A plastic prism In optics, a prism is a transparent optical element with flat, polished surfaces that refract light. The exact angles between the surfaces depend on the application. The traditional… … Wikipedia
