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blur

 
lack of sharpness in an x-ray image, usually due to patient motion.

blur

(blur) indistinctness, clouding, or fogging.
spectacle blur  the indistinct vision with spectacles occurring after removal of contact lenses, especially non–gas-permeable lenses; it is believed to result from chronic corneal hypoxia and edema.

blur 

1. Degradation of an image formed by an optical system as a result of lack of focusing, aberrations, diffusion of light, etc.
2. A pattern in which the border is indistinct. See lens flare; blurred vision.
blur back test See plus 1.00 D blur test.
blur circle A circular patch of light formed on the retina resulting from a point object whose image is focused either in front of, or behind the retina, or due to excessive aberrations of the optical system of the eye. The size of the blur circle increases with the distance of the ocular image from the retina and with the diameter of the pupil. Its diameter can be expressed in angular terms (in min arc) as
α = 3.48 ✕ ΧFd
where ΧF is the defocus (in dioptres) with respect to the object point, and d the pupil diameter (in mm) (Figs. B4 and B5). Example: An object at infinity is viewed by a 2 D uncorrected myope with a 4.0 mm pupil diameter, i.e. α = 3.48 ✕ 2 ✕ 4 = 28 min arc. Syn. circle of confusion; circle of diffusion. See aberration; depth of field.
plus 1.00D blur test See plus 1.00 D blur test.
blur point See blur point.
spectacle blur Reduction in visual acuity noticed with spectacles after removal of hard contact lenses (PMMA). This may be due to corneal oedema, alteration of the corneal index of refraction, surface distortion of the cornea, etc. Refitting the patient with gas permeable lenses usually relieves this symptom.
Fig. B4 Blur circle corresponding to an image formed in front of the retinaenlarge picture
Fig. B4 Blur circle corresponding to an image formed in front of the retina
Fig. B5 Effect of pupil size on the blur circle. O9 is the image of object O formed by the optics of the eyeenlarge picture
Fig. B5 Effect of pupil size on the blur circle. O9 is the image of object O formed by the optics of the eye

blur

lack of clarity in the radiograph caused by movement of the x-ray tube, subject or film during exposure.

Patient discussion about blur

Q. My vision is blurry and I see zigzag lines, what is it from? Every now and again, usually after sitting a few hours in front of the computer or not sleeping enough at night, I start getting blurry vision. I see zigzag lines in front of my eyes and it can take sometimes an hour to go away. What is this from?

A. It sounds like you have a migraine. A migraine that comes with blurry vision and zigzags (an aura) is called a classic migraine. The aura of migraine typically lasts from 20 minutes to an hour. Some patients have prolonged aura symptoms that can last hours to days. The aura also typically ends before the headache itself begins. When migraine aura symptoms are prolonged or last into or through the headache phase these types of migraine are commonly referred to as complicated migraines.

Q. I have fibromyalgia and am having terrible vision problems...double, blurred, feel off blance.Is this common?

A. Blurry vision is not a usual symptom in fibromyalgia. If you are experiencing this on a permenant basis you should see a doctor- either a neurologist or an ophthalmologist to rule out other vision conditions that might be causing this.

Q. What are the sides effects of alcoholism beside dizziness and blur?

A. In the short term, excessive alcohol consumption may cause vomiting and metabolic disturbances, seizures and coma. In the long term, alcohol may damage the pancreas, liver and other organs, and expose to cancer of the mouth.

You may read more here:
www.nlm.nih.gov/medlineplus/alcoholism.html

More discussions about blur
References in periodicals archive ?
As a general rule of thumb, the lower the f-stop, the blurrier the background, and the effect is accentuated by getting closer to your subject.
Regardless of the changes that these developments may bring, there are three things that participants in the financial reporting supply chain can do to keep the public-private entity distinction from becoming blurrier than it already is.
This is unconventional--one expects hadith alongside Qur'an in the first chapter--but effective, especially for the formative period, where the line between hadith and fiqh is much blurrier than it is later.
The goal of "integration," like "freedom" for the anti-colonialists, stands like a great shining blur down at the far end of the struggle road, drawing and inspiring all who fight for it, but becoming not clearer but blurrier the closer one gets to it.
When we perceive visual cues, we have a very small area (fovea) in which objects are in focus and a much larger, but blurrier peripheral area (parafovea), which does not cover the entire field of vision.
Introduce a global dimension to the professional profile and the definition of supply chain becomes even blurrier.
What began as an ostensibly simple representation thus becomes successively blurrier as the text progresses and as parenthetical expressions make readers question what they are reading, who is presenting it, and ultimately, what they should believe.
The boundaries between sex and ice cream grew blurrier this year thanks to another sensual effort from Haagen-Dazs, a tour de force in delayed gratification.
The line between indie rock and jam band becomes blurrier each year.
At this phase in life, it not only defines lips (the contours of which can become blurrier with the years), but it helps prevent lipstick from 'travelling' into feathered lines.
LIP PENCIL: It not only defines lips (the contours of which can become blurrier with the years), but it helps prevent lipstick from "travelling" into feathered lines.
More and more, as the boundaries between public/private and ordinary/extraordinary get blurrier, the actions of female celebrities are hyper-magnified for the individual's consumptive pleasure and scorn which has not gone unnoticed by scholars and journalists alike.