blur


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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 classic literature ?
while George fans her along over the white blur of the Banks in beautiful upward curves of fifty miles each.
I tried to look out of the windows to see something of where we were, but they were made of frosted glass, and I could make out nothing save the occasional bright blur of a passing light.
There were the two towers of Baskerville Hall, and there a distant blur of smoke which marked the village of Grimpen.
As we looked, we saw a dark blur moving across the blind.
Nevertheless he sat still a moment, straining his eyes down the long hill, for it was the most confusing hour of the evening, the hour when the last clearness from the upper sky is merged with the rising night in a blur that disguises landmarks and falsifies distances.
I could feel myself growing weaker and weaker, until at length objects commenced to blur before my eyes and I staggered and blundered about more asleep than awake, and then it was that he worked his pretty little coup that came near to losing me my life.
The colors are dimmed with age; the countenances are scaled and marred, and nearly all expression is gone from them; the hair is a dead blur upon the wall, and there is no life in the eyes.
Minerva said she hoped not; they were only ridiculous little creatures, with this odd circumstance, that they had a blur, or indeterminate aspect, seen far or seen near; if you called them bad, they would appear so; if you called them good, they would appear so; and there was no one person or action among them, which would not puzzle her owl, much more all Olympus, to know whether it was fundamentally bad or good.
Sir Richard looked at Robin until something arose in his eyes that made all the lights and the faces blur together.
beneath it was green and dim, and it grew dimmer and dimmer until the sand at the bottom was only a pale blur.
We must hide our canoes," explained Ja, "for the Mezops of Luana are always at war with us and would steal them if they found them," he nodded toward an island farther out at sea, and at so great a distance that it seemed but a blur hanging in the distant sky.
Cheated passion cast a red blur before the eyes of the Belgian.