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Topic: Intraocular pressure


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In the News (Sun 29 Nov 09)

  
  Daytime Normal Intraocular Pressure May Rise Sharply at Night - CME Teaching Brief® - MedPage Today
Be aware that this study suggests that intraocular pressure measured during the day in a sitting position may not give an accurate overall picture of the patient's intraocular pressure.
Intraocular pressure may rise when a patient is lying in bed at night because of the change in vertical distance between the eye and the heart, which alters the local orbital blood pressure and the ocular perfusion pressures, the investigators speculated.
A clinical implication of the Japanese study "is that the peak intraocular pressure in a glaucoma patient often cannot be detected during office hours or even during the entire diurnal/awake period," said Dr. Weinreb.
www.medpagetoday.com /Surgery/Ophthalmology/tb/2666   (533 words)

  
 Encyclopedia - Intraocular Pressure (IOP)
Intraocular pressure is a measurement of the fluid pressure inside the eye.
Pressure that is consistently above 21 indicates ocular hypertension.
Intraocular pressure is measured with an instrument called a tonometer.
www.visionrx.com /library/enc/enc_iop.asp   (299 words)

  
 Device and method for regulating intraocular pressure - Patent 5713844
The method of claim 11 wherein said volume of said exogenous fluid is determined by measuring intraocular pressure and using a nomogram to correlate volume of exogenous fluid with pressure exerted on said interior tube wall.
The volume of the exogenous fluid is determined by measuring the intraocular pressure and using a nomogram to correlate volume of the exogenous fluid with the pressure exerted on the interior tube wall.
Whenever the intraocular pressure is determined to be outside the desired range, it may be regulated by the following simple procedure: a local anesthetic is administered to the eye, preferably in the form of eye drops, then exogenous fluid 44 is added to the exterior tube 14.
www.freepatentsonline.com /5713844.html   (2627 words)

  
 GLAUCOMA
Glaucoma is an eye disorder in which an intraocular pressure that is too high for the health of the eye causes the optic disc to become cupped and atrophic and the visual field to develop characteristic nerve fiber bundle defects.
The reason for the predisposition to central retinal vein occlusion in glaucoma is the influence of intraocular pressure on venous pressure and caliber, particularly at the point at which the veins exit from the eye.
Several measurements of intraocular pressure are spaced at intervals throughout the day, usually in an attempt to find the peak pressure of the diurnal variation in a patient suspected of having glaucoma or to determine if a treatment regimen is successfully controlling intraocular pressure throughout the day.
www.geocities.com /webmed_olho/glaucoma.htm   (3441 words)

  
 Intraocular pressure - Wikipedia, the free encyclopedia
Intraocular pressure (IOP) is the fluid pressure inside the eye.
Differences between the pressure in the two eyes is often clinically significant, and potentially associated with certain types of glaucoma, as well as iritis or retinal detachment.
Intraocular pressure is determined by the coupling of the production of aqueous humor from the eye's ciliary body and its drainage through the trabecular meshwork and Schlemm's canal located in the anterior chamber angle.
en.wikipedia.org /wiki/Intraocular_pressure   (217 words)

  
 Spontaneous retinal venous pulsation: aetiology and significance -- Jacks and Miller 74 (1): 7 -- Journal of Neurology, ...
Intraocular pulse pressure is 3 mm Hg and retrolaminar pulse pressure is 1 mm Hg.
As the intraocular and retrolaminar retinal venous pressure vary by the same amount with the cardiac cycle, there is no longer a variation in the pressure gradient in the retinal vein across the lamina cribrosa, flow of blood from the eye does not vary with the cardiac cycle, and retinal venous pulsations cease.
in the pulse pressure gradient from the intraocular to the retrolaminar
jnnp.bmj.com /cgi/content/full/74/1/7   (1692 words)

  
 Glaucoma patients appear to have increased eye pressure during sleep
Higher intraocular pressure, the force within the eyeball, and greater daily fluctuation in pressure may increase the risk that glaucoma will develop or worsen.
Intraocular pressure is usually measured during regular physician's visits, when patients are seated, according to background information in the article.
The average peak pressure for seated patients was 16 mm Hg; for those lying down, it was 18.9 mm Hg; and the peak reproduced pressure was 17.5 mm Hg.
www.eurekalert.org /pub_releases/2006-02/jaaj-gpa020906.php   (425 words)

  
 The BC Compassion Club Society - Effect of Marihuana on Intraocular and Blood Pressure in Glaucoma
Intraocular pressures were then measured with a Goldmann applanation tonometer mounted onto a Haag-Streit slit lamp.
In several patients the maximum decrease in blood pressure occurred within 10 to 15 minutes and was accompanied by postural hypotension in five cases.
The subject was immediately placed in the reclining position with the blood pressure rising to 110 mm Hg and IOP increased to 5 mm Hg in the right eye and 41 mm Hg in the left eye as measured with a hand-held applanation tonometer (Fig).
www.thecompassionclub.org /medical/research/03/31/17_0603311341-876   (1869 words)

  
 :::: | Glaucoma Consutants of East Texas | :::::
Precise data are lacking, but pressure elevations as small as a 50% increase (i.e., 20 to 30 mmHg) for 1 month can be expected to cause a permanent worsening of disc damage in patients with serious disc damage present prior to the pressure elevation.
The pressure at which a patient has developed a hemorrhage of the optic disc or at which progressive disc damage or visual field loss has been noted to occur prior to cataract extraction gives a rough estimate of the level of IOP the optic nerve is able to tolerate.
In contrast, a patient who develops a disc hemorrhage when intraocular pressures are averaging around 25 mmHg probably has an optic disc that is more resistant to the damaging effects of IOP and may tolerate a pressure up to 25 mmHg.
www.eyesoftexas.us /info/extraction.htm   (1758 words)

  
 eMedicine - Glaucoma, Intraocular Tumors : Article by Andrew A Dahl, MD   (Site not responding. Last check: 2007-09-18)
This is in contrast to 50% incidence of increased intraocular pressure in eyes enucleated for tumors.
Different mechanisms for elevated intraocular pressure have been proposed, as follows: (1) direct infiltration of the angle tissue, (2) secondary angle closure due to ciliary body and choroid thickening, (3) fibrovascular membrane formation over the angle, and (4) anterior chamber dysgenesis.
Elevated intraocular pressure results from either outflow obstruction secondary to iritis, hyphema, pseudohypopyon, or leukemic infiltration of the trabecular meshwork and Schlemm canal, as well as episcleral tissue, which may involve aqueous veins.
www.emedicine.com /oph/topic143.htm   (2567 words)

  
 MedlinePlus Medical Encyclopedia: Tonometry
Tonometry is a procedure that measures the pressure inside the eyes.
The test is used to screen for glaucoma, a disease in which pressure inside the eyes increases to the point that it impairs vision.
The instrument calculates pressure from the change in the light reflected off the corneas as the air puff is blown.
www.nlm.nih.gov /medlineplus/ency/article/003447.htm   (629 words)

  
 Effect of plasma colloid osmotic pressure on intraocular pressure during haemodialysis -- Tokuyama et al. 82 (7): 751 ...
The mechanism for the correction of a massive accumulation of fluid in the interstitial compartment, and for the reduction in intraocular pressure is illustrated.
As a consequence, plasma colloid osmotic pressure undergoes a relative increase in response to the decrease in plasma volume, because large proteins, such as albumin and globulin, cannot cross the membranes.
A gradient of colloid osmotic pressure between plasma and interstitial fluid (or aqueous humour) causes a net movement of water from the interstitial fluid (or aqueous humour) into the plasma.
bjo.bmjjournals.com /cgi/content/full/82/7/751   (1617 words)

  
 Intraocular Pressure (IOP) - TRAVATAN® Ophthalmic solution // Consumers & Patients   (Site not responding. Last check: 2007-09-18)
Glaucoma damage is most often the result of the aqueous humor passing too slowly through the trabecular meshwork drainage system, increasing the pressure inside the eye.
But a pressure of 22 or higher is considered suspicious and possibly abnormal.
It depends on the level of pressure that your optic nerve—that bundle of 1.2 million nerve fibers that transmits images from your eye to your brain—can tolerate without being damaged.
www.travatan.com /consumer/IOP.asp   (448 words)

  
 Ocular Hypertension
An intraocular pressure of greater than 21 mm Hg is measured in one or both eyes on 2 or more occasions.
Pressure inside the eye is measured using an instrument called a tonometer.
To determine other possible causes for your high eye pressure, an ophthalmologist (a medical doctor who specializes in eye care and surgery) assesses whether your drainage system (called the "angle") is open or closed.
www.emedicinehealth.com /ocular_hypertension/article_em.htm   (1072 words)

  
 Untitled Document   (Site not responding. Last check: 2007-09-18)
Glaucoma is the consequence of a blockage of the outflow of aqueous humor and a subsequent buildup of pressure inside the eye.
The diagnosis of glaucoma is based on history, clinical signs, measuring the intraocular pressure [tonometry] and visually examining the drainage angle using a process known as gonioscopy.
A side-effect was the pronounced reduction of the intraocular pressure.
www.gvsvet.com /glaucoma.htm   (2113 words)

  
 Other Topics: Glaucoma - The Perils of High Pressure
Glaucoma is the name given to the group of diseases that usually involve high intraocular pressure and produce optic nerve damage.
Though eye pressure is not connected to blood pressure, the presence of high blood pressure can worsen the harmful effects of elevated intraocular pressure.
Intraocular pressures will often exceed 50 mm of mercury and this is a true medical emergency to be treated medically with a laser or surgically making a slit to allow drainage.
www.thedoctorwillseeyounow.com /articles/other/glauc_32   (1594 words)

  
 Iminoimidazolidines useful in lowering intraocular pressure - Patent 4801617
A topical ophthalmic composition useful in the treatment of elevated intraocular pressure, comprising an effective amount of a compound selected from compounds of formula: ##STR17## wherein R is ##STR18## and a pharmaceutically acceptable carrier therefor.
A method of lowering intraocular pressure in a mammalian host which comprises applying an ophthalmic composition according to claim 6 topically to the affected eye.
A method of lowering intraocular pressure in a mammalian host which comprises applying an ophthalmic composition according to claim 7 topically to the affected eye.
www.freepatentsonline.com /4801617.html   (3178 words)

  
 Wills Eye Health System - Glaucoma - Excellence in Eye Care
The pressure within the eye, the intraocular pressure, can directly damage the optic nerve, the nerve that carries the electrical impulses from the light-sensitive part of the eye to the brain, where the electrical impulses are put together to form a picture.
Elevated intraocular pressure can damage other tissues as well, such as the cornea and the lens, and can squeeze out of the eye the blood needed to keep the nerves healthy, resulting in damage to the nerves or retina (the light-sensitive part of the eye).
Average normal intraocular pressure in adults is 15 mm Hg (mercury).
www.willseye.org /patients/topics/glaucoma   (514 words)

  
 Honan Balloon
The optimum pressure to be used should be well below pressure in the central retinal artery.
on fragile sclerotic vessels when the intraocular pressure is suddenly reduced to atmospheric pressure at the time of incision.
Lowering the intraocular pressure by preoperative ocular compression should reduce the pressure differential and the amount of
www.honanballoon.com   (358 words)

  
 Relationship between intraocular pressure and obesity in Japan -- Mori et al. 29 (4): 661 -- International Journal of ...
Age-specific intraocular pressure and body mass index values are shown by the least square methods in the multiple linear regression model.
Intraocular pressure values are examined by ANCOVA controlled for age, gender, systolic blood pressure, and diastolic blood pressure.
Slope of intraocular pressure is shown by ANCOVA controlled for age, gender, initial body mass index, initial systolic blood pressure, slope of systolic blood pressure, initial diastolic blood pressure, slope of diastolic blood pressure, and initial intraocular pressure.
ije.oxfordjournals.org /cgi/content/full/29/4/661   (2531 words)

  
 Understanding Intraocular Pressure Glaucoma Service Foundation: Chat Highlights
Intraocular pressure is the pressure of the fluid inside the sclera, the white outer coat of the eye.
It does increase the partial pressure of oxygen and carbon dioxide in the blood, both of which would seem to be helpful for the glaucoma patient.
My only warning to divers is to practice care with hygiene in defogging their masks, and with mask squeeze and trauma to the eye if they have a trabeculectomy that is still working.
www.wills-glaucoma.org /supportgroup/20051123.htm   (1428 words)

  
 Measurement of intraocular pressure after epikeratophakia -- Wright and Grajewski 81 (6): 448 -- British Journal of ...
pressure was adjusted in 5 mm Hg increments from 0 to 50 mm Hg.
One needle was connected to a water column that could be raised and lowered to adjust the intraocular pressure.
The pressure in the eye was adjusted between 0 and 50 mm Hg, in 5 mm Hg intervals, by raising and lowering the water column.
bjo.bmj.com /cgi/content/full/81/6/448   (1990 words)

  
 Correlation between intraocular pressure and CD4+ T-lymphocyte counts in patients with human immunodeficiency virus ...
PURPOSE: To determine the intraocular pressure in patients with human immunodeficiency virus (HIV) with and without cytomegalovirus retinitis, and to correlate intraocular pressure with CD4+ T-lymphocyte count and the presence, extent, and activity of cytomegalovirus retinitis.
RESULTS: The mean intraocular pressure was 9.8 mm Hg in Group A, 12.6 mm Hg in Group B, and 16.1 mm Hg in the control group.
Knowledge of the normal range of intraocular pressure in patients with HIV will be important to the understanding and treatment of glaucoma and other disorders or treatments affecting intraocular pressure.
www.aegis.com /aidsline/1996/oct/M96A1195.html   (540 words)

  
 Intraocular pressure and systemic blood pressure: longitudinal perspective: the Beaver Dam Eye Study -- Klein et al. 89 ...
The influence of age and intraocular pressure on the optic cup in a normal population.
Determinants of intraocular pressure and its association with glaucomatous optic neuropathy in Chinese Singaporeans: the Tanjong Pagar Study.
The effect of intracamerally injected ethacrynic acid on intraocular pressure in patients with glaucoma.
bjo.bmjjournals.com /cgi/content/full/89/3/284   (2314 words)

  
 Eye Tests > Intraocular pressure -- EyeMDLink.com
The measurement of eye pressure is part of a routine eye examination in which the intraocular pressure, or pressure inside the eye, is determined.
This works on the principle that the force required to flatten a given area of the cornea is proportional to the pressure inside the eye.
Pneumo-tonometry, commonly known as the "puff test" by patients, is the least accurate method, and is rarely used by EyeMDs.
www.eyemdlink.com /Test.asp?TestID=16   (171 words)

  
 Glaucoma Information and Glaucoma Risk Factors
The initial target pressure is an estimate and a means toward the ultimate goal of protecting the optic nerve.
The adequacy and validity of the target pressure are periodically reassessed by comparing optic nerve status (by optic nerve appearance and visual field tests) with previous (including baseline) examinations.
In contrast, the diastolic perfusion pressure of the ocular tissues is an important factor in the development of glaucoma damage.
www.agingeye.net /glaucoma/glaucomainformation.php   (2620 words)

  
 Treatment of Increased Intraocular Pressure
The investigator randomizes treatment to eyes of patients with bilaterally increased intraocular pressure such that 50 patients are assigned to active treatment for their right eye and 50 patients are assigned active treatment for their left eye.
After one month of treatment the investigator measures the intraocular pressures in both eyes.
Inference: How can we use the study data to investigate whether there is a real difference in intraocular pressure between drug treated and placebo treated eyes for individuals with bilaterally increased intraocular pressure in the population from which the sample was selected?
connection.lww.com /products/riegelman/StudyAStudy/ss_2_01.html   (191 words)

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