retinografie

8/10/2019 retinografie

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Retinography

A retinography is a photographic image of the fundus ocularis. This image can be obtained with

a fundus camera or with laser scan tools, and the procedure is usually carried out after

administering mydriatic eye drops, although there currently are instruments that make it

possible to obtain such an image even without dilating the pupil. Traditional retinographyproduces a colour image of the ocular fundus, which is generally used in the screening of

certain ocular pathologies, such as diabetic retinopathy, or for monitoring, as in the case of

choroidal nevi. There are also other types of retinography, each of which is suited for studying

certain aspects in more detail: red-free light retinography (vessels, haemorrhages, drusen,

exudates), blue-green light retinography (nervous fibre layer, inner limiting membrane, folds,

retinal cysts, epiretinal membrane) and red-light retinography (pigmented lesions, ruptured

choroid, choroidal vessels).

Retinografia

Un retinografia este o imagine fotografic a fundului de ochi Ocularis . Aceast imagineobinut cu un fund POATE FI camer sau cu instrumente de scanare cu laser , iar procedura

este efectuat, de obicei dup administrarea picturi pentru ochi midriatice , dei n prezent,

exist dispune de instrumente face posibil obinerea acel an Basescu dilatarea imaginea elev

chiar i fr . Retinography tradiional produce o imagine color a fundului ocular , care este n

general folosit n screeningul Anumite patologiilor oculare , Cum ar fi retinopatia diabetic , sau

pentru monitorizarea , ca i n cazul nevi coroid . Exist i alte tipuri de retinography , fiecare

dintre care este potrivit pentru a studia anumite aspecte mai detaliat : red- lumina retinography

gratuit ( Vase , hemoragii , drusen , exudate ) , albastru -Verde retinography deschis ( strat de

fibre nervos , membrana limitarea interior , falduri , chisturi retiniene , membran epiretinal ) i

retinography rou -light ( leziuni pigmentate , coroida rupt , Recipientelor coroid ) .http://www.fondazionebietti.it/en/diagnostic_tests_and_procedures

Diabetic Retinopathy Defined

What is diabetic eye disease?

Diabetic eye disease refers to a group of eye problems that people with diabetes may face as a

complication of diabetes. All can cause severe vision loss or even blindness.

What is diabetic retinopathy?

Diabetic retinopathy is the most common diabetic eye disease and a leading cause of blindness in

American adults. It is caused by changes in the blood vessels of the retina.
http://www.fondazionebietti.it/en/diagnostic_tests_and_procedureshttp://www.fondazionebietti.it/en/diagnostic_tests_and_procedureshttp://www.fondazionebietti.it/en/diagnostic_tests_and_procedures


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In some people with diabetic retinopathy, blood vessels may swell and leak fluid. In other people,

abnormal new blood vessels grow on the surface of the retina. The retina is the light-sensitive tissue

at the back of the eye. A healthy retina is necessary for good vision.

If you have diabetic retinopathy, at first you may not notice changes to your vision. But over time,

diabetic retinopathy can get worse and cause vision loss. Diabetic retinopathy usually affectsboth eyes.

Causes and Risk Factors

How does diabetic retinopathy cause vision loss?

Blood vessels damaged from diabetic retinopathy can cause vision loss in two ways:

1. Fragile, abnormal blood vessels can develop and leak blood into the center of the eye,

blurring vision. This is proliferative retinopathyand is the fourth and most advanced stage

of the disease.

2. Fluid can leak into the center of the macula, the part of the eye where sharp, straight-ahead

vision occurs. The fluid makes the macula swell, blurring vision. This condition is

called macular edema.It can occur at any stage of diabetic retinopathy, although it is more

likely to occur as the disease progresses. About half of the people with proliferative

retinopathy also have macular edema.

Normal Vision and the same scene viewed by a person with diabetic retinopathy.

https://www.nei.nih.gov/health/diabetic/retinopathy

Symptoms of Diabetic Retinopathy

Diabetic retinopathy is usually silent. Severe and permanent retinal damage can occur

before you notice any of the following symptoms:

Blurred vision that does not improve with glasses

Vision that worsens, improves, then worsens again Sudden loss of vision, particularly following events such as coughing or sneezing

Seeing "cobwebs," "spots," or a "hole" in your field of vision

Eye pain
https://www.nei.nih.gov/health/diabetic/retinopathyhttps://www.nei.nih.gov/health/diabetic/retinopathyhttps://www.nei.nih.gov/health/diabetic/retinopathy


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A Closer Look at Diabetic RetinopathyIn this article

Symptoms of Diabetic RetinopathyShare this:

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Diabetic retinopathy is a common and potentially disabling long-term complication of

diabetes. This condition arises when elevated levels of blood sugar damage the tiny

blood vessels that supply oxygen and nutrients to the retina, the part of the eye that

detects light. Typically, both eyes are affected.

Retinopathy can also lead to glaucoma, increased pressure within the eye that can

further threaten vision. Untreated, retinopathy can lead to progressive and irreversible

vision loss. This condition is the leading cause of blindness in people between the agesof 20 and 60. But if retinopathy is diagnosed early, blindness can be prevented.

Although many people with diabetes develop impaired vision, fewer than 5% suffer

severe vision loss.

For a person who has diabetes, the risk of developing retinopathy is directly related to

the length of time that he or she has had diabetes. Both type 1 and type 2 diabetes can

lead to retinal damage. Although retinopathy usually does not appear for approximately

five years after a type 1 diabetes diagnosis, it may already be present when type 2

diabetes is diagnosed. After 15 years of having diabetes, 98 percent of those with type1 diabetes and 78 percent of those with type 2 have some degree of retinal damage.

http://www.webmd.com/diabetes/closer-look-diabetic-retinopathy

Retinography

Retinography is a sophisticated means for identifying people by the pattern of blood

vessels on the retina (the innermost coat of the back part of the eye). It requires the use

of a special scanner about the size of a shoe-box that can map the unique pattern of

blood vessels on the retina. The pattern is so complex that even identical twins do not

have the same blood vessel configuration. Those who favor its use claim retinography

has an error rate of only one in a million.
http://www.webmd.com/diabetes/closer-look-diabetic-retinopathy#1http://www.webmd.com/diabetes/closer-look-diabetic-retinopathy#1http://app.readspeaker.com/cgi-bin/rsent?customerid=5841&lang=en_us&readid=textArea&url=http://www.webmd.com/diabetes/closer-look-diabetic-retinopathyhttp://app.readspeaker.com/cgi-bin/rsent?customerid=5841&lang=en_us&readid=textArea&url=http://www.webmd.com/diabetes/closer-look-diabetic-retinopathyhttp://www.webmd.com/diabetes/closer-look-diabetic-retinopathyhttp://www.webmd.com/diabetes/closer-look-diabetic-retinopathyhttp://www.webmd.com/diabetes/closer-look-diabetic-retinopathyhttp://app.readspeaker.com/cgi-bin/rsent?customerid=5841&lang=en_us&readid=textArea&url=http://www.webmd.com/diabetes/closer-look-diabetic-retinopathyhttp://www.webmd.com/diabetes/closer-look-diabetic-retinopathy#1


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There are currently a number of biometric devices in use, machines that can identify

people by their physical characteristics. Some examples include fingerprint scanners

and devices that can recognize a particular voice, hand, or signature. The retinal scanner

is another addition to the identification tool kit.

How Retinal Scanning Works

A retinal scanner uses infrared light for mapping. As a person looks into the eyepiece, an

invisible beam of low-energy infrared light traces a circular path on the retina at the

back of the eye. The blood-filled capillaries absorb more of the infrared light than the

surrounding tissue. Because of this, there is a variation in the intensity of the reflection.

The scanner measures this reflection at 320 points along the beam path. It then assigns

an intensity grade between zero and 4,095. The resulting numbers are compressed into

an 80-byte computer code. This code can then be compared with patterns that have

already been entered into the computer's data base.

Applications

Retina scans are already in use in the Pentagon and government and corporate

organizations where people need to be identified before they can enter an area. New

concerns about security from terrorism and bank and credit card fraud have causedmany organizations to think seriously of using retina scans or other biometric means to

identify people at airports and ATM machines.

Some states require that truck and bus drivers be mapped by retinography. This

information is used by state agencies to prevent bad drivers from holding licenses in

several states to hide their driving records. A proposedand more controversialuse of

retina scans is to develop a worker registry, where everyone is scanned to make sure that

they are legal citizens of the United States, and thus eligible for employment. Critics ofthis proposal are concerned about possible invasions of privacy and violations of other

personal rights.

Advantages and Disadvantages


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Retinal scanners have several advantages over fingerprinting and voice recognition

systems. They do not require as much computer memory as a fingerprint scan, and they

are not subject to contamination from dirt or finger misplacement. Unlike voice

recognition systems, retinal scanner are not distracted by background noise or changes

in voice caused by illness.

The main disadvantage of the retinal scanner is that the person has to focus on the

scanner from about three inches away. This restriction makes the device difficult for

ATM use because a person using a cash machine rarely focuses on one area very long

and is never close enough. A new device called an iris scanner may prove more useful for

these casual transactions, since the scanning camera can be farther away and only has to

scan the pattern of the iris (colored portion) of the eye, a procedure which does not

require focusing on the camera.

Read more:http://www.discoveriesinmedicine.com/Ra-

Thy/Retinography.html#ixzz3ND7NxWqW
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