Categories
Ailmemts & Remedies

Astigmatism

Definition:
Astigmatism is a common, mild and generally easily treatable imperfection in the curvature of your eye. The condition can cause blurred vision.

Astigmatism occurs when the front part of the eye, the cornea, is not a regular symmetrical spherical shape. Instead, its shape is rather like that of the back of a spoon – longer in one direction than another. Because the cornea is an irregular shape, the eye can’t focus light passing through it sharply on to the back of the eye or retina. So vision is blurred at all distances.
CLICK & SEE THE PICTURES

Astigmatism is often present at birth and may occur in combination with nearsightedness or farsightedness. Often it’s not pronounced enough to require corrective action. When it is, your treatment options include corrective lenses and surgery.

Many people have some degree of astigmatism. In fact, it is rare to find a perfectly formed eye. Astigmatism appears to run in families and is often present from birth. If you have astigmatism, chances are good your children will have it also. It may worsen slowly over time but may remain fairly stable throughout life. Astigmatism often occurs with other vision conditions such as nearsightedness (myopia) and farsightedness (hyperopia.)

Symptoms:
Signs and symptoms of astigmatism may include:

*Blurred or distorted vision
*Headaches
*Eye strain
*Fatigue
*Blurred vision at certain distances

The most common symptom of astigmatism is blurred vision. Some people describe it as double vision but in only one eye. As a result of trying to focus on near or distant objects, a patient may develop eyestrain, squinting and headaches. Note the diagram at right – a person WITHOUT astigmatism would see all the radial lines as perfectly sharp and with the same contrast. The diagram  below illustrates how some lines might appear clearer than others to a person with astigmatism.

Children with astigmatism may be too young to notice or describe astigmatism. They may frown, squint, or pull objects close in an effort to get a clearer picture. They may also tilt or turn their head. This extra effort can lead to eyestrain, fatigue or reduced reading efficiency.

Causes:
As the eye develops in the womb, several factors determine the shape of it, including inherited genetic factors and environment. It would seem that these factors can lead to an irregular curvature of the cornea, although the exact cause isn’t known.

Your eye has two parts that focus images — the cornea and the lens. In a perfectly shaped eye, each of these focusing elements has a perfectly smooth curvature, like the surface of a smooth ball. A cornea or lens with such a surface curvature bends (refracts) all incoming light the same way and makes a sharply focused image on the back of your eye (retina).

However, if your cornea or lens isn’t evenly and smoothly curved, the light rays aren’t refracted properly. This causes a refractive error. Astigmatism is one type of refractive error. In astigmatism, your cornea or lens is curved more steeply in one direction than in another. When the cornea has a distorted shape, you have corneal astigmatism. When the lens is distorted, you have lenticular astigmatism. Either type of astigmatism can cause blurred vision. Blurred vision may occur more in one direction — either horizontally, vertically or diagonally.

Astigmatism may occur in combination with other refractive errors, which include:

*Nearsightedness (myopia).
This occurs when your cornea is curved too much or your eye is longer than normal. Instead of being focused precisely on your retina, light is focused in front of your retina, resulting in a blurry appearance for distant objects.
*Farsightedness (hyperopia). This occurs when your cornea is curved too little or your eye is shorter than normal. The effect is the opposite of nearsightedness. When your eye is in a relaxed state, light is focused behind the back of your eye, making nearby objects blurry.

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Astigmatism may be present from birth, or it may develop after an eye injury, disease or surgery. Astigmatism isn’t caused or made worse by reading in poor light, sitting too close to the television or squinting.

Test & Diagnosis :

The Simple Astigmatism test :
1.If you have contacts or glasses, wear them.
2.Sit about 14 inches away from your computer screen.
3.Cover one eye.
4.Note how the lines and squares appear (for example, wavy or blurred).
5.Test the other eye in the same manner.

To a normal eye, the lines will appear sharply focused and equally dark. If some sets of lines appear sharply focused and dark while others are blurred and less dark, you may have astigmatism. Regardless of your result, see your eye doctor on a regular basis for a complete eye exam.

To diagnose astigmatism, your eye doctor may:

*Measure reflected light. By measuring light reflected from the surface of your cornea, a device known as a keratometer quantifies the amount and orientation of corneal astigmatism.
*Measure the curvature of your cornea. Using light to project rings on to your cornea, a device called a keratoscope measures the amount of curvature to your cornea’s surface and can confirm the presence of astigmatism. Observation through the keratoscope of the reflection of light from your cornea and inspection of the shape and spacing of the rings provide information about the degree of astigmatism.

To measure the change in corneal surface curvature, a process called corneal topography is used. Corneal topography uses a videokeratoscope, which is a keratoscope fitted with a video camera.

Treatment:
The goal of treating astigmatism is to address the uneven curvature that’s causing your blurred vision. Treatments include wearing corrective lenses and undergoing refractive surgery.

Corrective lenses
:
Wearing corrective lenses treats astigmatism by counteracting the uneven curvature of your cornea. Types of corrective lenses are:

*Eyeglasses. Eyeglasses can be made with special lenses that help compensate for the uneven shape of your eye. In addition to correcting astigmatism, eyeglasses can also correct for other refractive errors, such as nearsightedness or farsightedness.

*Contact lenses
. Like eyeglasses, contact lenses can correct astigmatism. A wide variety of contact lenses are available — hard, soft, extended wear, disposable, rigid gas permeable and bifocal. Ask your eye doctor about the pros and cons of each and which contact lenses might be best for you.

Contact lenses are also used in a procedure called orthokeratology, or Ortho-K. In orthokeratology, you wear rigid contact lenses for several hours a day until the curvature of your eye improves. Then, you wear the lenses less frequently to maintain the new shape. If you discontinue this treatment, your eyes return to their former shape. Wearing contact lenses for extended periods of time increases the risk of infection in the eye.

Refractive surgery;
This astigmatism treatment method corrects the problem by reshaping the surface of your eye. Refractive surgery methods include:

*LASIK surgery.
Laser-assisted in-situ keratomileusis (LASIK) is a procedure in which a doctor uses an instrument called a keratome to make a thin, circular hinged cut into your cornea. Alternatively, this same cut can be made with a special cutting laser. The surgeon lifts the flap and then uses an excimer laser to sculpt the shape of the cornea under the flap. An excimer laser differs from other lasers in that it doesn’t produce heat.

*Photorefractive keratectomy (PRK).
In PRK, your surgeon removes the outer protective layer of the cornea before using an excimer laser to change the curvature of the cornea.

*Laser-assisted subepithelial keratomileusis (LASEK).
In this procedure, a much thinner layer of cornea is folded back, which makes your eye less vulnerable to damage should an injury occur. LASEK may be a better option if you have a thin cornea or if you’re at high risk of an eye injury at work or from playing sports.

Radial keratotomy is a procedure that was used in the past to correct astigmatism. However, it’s not commonly performed anymore.

Conclusion:
If you experience a distortion or blurring of images at all distances — nearby as well as far — you may have astigmatism. Even if your vision is fairly sharp, headache, fatigue, squinting and eye discomfort or irritation may indicate a slight degree of astigmatism. A thorough eye examination, including tests of near vision, distant vision and vision clarity, can determine if astigmatism is present. Your eye doctor can answer any questions you may have about the various methods for correcting astigmatism and other vision problems.

Disclaimer: This information is not meant to be a substitute for professional medical advise or help. It is always best to consult with a Physician about serious health concerns. This information is in no way intended to diagnose or prescribe remedies.This is purely for educational purpose.
Resources:
http://www.bbc.co.uk/health/physical_health/conditions/astigmatism2.shtml
http://www.dcareaeyecare.com/astigmatism_article.html
http://www.mayoclinic.com/health/astigmatism/DS00230
http://www.lasersurgeryforeyes.com/astigmatism.html#Symptoms
http://www.webmd.com/eye-health/understanding-astigmatism-basics
http://www.jnjvision.com/thinking-whocanwear-test.htm

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News on Health & Science

Synthetic Corneas Prove Successful

The collagen-based implants could be an alternative to cadaver corneas. A preliminary test shows that they restored vision as effectively as the latter and did not require anti-rejection drugs.
……………..

An experimental synthetic cornea implanted in 10 patients may be a potential alternative to cadaver corneas for curing vision loss due to corneal inflammation and scarring, researchers said .

Eye surgeons currently use primarily cadaver corneas for transplants, but that requires the use of anti-rejection drugs and presents a risk of infection. Plastic corneas can also be used, but they present other problems and are generally tried only when tissue transplants have failed.

The new artificial corneas use collagen produced in yeast as a scaffolding that allows cells from the recipient to grow into the graft so that it mimics the original tissue. The two-year preliminary test showed that the biosynthetic corneas restored vision as effectively as cadaver corneas, did not require anti-rejection drugs and allowed normal tears to form.

“This is a huge breakthrough,” said Dr. Francis W. Price Jr., founder and president of the board of the Cornea Research Foundation, who was not involved in the research. “It still has to go through additional studies … but it shows a lot of promise.”

An estimated 5 million people worldwide suffer corneal damage from trachoma, an eye infection caused by the bacterium Chlamydia trachomatis, and another 1.5 million to 2 million people develop it as a result of ulceration and trauma. In the United States, about 42,000 cadaver cornea transplants are performed each year and another 10,000 corneas are exported to other countries, according to Marianne O’Connor Price, executive director of the Cornea Research Foundation.

“The U.S. is very fortunate that everybody who needs a transplant here is able to get one, but there is definitely a big shortage around the world,” she said. “Even people here could benefit if there was a synthetic cornea that eliminated the chance of rejection.”

The new study, reported Wednesday in the journal Science Translational Medicine, used biosynthetic collagen produced by FibroGen Inc. of San Francisco. A team headed by Dr. May Griffith of the Ottawa Hospital Research Institute in Canada molded the collagen into an artificial cornea and demonstrated that it worked in animals.

Dr. Per Fagerholm of Linkoping University in Sweden then implanted the corneas in one eye of each of 10 Swedish patients with central corneal scarring. The researchers found that, after two years, no complications developed and, with the use of contact lenses, vision was as good as with cadaver transplants. Contact lenses are normally used with the latter as well.

The study is the first to show that an artificially fabricated cornea “can integrate into the human eye and stimulate regeneration,” Griffith said.

Griffith said her team was now building a clean room to manufacture more of the corneas and that she hoped to begin larger clinical trials after the first of the year with about 20 to 25 patients.
When implanted with contact lenses that they previously couldn’t tolerate, patients saw as well as a similar group of patients who had received standard corneal transplants.

The study is the first to show that an artificially fabricated cornea “can integrate into the human eye and stimulate regeneration,” Griffith said.

Griffith said her team is building a clean room to manufacture more corneas and hopes to begin larger clinical trials with 20 to 25 patients.

Researchers also are working to create stem-cell treatments that could spur corneal growth.

You may click to see this as well and Synthetic cornea offers hope to thousands

Resource :

Los Angeles Times

The Seattle Times

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Categories
Diagnonistic Test

Tonometry

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Alternative Names:Intraocular pressure (IOP) measurement; Glaucoma test
Definition:
Tonometry is the measurement of tension or pressure  in your eyeball. High pressure inside the eye is caused by a disease called glaucoma, which can damage your vision if it is not treated. It is recommended that all adults over age 40 have their eye pressures measured every three to five years to check for glaucoma.Because People over age 40, especially African-Americans, are at the highest risk for developing glaucoma. Regular eye exams can help detect glaucoma early, when it can usually be treated.

A tonometer is an instrument for measuring tension or pressure ……..CLICK & SEE

In ophthalmology, tonometry is the procedure eye care professionals perform to determine the intraocular pressure (IOP), the fluid pressure inside the eye. It is an important test in the evaluation of ocular conditions such as glaucoma as well as conditions such as phthisis bulbi, and iritis. Most tonometers are calibrated to measure pressure in mmHg.
How do you prepare for the test?
Remove any contact lenses before the examination.The dye can permanently stain contact lenses.  Inform the health care provider if you have corneal ulcers and infections, an eye infection, if you are taking any drugs, or if you have a history of glaucoma in your family or other type of eye problem.
What happens when the test is performed and how it is done?
The pressure inside your eye is always measured from the outside. In most cases, if you are at an eye clinic, the pressure can even be measured without anything actually touching your eye. The eye doctor has you look up close at an instrument that blows a small puff of air onto your eye. It then uses a special sensor (like a tiny radar detector) to detect the amount of indentation that the air puff causes on the surface of the eye. This indentation is normal and lasts for only a fraction of a second.

Sometimes patients need to have their eye pressure measured but they are not in an eye clinic with this type of machine (for example, some patients need to be checked for glaucoma in an emergency room). In this case, the pressure can be measured with an instrument resembling a pen. One end of the instrument is placed on the surface of the eyeball. This feels like having a contact lens put in your eye.

There are several methods of testing for glaucoma.

The applanation method measures the force required to flatten a certain area of the cornea. A fine strip of paper stained with orange dye is touched to the side of the eye. The dye stains the front of the eye to help with the examination, then rinses out with tears. An anesthetic drop is also placed in the eye.

The slit-lamp is placed in front of you and you rest your chin and forehead on a support that keeps your head steady. The lamp is moved forward until the tonometer touches the cornea. The light is usually a blue circle. The health care provider looks through the eyepiece on the lamp and adjusts the tension on the tonometer. There is no discomfort associated with the test.

A slightly different method of applanation uses an object similar to pencil. Again, you are given numbing eye drops to prevent any discomfort. The device touches the outside of the eye and instantly records eye pressure.

The last method is the noncontact method (air puff). In this method, your chin rests on a padded stand. You stare straight into the examining device. The eye doctor shines a bright light into your eye to properly line up the instrument, and then delivers a brief puff of air at your eye. The machine measures eye pressure by looking at how the light reflections change as the air hits the eye.

Must you do anything special after the test is over?
Nothing.
How the Test Will Feel?
If numbing eye drops were used, you should not have any pain. In the noncontact method, you may feel mild pressure on your eye.

What risks are there from the test?
The test might make you feel like blinking, but it does not cause any pain. There are no risks from this test.If the applanation method is used, there is a small chance the cornea may be scratched (corneal abrasion). This will normally heal itself within a few days.

How long is it before the result of the test is known?
You can know the result of the test right away.

Results:

Normal Results

The eye pressure is within the normal range.

Normal eye pressure range is 10 – 21 mm Hg.

What Abnormal Results Mean?

Glaucoma may be detected.

Additional conditions under which the test may be performed:

Hyphema
*Trauma to the eye or head
*Before and after eye surgery

Resources:
http://en.wikipedia.org/wiki/Tonometry
https://www.health.harvard.edu/diagnostic-tests/tonometry.htm
http://www.nlm.nih.gov/medlineplus/ency/article/003447.htm

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Categories
Ailmemts & Remedies

Eye Injuries

 

a small piece of iron has lodged near the marg...Image via Wikipedia

It’s common for a speck of dirt to get blown into your eye, for soap to wash into your eye, or for you to accidentally bump your eye. For these types of minor eye injuries, home treatment is usually all that is needed.

click to see the pictures

Some sports and recreational activities increase the risk of eye injuries.
*Very high-risk sports include boxing, wrestling, and martial arts.

*High-risk sports include baseball, football, tennis, fencing, and squash.

*Low-risk sports include swimming and gymnastics (no body contact or use of a ball, bat, or racquet).

Blows to the eye:-
Direct blows to the eye can damage the skin and other tissues around the eye, the eyeball, or the bones of the eye socket. Blows to the eye often cause bruising around the eye (black eye) or cuts to the eyelid. If a blow to the eye or a cut to the eyelid occurred during an accident, be sure to check for injuries to the eyeball itself and for other injuries, especially to the head or face. Concern about an eye injury may cause you to miss other injuries that need attention.

Burns to the eye:-
Burns to the eye may be caused by chemicals, fumes, hot air or steam, sunlight, tanning lamps, electric hair curlers or dryers, or welding equipment. Bursts of flames or flash fires from stoves or explosives can also burn the face and eyes.

*Chemical burns can occur if a solid chemical, liquid chemical, or chemical fumes get into the eye. Many substances will not cause damage if they are flushed out of the eye quickly. Acids and alkali substances can damage the eye. It may take 24 hours after the burn to determine the seriousness of an eye burn. Chemical fumes and vapors can also irritate the eyes.

*Bright sunlight (especially when the sun is reflecting off snow or water) can burn your eyes if you do not wear sunglasses that filter out ultraviolet (UV) light. Eyes that are not protected by a mask can be burned by exposure to the high-intensity light of a welder’s equipment (torch or arc). The eyes also may be injured by other bright lights, such as from tanning booths or sunlamps.

For more information, you may click to see :-> Burns to the Eye.

Foreign objects in the eye:-
A foreign particle  in the eye, such as dirt, an eyelash, a contact lens, or makeup, can cause eye symptoms.

*Objects may scratch the surface of the eye (cornea) or become stuck on the eye. If the cornea is scratched, it can be hard to tell whether the object has been removed, because a scratched cornea may feel painful and as though something is still in the eye. Most corneal scratches are minor and heal on their own in 1 or 2 days.

*Small or sharp objects traveling at high speeds can cause serious injury to many parts of the eyeball. Objects flying from a lawn mower, grinding wheel, or any tool may strike the eye and possibly puncture the eyeball. Injury may cause bleeding between the iris and cornea (hyphema), a change in the size or shape of the pupil, or damage to the structures inside the eyeball. These objects may be deep in the eye and may require medical treatment.

In the case of a car air bag inflating, all three types of eye injuries can occur. The force of impact can cause a blow to the eye, foreign objects may enter the eye, and chemicals in the air bag can burn the eye.
Eye injuries can be prevented by using protective eyewear. Wear safety glasses, goggles, or face shields when working with power tools or chemicals or doing any activity that might cause an object or substance to get into your eyes. Some professions, such as health care and construction, may require workers to use protective eyewear to reduce the risk of foreign objects or substances or body fluids getting in the eyes.

After an eye injury, you need to watch for vision changes and symptoms of an infection. Most minor eye injuries can be treated at home. You may click to See :->the Home Treatment.

EMERGENCIES:-
Call emergency services immediately!

Do you have any of the following symptoms that require emergency treatment? Call 911 or other emergency services immediately.

*An object has punctured and penetrated the eye. Note: Do not bandage or put any pressure on the eye. If an object has penetrated the eyeball, hold the object in place to prevent further movement and injury to the eye.
*An eyeball is bulging out of its socket or looks abnormal after an injury.
*Sudden partial or complete vision loss has occurred in one or both eyes. Note: Treatment is needed within 90 minutes to save vision.


*Severe pain continues after 30 minutes of flushing a chemical from the eye.
*Normal vision is limited to one functional eye.

PREVENTION:-

The following tips may help prevent eye injuries.

*Wear safety glasses, goggles, or face shields when you hammer nails or metal, work with power tools or chemicals, or do any activity that might cause a burn to your eyes. If you work with hazardous chemicals that could splash into your eyes, know how to flush chemicals out, and know the location of the nearest shower or sink.

*If you are welding or near someone else who is welding, wear a mask or goggles designed for welding.

*Wear protective eyewear during sports such as hockey, racquetball, or paintball that involve the risk of a blow to the eye. Baseball is the most common sport to cause eye injuries. Fishhook injuries are another common cause of eye injuries.
Protective eyewear can prevent sports-related eye injuries more than 90% of the time. An eye examination may be helpful in determining what type of protective eyewear is needed.

*Injuries from ultraviolet (UV) light can be prevented by wearing sunglasses that block ultraviolet (UV) rays and by wearing broad-brimmed hats. Be aware that the eye can be injured from sun glare while boating, sunbathing, or skiing. Use eye protection while you are under tanning lamps or using tanning booths. Laser pointers have not been shown to cause eye injury.

*Wear your seat belt when in a motor vehicle. Use child car seats.

Prevention tips for children:-
Eye injuries are common in children, and many can be prevented. Most eye injuries happen in older children. They happen more often in boys than in girls. Toys—from crayons to toy guns—are a major source of injury, so check all toys for sharp or pointed parts. Household items, such as elastic cords, can also strike the eye and cause injury.

Teach your children about eye safety. :-

*Be a good role model—always wear proper eye protection.

*Get protective eyewear for your children and help them use it properly.

*Teach children that flying toys should never be pointed at another person.

*Teach children how to carry sharp or pointed objects properly.

*Teach children that any kind of missile, projectile, or BB gun is not a toy.

*Use safety measures near fires and explosives, such as campfires and fireworks.

Any eye injury that appears unusual for a child’s age should be evaluated as possible child abuse.

Sources: MSN Health & Fitness

 

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