Eye Health Channel

Symptoms of Cataracts

Tue, 08 Nov 2011 17:17:22 -0800

Cataracts are more common in older people and the symptoms usually develop over time. In fact, most people do not realize they have cataracts at first because the symptoms develop so slowly.

Some symptoms of cataracts include:

• Double vision in one eye
• Blurry, cloudy, or dimming vision (increasing over time)
• Sensitivity to lights, such as the sun or headlights on other cars
• Color dullness
• A "halo" appearance around lights (especially at night)
• Regular changes in eye sight levels, causing a change in glasses prescription

Symptoms of cataracts vary from person to person, although most patients report that they feel as though they are constantly looking through a foggy or dirty window. This experience will worsen as the eye condition develops over time.

Cataracts are not painful and don't cause problems with the eye other than the symptoms listed above. Also, eye redness is usually not associated with this eye disorder.

If you are experiencing these symptoms, your doctor will need to make changes to your glasses prescriptions. In severe cases, surgery may be needed to correct the problem.

What Is Astigmatism?

Mon, 10 Oct 2011 19:43:16 -0800

Astigmatism is a very common vision problem that causes blurred and distorted vision. It is caused by a curvature defect of the eye and can affect both near and distance vision. There are two types of astigmatism - regular astigmatism and irregular astigmatism.

What Causes Astigmatism?

Fri, 11 Mar 2011 19:35:33 -0800

Astigmatism is caused by an irregular shape of the cornea or the lens inside the eye and is often genetic but may also be caused by an injury to the eye. In a normal eye, the cornea is shaped like a basketball, while a cornea affected by astigmatism is shaped like a football. There are two types of astigmatism, regular and irregular.

Regular Astigmatism
Regular astigmatism occurs when the shape of the cornea or crystalline lens is irregular.

Irregular Astigmatism
Irregular astigmatism is often caused by corneal scarring or scattering in the crystalline lens. This type of astigmatism can only be corrected with contact lenses and not with glasses.

Astigmatism Surgery

Fri, 11 Mar 2011 18:49:54 -0800

LASIK Surgery
If you have astigmatism, you may be a candidate for LASIK (laser-assisted in situ keratomileusis) surgery. Lasik is a type of refractive surgery. In people with astigmatism, it works by reshaping the misshaped cornea.

Whether LASIK will work for you depends on the type of astigmatism you have. Your opthalmologist can determine whether LASIK is right for you.

PRK Surgery
PRK (photorefractive keratectomy) is a type of laser surgery for astigmatism that is used to reshape the cornea with ultraviolet light. It is less commonly used now that LASIK is the most common type of surgery used for astigmatism.

AK Surgery
AK (astigmatic keratotomy) is a surgical procedure for astigmatism that does not use a laser. The surgeon makes incisions in the cornea in order to reshape it.

Astigmatism Contacts

Thu, 10 Mar 2011 21:20:30 -0800

Rigid Gas Permeable
Rigid gas permeable contact lenses are the most common contact lens used in correcting severe cases of astigmatism. They work by reshaping and holding the cornea in place. Unlike soft contact lenses, they can be uncomfortable because they are made of hard plastic that forces the eye to remain in shape rather than the soft lenses that movie and glide with the natural shape of the eye.

Soft Toric Lenses
Soft toric lenses are flexible lenses with special features for astigmatic eyes that normal soft lenses do not have. These lenses are much more comfortable than gas permeable lenses. Like regular soft contact lenses, soft toric lenses are available in extended wear and disposable varieties.

One issue that may occur with this type of lens is that the vision may fluctuate when the lens moves in the eye. This bothers some people and they may prefer the rigid gas permeable lenses that keep the vision steady.

Only your opthalmologist can determine which type of contact lens will work best for you. If you have a complicated case of astigmatism, you may need to try several different types of contact lens before finding the right one for your eyes.

Astigmatism Glasses
Astigmatism Treatment
Astigmatism Surgery
Astigmatism Videos

Astigmatism Glasses

Thu, 10 Feb 2011 21:28:55 -0800

Glasses are the easiest way to correct for uncomplicated astigmatism. Glasses with toric lenses are specially made to correct for the patient's corneal irregularity. When the patient also has nearsightedness or other eye problems, a single pair of glasses can be made to correct for everything at once.

Only your opthalmologist can determine which type of glasses for astigmatism will work best for you. If you have a complicated case of astigmatism, you may need to try several different types of glasses before finding the right one for your eyes.

15 Facts About Color Blindness

Sat, 29 Jan 2011 11:38:52 -0800

Color blindness is usually genetic, but can also be caused by traumatic injury or exposure to chemicals.

There are three types of color blindness - one type makes it difficult to distinguish between red and green, the second type makes it difficult to distinguish between blue and yellow, and a third type is actually complete color blindness in which the eye cannot detect any colors at all.

Red-green color blindness affects 10% of males in the United States, while only 0.5% of women are affected. 99% of all people with color blindness have red-green color blindness.

Blue-yellow color blindness is rare and affects between 1 in 15,000 and 1 in 50,000 people. Both men and women are affected equally.

Monochromacy is the name for total color blindness. It affects about 1 in 30,000 people. Unlike people with red-green or blue-yellow color "blindness," people with monochromacy do not see any color at all, only varying shades of black, white, and gray.

An English chemist named John Dalton, who was himself colorblind, published the first scientific paper on color blindness in 1798.

Color blindness may be an advantage. Colorblind capuchin monkeys are able to catch more insects per hour than non-color blind capuchins. The U.S. Army has found that colorblind people are able to spot camouflaged objects much better than non-colorblind people.

A woman who is red-green colorblind will always have sons who are red-green colorblind.

The Ishihara test, widely used to test for color blindness, was created by Shinobu Ishihara, a Japanese opthalmologist. The Ishihara test consists of 38 plates filled with colored dots that contain numbers in dots of different shades that people who are colorblind cannot see.

The difference between red, green, and yellow traffic lights can be hard to distinguish for colorblind drivers. In Bulgaria, Romania, and Turkey colorblind people are prohibited from driving.

People with color blindness usually dream in the same limited colors they see in waking life.

Colorblind people often have difficulty with foods. They have trouble telling if a piece of red meat is cooked or raw, they can't tell whether a banana is yellow or green, and they can't see any difference between a green, unripe tomato and a ripe, red one.

One theory as to why more men die of colorectal cancer than women is that more men are colorblind and are therefore unable to detect blood on the toilet paper after a bowel movement.

Goldfish are the only animal that can see infrared and ultraviolet light and they have the largest range of color vision so far discovered in any animal.

Contrary to popular belief that dogs and cats only see in shades of gray, they are not completely color blind. However, they do see a more limited range of colors than humans.

8 Ways to Treat An Eye Injury

Thu, 27 Jan 2011 13:09:00 -0800

A minor eye injury can be uncomfortable and distressing. The human eye is an amazingly fine tuned machine with many subtleties. If the injury is serious, you should seek medical treatment immediately. If you feel you have a minor injury and want to treat it at home, the following eight tips will prove useful.

Wash Your Hands
When touching your eye, make sure to use only clean hands, swabs and bandages when treating the eye. If the injury was sustained under circumstances in which infectious bacteria or fungi are likely present (such as a cat scratch), you should see a doctor immediately.

Remove the Irritant
Flushing is ideal for removing most substances. Generally, only a professional should use swabs or anasthetic in the eye.

Don't Rub!
This is especially important if you think it is possible that foreign material may still be present in the eye. A very small amount of dust or dirt could easily scratch the cornea if rubbed in through the eyelid.

Keep It Clean
The most dangerous aspect of a minor eye injury is the possibility of infection. Some bacteria and fungi can cause permanent vision impairment or even complete blindness within 1-2 days. Continue to wash your hands thoroughly as you may touch the irritated area inadvertently during the healing process.

Get Some Sleep
Rest is what a minor eye injury is likely to need most so, if possible, catch some Z's and you may awake to find the pain has passed.

Cover or Close the Eye
The cover should be loose fitting (not a patch) to minimize risk of infection. A paper cup that is carefully taped on should work. This is really the best option if you can't sleep.

Minimize Light Exposure
If it is not possible to sleep or cover the eye, you might lower the light levels in order to give the eye a break and reduce squinting. Extreme light sensitivity that does not subside may be a sign that the scratch is too serious to forgo a doctor's treatment.

Be Safe, Not Sorry!
If you are experiencing swelling, puffiness, extreme redness, bleeding, or if you think the cornea may actually be scratched, loosely cover the injured eye and seek medical attention immediately. If there are chemicals involved (anything abrasive, acid, alkaline, even chalk dust) rinse the eye for fifteen minutes and get to a doctor. The eye is one of the most complex and delicate organs in the body so don't take chances with your vision.

Astigmatism Treatment

Tue, 11 Jan 2011 19:11:58 -0800

Glasses
Glasses can be made to correct almost every type of astigmatism. Visit our astigmatism glasses page for more information.

Contact Lenses
There are two types of contact lenses available for people with astigmatism - rigid gas permeable and soft toric lenses. It often takes a bit of trial and error to find the right kind of soft lenses for a person's astigmatism. Visit our page on astigmatism contacts for more details about the types of contacts that are available for astigmatism.

Surgery
Surgical options for astigmatism include laser surgery such as LASIK (laser-assisted in situ keratomileusis)and PRK (photorefractive keratectomy) as well as non-laser surgery such as AK (astigmatic keratotomy). To learn more about the different types of surgeries, visit our astigmatism surgery page.

Astigmatism Symptoms

Mon, 10 Jan 2011 21:47:52 -0800

The symptoms of astigmatism may include:

Blurred vision
Distorted vision
Eye pain
Headaches

If you are experiencing any of these symptoms, visit your eye doctor so he or she can properly diagnose you and help you to correct the problem.

Eyelash Thickening Drug Latisse May Be Approved

Tue, 09 Dec 2008 01:54:58 -0800

An FDA advisory panel has given the thumbs up to a new drug, Latisse, that helps people grow fuller, darker eyelashes. Latisse was created after its maker, Allergan, Inc, discovered that eyelash growth was a side effect of its glaucoma drug, Lumigan. They decided to do a study on the drug's effect on eyelashes.

In that study, 137 people used Latisse and 141 people used a placebo solution for 16 weeks. The result: Thicker, longer, darker eyelashes were more common by the end of the study in the Latisse group. And people in the Latisse group reported more satisfaction with their lashes than people who used the placebo.

Unlike Lumigan, Latisse is not placed directly in the eye and may therefore not have the same side effects. Side effects of Lumigan include possible eye redness, darkening of the eyelid skin, and darkening of the iris.

If the FDA takes the panel's recommendation and approves the drug, it could be available by prescription in 2009.

Contact Lens Cases Often Contaminated

Fri, 28 Nov 2008 13:16:48 -0800

A new study has found that contact lens cases are often contaminated with pathogens that may cause serious eye infection.

Pathogens were found in all the types of storage solutions examined in the study, and some of the solutions tested positive for pathogens every time they were tested. These pathogens can cause keratitis, an often painful inflammation of the cornea. Complications from keratitis can lead to vision loss.

Researchers recommend replacing contact lens cases on a regular basis and making sure to maintain good contact lens cleaning practices.