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Archive for the ‘Eye Anatomy’ Category

Can You Change the Color of Your Iris?

Tuesday, November 15th, 2011

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LASIK and Corneal Scars

Thursday, September 29th, 2011

A corneal scar is an injury to your eye’s cornea. Having a corneal scar doesn’t necessarily disqualify you from LASIK eye surgery, but certain types of scars can have a negative effect on the results of surgery. You ophthalmologist should carefully examine your corneal scar to consider the following factors:

The depth of the scar – If your scar is superficial, it is possible to remove it during LASIK surgery. A deeper scar can be reduced and improved with a different laser treatment (such as PRK), but it still might not be completely eliminated.
The location of the scar – Unless your scar is close to the center of your eye, you are probably still a candidate for LASIK. However, if it is too close to your visual axis and has an effect on your vision, your ophthalmologist may recommend an alternative laser treatment.
The cause of the scar – If the scar was the result of an infection, the exact type of infection may affect your LASIK candidacy. For example, if viral keratitis caused your scar, there is a slight risk that LASIK surgery would re-activate the virus.

LASIK surgery should only be performed on patients who are ideal candidates. In some situations, corneal scars can be reduced or eliminated by Laser Vision Correction. But if your ophthalmologist believes your corneal scar would pose an undue risk, he or she can work with you to find an alternative solution.

If you would like more information about LASIK and scarred eyes, contact an experienced LASIK eye surgeon in your area today.

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Which Eye is My Dominant Eye?

Monday, August 29th, 2011

Human beings have binocular vision, meaning each of our eyes sees a slightly different scene. We don’t notice this, since both images our eyes see merge into one, giving us depth perception. But in reality, whenever you look at an object, one of your eyes will look directly at it, while the other sees it at a slight angle. The eye that looks directly at whatever you are focusing on is called your dominant eye.

In order to determine which of your eyes is dominant, you can perform a quick and easy experiment called the Dolman method:

First, take a piece of paper or cardboard and cut a square or circle in its center. Make the square/circle about an inch wide.
Hold the paper at arm’s length in front of you with both hands.
Look through the hole at any nearby object that isn’t moving.
As you focus on that object, draw the paper gradually closer to you until it’s touching your face.

You will discover that the hole is in front of your dominant eye, which is the one that has been focusing on the object all along. Your other eye has been looking at it from a slightly different angle.

If you would like to speak with a qualified eye doctor near you, please visit our ophthalmologist directory today.

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Floaters 101: What’s Normal and What’s Not

Tuesday, July 19th, 2011

What Are Floaters?

Most everyone experiences floaters at one time or another. If you’ve ever been staring off into space and seen a dot or line drifting in front of your eyes, you’ve had a floater. Floaters are usually small pieces of debris in the eye’s vitreous humor, the gel-like substance between the lens and the retina that helps give your eye its shape.

Most of the time, floaters are not a problem. You will primarily notice them if you are staring at a blank, light surface like a wall or countertop, but they should not be bothersome or hinder your vision during everyday activities.

Are There More Serious Problems Associated with Floaters?

If you start to see many floaters accompanied by flashes of light and vision loss, you should schedule an appointment with your eye doctor. These are signs of retinal detachment, where the retina becomes torn or disconnected in the eye. If left untreated, a detached retina leads to loss of blood flow to the eye and permanent blindness.

Another problem associated with floaters is called Degenerative Vitreous Syndrome or DVS. As the eye ages, the vitreous humor begins to break down, liquefying and pulling away from the retina. Collagen fibers in the vitreous humor begin to clump together and become floaters.

This is a natural part of the aging process. However, the clumps may become so numerous that they begin to block large portions of the retina, causing problems with driving, reading, and other daily activities. Surgery is one treatment option that can remove the floaters, but it is often accompanied by many risks.

If you have more questions about floaters and treatment options, please contact an experienced ophthalmologist in your area who can answer your questions during your free consultation.

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Retinal Reattachment Restores Vision after 55 Years

Thursday, June 30th, 2011

More than five decades after his retina became detached when he was hit in the right eye with a stone, a man had his vision surgically restored in what is thought to be a medical first.

The patient was 8 when he was struck with a rock in the right eye, detaching his retina. Blind in that eye, the man went to the New York Eye and Ear Infirmary at age 63, complaining of pain in his right eye.

Doctors found bleeding, swelling and glaucoma. After treatment with monoclonal antibody therapy, the patient reported being able to detect light sources with his right eye. Encouraged, doctors recommended pursuing surgery to reattach the retina.

When the retina is detached from its blood supply, retinal cells can begin to die and impair vision. If a detached retina is not treated quickly, the retina can become permanently damaged and lead to blindness; when the retina is detached for an extended period, it’s typically impossible to restore sight with reattachment.

However, despite a 55-year gap between the incident that caused his vision loss and retinal reattachment surgery, the man’s sight was restored following the procedure. Doctors said restoring vision after such a lengthy period of retinal detachment was a first.

Although the patient required revision surgery a year later because scars in his eye were forcing the retina to separate again, the follow-up surgery was also successful. Doctors hope this bodes well for future research into restoring damaged retinas and retinal cells.

“This is not only a great result for our patient but has implications for restoring eyesight in other patients, especially in the context of stem cell research into retinal progenitor cells, which may be able to be transplanted into diseased retinas to restore vision,” said Dr. Olusa Olawoye in a June Journal of Medical Case Reports article.
If you would like to learn more about retinal detachment, please contact an ophthalmologist near you.

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Single Donor Cornea Can Help Two Patients

Wednesday, February 16th, 2011

Doctors in Germany, led by Ludwig M. Heindl, M.D. of Friedrich-Alexander University Erlangen-Nurnberg, have published a study in this month’s issue of Ophthalmology demonstrating that a single donor cornea can help two different recipients.

Not all cornea transplant recipients need the full thickness of the donor cornea, of which Dr. Heindl and colleagues took advantage. They split the donor corneas into two layers—the anterior lamella and the endothelium-Descemet’s membrane.

The first layer, the anterior lamella was then transplanted onto the eyes of a patient suffering from keratoconus. This type of corneal transplant is known as a deep anterior lamellar keratoplasty, or DALK.

Next, the second layer was transplanted into a different patient who had Fuchs’ endothelial dystrophy. This surgery is called Descemet’s stripping endothelial keratoplasty (DSEK).

This resourceful approach may have very positive implications for the future of corneal transplant surgery, allowing patients with different eye diseases and conditions to receive separate transplants from the same cornea. This should hopefully reduce the wait time for donor corneas and reduce the overall cost of cornea transplantation.

To learn more about corneal transplants or to get treatment for a cornea condition that affects your vision, please contact a local ophthalmologist today and set up a consultation.

Posted in Corneal Transplant, Diseases and Conditions, Eye Anatomy, Eye Surgery, Lamellar Keratoplasty | Comments Off

Common Eye Problems – Refractive Errors

Friday, January 7th, 2011

Refractive errors are the leading cause of vision problems in the United States. It is estimated that over 150 million Americans wear eyeglasses or contact lenses to correct refractive errors. The three most common eye problems are nearsightedness, farsightedness and astigmatism.

Symptoms of Nearsightedness

Myopia, or nearsightedness, allows you to clearly see objects that are close but results in blurred images of objects that are father away. Most forms of myopia do not develop in children until about age five to seven, the greatest changes occurring between ages six and twelve. You should consider having an eye exam if you or your child has any of the following symptoms:

· Squinting

· Eyestrain

· Headaches (uncommon)

Causes of Farsightedness

Hyperopia, or farsightedness, enables you to see objects at a distance but not close up. Reading, writing and watching television can be difficult if you suffer from hyperopia, as your eyes may feel tired or sore. Depending on the degree of your farsightedness and your age, you may only need reading glasses. Hyperopia can be caused by:

· Genetics (like myopia)

· Aging

· Eye tumors or diseases such as retinopathy (in rare cases)

Astigmatism Correction

Astigmatism means your corneas are in the shape of an oval instead of the normal round shape. This leads to a distortion and blurring in your vision. Astigmatism is the most common refractive error and is often accompanied by nearsightedness or farsightedness. Astigmatism can be corrected with

· Eyeglasses or contact lenses

· LASIK – surgical procedure that uses a cold-beam laser to reshape your cornea

· PRK – refractive surgery used to treat patients with large pupils or very thin corneas

· LASEK – surgical procedure used to treat patients with too thin or flat corneas that can’t be treated using tradition refractive surgical techniques.

· Implantable lenses – replaces the eye’s natural lens

If you notice symptoms of any refractive errors like those listed above, please use our Eye Doctor Directory today to schedule appointment with an optometrist or ophthalmologist in your area.

Posted in Diseases and Conditions, Eye Anatomy, Eye Surgery, LASIK, Laser Vision Correction, Refractive Errors, Uncategorized | Comments Off

Anorexia Nervosa Linked to Eye Damage

Friday, November 19th, 2010

In the past few decades, medical research has linked Anorexia Nervosa (AN) to various health problems, which are usually connected to nutritional deficiencies common among anorexic individuals. New research published last month in the British Journal of Ophthalmology has added another item to the already long list of medical issues associated with AN: eye damage.

The researchers, led by Marilita M. Moschos, MD of Greece’s University of Athens Medical School, compared 13 adult females with Anorexia Nervosa whose visual acuity, color vision, and central vision were not noticeably affected by AN to 20 healthy females in a control group. Even though the AN patients did not suffer vision loss, the study found significant thinning of the macula and the retinal nerve fiber layer (RNFL) in the patients with Anorexia. The subjects with AN also showed decreased levels of dopamine, a neurotransmitter crucial to visual processing.

The macula is a small area of the retina with a high concentration of cones, high-acuity light receptors, and pigments that protect the eye from damaging blue and ultraviolet rays. The RNFL is a layer of nerves that relay signals from across the retina to the optic nerve, which then carries the information to the brain. The thinning of these structures found in anorexic patients by this study, along with decreased dopamine activity, suggests that even when vision loss is not yet present, Anorexia Nervosa does cause damage to the eye that could increase the risk of future visual problems such as macular degeneration.

To learn more about eye diseases and conditions and how they are treated, please use our directory to find a qualified ophthalmologist in your area.

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Researchers Discover Myopia Gene

Wednesday, October 20th, 2010

A large research collaboration including scientists from Duke University Medical Center, Duke-National University of Singapore Graduate Medical School, National University of Singapore and Kings College in London has produced an important breakthrough in the genetics of eye diseases and conditions. Published in Nature Genetics last month, the research identifies a specific gene strongly linked to myopia in Caucasians.

The gene they identified is close to the RASGRF1 gene, known to be important to the function of the retina and in forming visual memories. Their findings are based on corroborating evidence from a population of more than 13 thousand people. The researchers also discovered a gene called CTNDD2 linked to myopia among Chinese and Japanese populations.

Potential for Gene Therapy

Building on these findings, the researchers believe myopia may be an excellent target for future gene therapy, which attempts to eliminate symptoms of genetic defects by repairing the genetic code itself.

While gene therapy is definitely years away, eye problems such as myopia are prime targets for gene therapy because the eye is a small, mostly self-contained organ. This would reduce the risk of gene therapy treatment causing unpredicted, adverse side effects when administered to the entire body.

For more information on current myopia treatments with laser vision correction and LASIK surgery, please visit eyes.com today or find a qualified ophthalmologist in your area.

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New Artificial Cornea May Be Viable Alternative to Corneal Transplants

Wednesday, August 25th, 2010

Washington – Scientists have developed a new type of artificial cornea by inserting a tiny amount of collagen into the eye in order to spur natural corneal cell regrowth. Initial reports indicate that the procedure has successfully restored vision in many of the trial patients.

The first wave of the study was conducted in Sweden. The sample size was very small – only 10 people. Therefore, additional studies evaluating a larger sample size will be required to conclusively determine the effectiveness of the procedure. If successful, this new artificial cornea may become a viable alternative to corneal transplants. In many parts of the world, there is a shortage of donated corneas, necessitating an alternative to meet this demand.

The cornea is a film-like covering of the eye’s surface that is responsible for focusing light on the retina. It is a fragile structure that is easily damaged by injury or infection. Approximately 42,000 people undergo corneal transplants in the United States each year. However, in many other countries, the demand for donor corneas far outweighs the supply.

Researchers are also working on several other alternative treatments such as plastic-like artificial corneas and stem cell treatments which may improve corneal growth. The current treatment being evaluated is considered a bioartificial cornea since it uses the same natural substances found in your cornea (collagen) to promote healing.

To create the bioartificial cornea, researchers molded human collagen grown in yeast into the shape of a contact lens in order to mimic the shape of a natural cornea. The damaged corneal tissue was then removed from patients’ eyes and the bioartificial cornea was implanted in its place. Corneal cells began growing in the collagen, tear production normalized, and corneal nerves began to regrow. None of the patients rejected the artificial cornea; rejection is a common risk with corneal transplants.

After two years, six of the ten patients experienced significantly improved vision with glasses and two patients experienced similar vision to before the procedure.

It is important to note that this technology currently only addresses upper layer corneal problems which comprise approximately 10% of corneal transplant cases. Moving forward, researchers will attempt to develop the technology to address full-thickness corneal damage which impacts the endothelial cells in the lower layer of the cornea.

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