New Eye Imaging Techniques Are On the Horizon

ScienceDaily (May 7, 2012) - The same technology used by astronomers to obtain clear views of distant stars is now being used by optometrists to perform incredibly detailed examinations of the living Eye.

An update on new developments in ocular imaging techniques -- and how they may affect clinical vision care in the not-too-distant future -- is presented in an article titled "Adaptive Optics Scanning Laser Ophthalmoscope-based Microperimetry" published in a special May issue of Optometry and Vision Science, official journal of the American Academy of Optometry.
Cutting-edge techniques now allow researchers to visualize the fine structure of the Eye in a way that was "not conceivable 20 years ago," according to a guest editorial by Scott Read OD PhD FAAO (Candidate) and colleagues. "As these advanced imaging methods continue to develop, the potential for imaging ocular structures down to the cellular level in everyday clinical practice has become a reality -- and the potential to improve patient care is truly stunning," Dr Read and coauthors add.
New Techniques Provide Cellular-Level Images of the Living Eye The special issue presents 30 reports on the latest, most advanced techniques for imaging and measurement of various Eye structures: the retina and optic nerve, lens and ciliary body, and the anterior Eye. Written by leading researchers and clinicians, the contributions provide a fascinating look at these remarkable new technologies, with a glimpse of their likely extensions into clinical practice.
As just one example, William S. Tuten, OD, MS, and colleagues of the University of California, Berkeley, report on the development and use of an "adaptive optics scanning laser ophthalmoscope." Adaptive optics refers to the use of advanced techniques to correct for optical aberrations through any transparent media. Originally developed for use in telescopes to correct for the distorting effects of the atmosphere, adaptive optics is now being applied to evaluating the structure and function of the human eye.
Dr. Tuten and colleagues have applied adaptive optics to perimetry -- also known as visual field testing -- on the microscopic scale. Perimetry is an important part of evaluation for patients with vision disorders including macular degeneration, retinitis pigmentosa, and diabetic retinopathy. Perimetry measures vision in all parts of the visual field, including the peripheral vision.
Promising Applications to Improve Clinical Vision Care The new paper describes (and illustrates) the use of adaptive optics-guided microperimtery to assess visual fields at an unprecedented level of detail. The technique can not only show limitations in visual fields, but can trace the defect to individual retinal photoreceptor cells. High-speed tracking is used to correct for normal eye movement, or "jitter," that is practically undetectable using conventional imaging techniques.
In addition, by using microscopic blood vessels as anatomical landmarks, the adaptive optics technique permits repeated studies to be repeated over time at a high level of precision. This offers unique opportunities for studying how treatments work on the cellular level, as well as following the effects of treatment over time in individual patients.
"This technique opens new horizons for clinician-scientists, and later clinicians, to better understand, and plot out, the relationships between vision and the retinal photoreceptors at a microscopic level," comments Anthony Adams, OD, PhD, Editor-in-Chief of Optometry and Vision Science. "It enables a new understanding of vision loss in patients with retinal disorders where there are discrete photoreceptor losses -- for example, macular degeneration."
Adaptive optics-guided microperimetery and other advanced imaging technologies described in the special issue have the potential to revolutionize the management of eye diseases, Dr. Read and colleagues believe. They conclude, "With ongoing improvements in imaging speed and resolution, and with the application of innovative methods to improve the clinical usefulness of ocular imaging techniques, the future of ocular imaging is bright!"
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Women Have Bigger Pupils Than Men

ScienceDaily (Apr. 26, 2012) - From an anatomical point of view, a normal, non-pathological eye is known as an emmetropic eye, and has been studied very little until now in comparison with myopic and hypermetropic eyes. The results show that healthy emmetropic women have a wider Pupil diameter than men.

Normal, non-pathological emmetropic eyes are the most common type amongst the population (43.2%), with a percentage that swings between 60.6% in children from three to eight years and 29% in those older than 66.
Therefore, a study determines their anatomical pattern so that they serve as a model for comparison with eyes that have refractive defects (myopia, hypermetropia and stigmatism) pathological eyes (such as those that have cataracts).
"We know very little about emmetropic eyes even though they should be used for comparisons with myopic and hypermetropic eyes" Juan Alberto Sanchis-Gimeno, researcher at the University of Valencia and lead author of the study explained.
The project, published in the journal 'Surgical and Radiologic Anatomy' shows the values by gender for the central corneal thickness, minimum total corneal thickness, white to white distance and Pupil diameter in a sample of 379 emmetropic subjects.
"It is the first study that analyses these anatomical indexes in a large sample of healthy emmetropic subjects" Sanchis-Gimeno states. In recent years new technologies have been developed, such as corneal elevation topography, which allows us to increase our understanding of in vivo ocular anatomy.
Although the research states that there are no big differences between most of the parameters analysed, healthy emmetropic women have a wider Pupil diameter than men.
"It will be necessary to investigate as to whether there are differences in the anatomical indexes studied between emmetropic, myopic and hypermetropic eyes, and between populations of different ethnic origin" the researcher concludes.
How the human eye works
Light penetrates through the Pupil, crosses the crystalline lens and is projected onto the retina, where the photoreceptor cells turn it into nerve impulses, and it is transferred through the optic nerve to the brain. Rays of light should refract so that they can penetrate the eye and can be focused on the retina. Most of the refraction occurs in the cornea, which has a fixed curvature.
The Pupil is a dilatable and contractile opening that regulates the amount of light that reaches the retina. The size of the Pupil is controlled by two muscles: the Pupillary sphincter, which closes it, and the Pupillary dilator, which opens it. Its diameter is between 3 and 4.5 millimetres in the human eye, although in the dark it could reach up to between 5 and 9 millimetres.
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Study Links Genes to Common Forms of Glaucoma

ScienceDaily (Apr. 26, 2012) - Results from the largest genetic study of Glaucoma, a leading cause of blindness and vision loss worldwide, showed that two genetic variations are associated with primary open angle Glaucoma (POAG), a common form of the disease. The identification of genes responsible for this disease is the first step toward the development of gene-based disease detection and treatment.

About 2.2 million people in the U.S. have Glaucoma. POAG is often associated with increased eye pressure but about one-third of patients have normal pressure Glaucoma (NPG). Currently, no curative treatments exist for NPG.
Researchers including lead author Janey Wiggs, M.D., Ph.D., and Lou Pasquale, M.D., Co-Directors of the Harvard Glaucoma Center of Excellence, analyzed DNA sequences of 6,633 participants, half of whom had POAG. Participants were part of two NIH-funded studies: GLAUGEN (Glaucoma Genes and Environment) and NEIGHBOR (NEI Glaucoma Human genetics collaBORation), conducted at 12 sites in the United States. Dr. Pasquale is Director of the Glaucoma Service at Mass. Eye and Ear.
The results, reported online in PLoS Genetics (April 26, 2012), found that two variations were associated with POAG, including NPG. These are the first variants commonly associated with NPG. One variant is in a gene located on chromosome 9 called CDKN2BAS whereas the other variant is in a region of chromosome 8 where it may affect the expression of genes LRP12 or ZFPM2. These genes may interact with transforming growth factor beta (TGF-beta), a molecule that regulates cell growth and survival throughout the body. Previous studies have also implicated TGF-beta in glaucoma.
"This research has provided important new insights into the disease pathogenesis and will make future studies focused on translating this information into the clinic possible. Ultimately we hope to prevent blindness caused by this very common eye disease," said lead author Dr. Wiggs.
"This study has identified an important molecular pathway in the development of POAG. Control of TGF-beta might lead to more effective therapies for this blinding disease," said Dr. Hemin Chin, associate director for Ophthalmic Genetics at the National Eye Institute.
Funding sources for this research include the National Eye Institute, National Human Genome Research Institute, Lions Eye Research Fund, Glaucoma Center of Excellence, the Margolis Fund, and Research To Prevent Blindness.
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Cornea Gene Discovery Reveals Why Humans See Clearly

ScienceDaily (Dec. 12, 2011) — A transparent Cornea is essential for vision, which is why the eye has evolved to nourish the Cornea without blood vessels. But for millions of people around the world, diseases of the eye or trauma spur the growth of blood vessels and can cause blindness.

A new Northwestern Medicine study has identified a gene that plays a major role in maintaining clarity of the Cornea in humans and mice -- and could possibly be used as gene therapy to treat diseases that cause blindness. The paper is published in the Proceedings of the National Academy of Sciences.

"We believe we've discovered the master regulator gene that prevents the formation of blood vessels in the eye and protects the clarity of the Cornea," said lead author Tsutomu Kume, associate professor of medicine at Northwestern University Feinberg School of Medicine and a researcher at Feinberg Cardiovascular Research Institute.

The existence of the gene, FoxC1, was previously known, but its role in maintaining a clear Cornea is a new finding. Working with a special breed of mice that are missing this gene, Kume and colleagues found abnormal vascular formations, or blood vessels, streaking their Corneas and blocking light.

When Kume discovered the Corneal blood vessels in the mutant mice, he called a collaborator at the University of Alberta in Canada, Ordan Lehmann, MD, professor of ophthalmology and medical genetics.

Lehmann found that his patients who have a single copy of this mutated FoxC1 gene -- and who have congenital glaucoma -- also have abnormal blood vessel growth in their eyes.

"The exciting thing is by showing the loss of FoxC1 causes vascularization of the Cornea, it means increasing levels of the gene might help prevent the abnormal growth of blood vessels, potentially in multiple eye disorders that cause blindness," said Lehmann, a coauthor on the paper. "That's the hope." One possible use might be in corneal transplants, he said, where the growth of new blood vessels onto the transplanted cornea is a major problem.

Kume next plans to test the gene therapy in mice to see if injecting FoxC1 inhibits the formation of blood vessels in the cornea.

The research is funded by National Institutes of Health and Canadian Institutes of Health Research.

http://www.sciencedaily.com/releases/2011/12/111212153121.htm

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New Glaucoma Test Allows Earlier, More Accurate Detection

Cumbersome Glaucoma tests that require a visit to the ophthalmologist could soon be history thanks to a home test developed by a UA engineer.

Phoenix ophthalmologist Dr. Gholan Peyman demonstrates a prototype Glaucoma test instrument that's noninvasive and simpler to use than current procedures. It can also be used in situations that are difficult or impossible with current tests. (Credit: Image courtesy of University of Arizona College of Engineering)

The self-test instrument has been designed in Eniko Enikov's lab at the UA College of Engineering. Gone are the eye drops and need for a sterilized sensor. In their place is an easy-to-use probe that gently rubs the eyelid and can be used at home.

"You simply close your eye and rub the eyelid like you might casually rub your eye," said Enikov, a professor of aerospace and mechanical engineering. "The instrument detects the stiffness and, therefore, infers the intraocular pressure." Enikov also heads the Advanced Micro and Nanosystems Laboratory.

While the probe is simple to use, the technology behind it is complex, involving a system of micro-force sensors, specially designed microchips, and math-based procedures programmed into its memory.

Enikov began working on the probe four years ago in collaboration with Dr. Gholan Peyman, a Phoenix ophthalmologist. "We went through several years of refinement and modifications to arrive at the current design," Enikov noted.

The National Science Foundation has funded the work, and Enikov and Peyman now are seeking investors to help fund final development and commercialization of the product.

In addition to screening for Glaucoma, an eye disease that can lead to blindness if left untreated, the device corrects some problems with the current procedure, and can be used to measure drainage of intraocular fluid.

"Eye pressure varies over a 24-hour cycle," Enikov said. "So it could be low at the doctor's office and three hours later it might be high. With only a single test, the doctor might miss the problem. Having the ability to take more frequent tests can lead to earlier detection in some cases."

Once the diagnosis is made, several treatments are available. The question then is: How effective are they? Patients could use the probe at home to trace how much the pressure decreases after using eye drop medications, for instance.

"One of the reasons pressure builds up in the eye is because fluid doesn't drain properly," Enikov noted. "Currently, there are no methods available to test drainage."

Current tests require applying pressure directly to the cornea, but only very light pressure is safe to use, and it doesn't cause the fluid to drain.

"Our technique allows us to apply slightly greater pressure, but it's still not uncomfortable," he said. "It's equivalent to rubbing your eye for a brief period to find out if the pressure changes. If it does, we know by how much and if there is a proper outflow of intraocular fluid."

Sometimes, a surgical shunt is used to help fluid drain from the eye. "The problem with Glaucoma shunts is they can plug up over time," Enikov noted. "Or if they're not properly installed, they may drain too quickly. So you would want to know how well the shunt is working and if it is properly installed. Our device could help answer those questions."

In another scenario, certain patients cannot be tested for Glaucoma using currently available procedures. "If a patient had cataract surgery or some other surgery through the cornea, the cornea sometimes thickens," Enikov said. "The cornea's structure is different, but our test remains accurate because it's not applied to the cornea."

Instead, it presses the entire eyeball, much as you might press a balloon to determine its stiffness.

"The innovation with our device is that it's noninvasive, simpler to use and applies to a variety of situations that are either difficult to address or impossible to test using the current procedures," Enikov said. "That's why we're so excited about this probe. It has great potential to improve medical care, and significant commercial possibilities, as well."

http://www.sciencedaily.com/releases/2011/01/110104101331.htm

The above story is reprinted from materials provided by University of Arizona College of Engineering. The original article was written by Ed Stiles.

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The Pupils Are the Windows to the Mind

The eyes are the window into the soul -- or at least the mind, according to a new paper published in Perspectives on Psychological Science, a journal of the Association for Psychological Science. Measuring the diameter of the Pupil, the part of the eye that changes size to let in more light, can show what a person is paying attention to. Pupillometry, as it's called, has been used in social psychology, clinical psychology, humans, animals, children, infants -- and it should be used even more, the authors say.

The Pupil is best known for changing size in reaction to light. In a dark room, your Pupils open wide to let in more light; as soon as you step outside into the sunlight, the Pupils shrink to pinpricks. This keeps the retina at the back of the eye from being overwhelmed by bright light. Something similar happens in response to psychological stimuli, says Bruno Laeng of the University of Oslo, who cowrote the paper with Sylvain Sirois of Université du Québec à Trois-Rivières and Gustaf Gredebäck of Uppsala University in Sweden. When someone sees something they want to pay closer attention to, the Pupil enlarges. It's not clear why this happens, Laeng says. "One idea is that, by essentially enlarging the field of the visual input, it's beneficial to visual exploration," he says.

However it works, psychological scientists can use the fact that people's Pupils widen when they see something they're interested in.

Laeng has used Pupil size to study people who had damage to the hippocampus, which usually causes very severe amnesia. Normally, if you show one of these patients a series of pictures, then take a short break, then show them another series of pictures, they don't know which ones they've seen before and which ones are new. But Laeng measured patients' Pupils while they did this test and found that the patients did actually respond differently to the pictures they had seen before. "In a way, this is good news, because it shows that some of the brains of these patients, unknown to themselves, is actually capable of making the distinction," he says.

Pupil measurement might also be useful for studying babies. Tiny infants can't tell you what they're paying attention to. "Developmental psychologists have used all kinds of methods to get this information without using language," Laeng says. Seeing what babies are interested in can give clues to what they're able to recognize -- different shapes or sounds, for example. A researcher might show a child two images side by side and see which one they look at for longer. Measuring the size of a baby's Pupils could do the same without needing a comparison.

The technology already exists for measuring Pupils -- many modern psychology studies use eye-tracking technology, for example, to see what a subject is looking at, and Laeng and his coauthors hope to convince other psychological scientists to use this method.

http://www.sciencedaily.com/releases/2012/01/120127162800.htm

The above story is reprinted from materials provided by Association for Psychological Science.

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Contact Lenses Provide Extended Pain Relief to Laser Eye Surgery Patients

Contact Lenses

Provide Extended Pain Relief to Laser Eye Surgery Patients

Scientists are reporting development of Contact lenses that could provide a continuous supply of anesthetic medication to the eyes of patients who undergo laser eye surgery -- an advance that could relieve patients of the burden of repeatedly placing drops of medicine into their eyes every few hours for several days.Their report appears in ACS' journal Langmuir

.

Anuj Chauhan and colleagues explain that more than 1 million laser eye correction procedures are performed each year in the U.S. The surgery enables most patients to see clearly without eye glasses or Contact lenses. The procedure known as LASIK is the most common type of laser eye surgery, but complications can develop if the patient undergoes trauma or is hit very hard at any time after the procedure. Photorefractive keratectomy (PRK) doesn't have this complication, and that's why it is preferred for athletes and those in the military. A downside to PRK, however, is a longer period of pain after surgery. To ease their pain, PRK patients place drops of several medications, including anesthetics, into their eyes every few hours, which can interfere with daily life and increase the risk of drug overdose. PRK patients receive a special "bandage Contact lens" after surgery to help the outer layer of the eye heal.

The researchers tested whether anesthetics loaded onto this type of lens could release the drugs over time automatically. They found that adding vitamin E to the lenses extended the time of release of three commonly used anesthetics from just under two hours to up to an entire day -- or a few days in some instances. The vitamin E acts as a barrier, keeping the anesthetics on the eye, right where they are needed. The researchers say that, in the future, these lenses could serve as bandage Contact lenses after PRK surgery while also delivering necessary pain medications.

The authors acknowledge funding from the University of Florida.

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Eye Allergies

 

Eye Allergies often are hereditary, and occur due to processes associated with other types of allergic responses.

When an allergic reaction takes place, your eyes may be overreacting to a substance perceived as harmful, even though it may not be. These substances are called allergens.

For example, dust that is harmless to most people can cause excessive production of tears and mucus in eyes of overly sensitive, allergic individuals.

Allergies can trigger other problems, such as conjunctivitis (pink eye) and asthma. Combined nasal and eye Allergies create a condition known as rhinoconjunctivitis.

About 30 percent to 50 percent of U.S. residents have allergy symptoms. And about 75 percent of those symptoms affect the eyes.*

Allergy Symptoms and Signs

Common signs of Allergies include:

• Red, swollen or itchy eyes
• Runny nose
• Sneezing and coughing
• Itchy nose, mouth or throat
• Headache from sinus congestion

Beyond more obvious symptoms, you also may feel fatigued and could suffer from lack of sleep.

What Causes Eye Allergies?

Many allergens are in the air, where they come in contact with your eyes and nose. Airborne allergens include pollen, mold, dust and pet dander.

Other causes of Allergies, such as certain foods or bee stings, do not typically affect the eyes the way airborne allergens do. Adverse reactions to certain cosmetics or drugs such as antibiotic eye drops also may cause eye Allergies.

Some people actually are allergic to the preservatives in eye drops such as those used to lubricate dry eyes. In this case, you may need to use a preservative-free brand.

General Eye Allergy Treatment

Avoidance. The most common "treatment" is to avoid what's causing your eye allergy. Itchy eyes? Keep your home free of pet dander and dust and keep pets off the furniture. Stay inside with the air conditioner on when a lot of pollen is in the air. Use high quality furnace filters that trap common allergens and replace the filters frequently.

Make sure you wear wraparound sunglasses to help shield your eyes from allergens, and drive with your windows closed during allergy season.

Medications. If you're not sure what's causing your eye Allergies, or you're not having any luck avoiding them, your next step probably will be medication to alleviate the symptoms.

Over-the-counter and prescription medications each have their advantages; for example, over-the-counter products often are less expensive, while prescription ones usually are stronger and may be more effective.

Eye drops are available as simple eye washes, or they may have one or more active ingredients such as antihistamines, decongestants or mast cell stabilizers that inhibit inflammation. Antihistamines relieve many symptoms caused by airborne allergens, such as itchy, watery eyes, runny nose and sneezing. Decongestants help shrink swollen nasal passages for easier breathing.

Relief for Watery, Itchy Eyes

Common causes of excessively watery eyes are allergies and dry eye syndrome — two very different problems.

With allergies, your body's release of histamine causes your eyes to water, just as it may cause your nose to run.

It may seem illogical that dry eye syndrome could cause watery eyes. But sometimes an underlying dry eye condition stimulates your tear glands to overproduce the watery component of your eye's tears as a protective response, leading to watery eyes.

Decongestants clear up redness. They contain vasoconstrictors, which make the blood vessels in your eyes smaller, lessening the apparent redness. They treat a symptom but not the cause of eye allergies.

In fact, with extended use, the blood vessels can become dependent on the vasoconstrictor to stay small. When you discontinue the eye drops, the vessels actually get bigger than they were in the beginning. This process is called rebound hyperemia, and the result is that your red eyes could worsen over time.

Some products have ingredients that act as mast cell stabilizers, which alleviate redness and swelling. Mast cell stabilizers are similar to antihistamines. But while antihistamines are known for their immediate relief, mast cell stabilizers are known for their long-lasting relief.

Eye Allergy News

Have Fall Allergies? You Might Not Want To Live in One of These Cities

October 2011 — Is your town one of the top 100 most challenging in the country for fall allergies? Check the new list compiled by the Asthma and Allergy Foundation of America.

Knoxville, Tenn. is number one this year, joining other pollen-ridden southern and midwestern cities. The next four on the list are: Dayton, Ohio; McAllen, Texas; Jackson, Miss.; and Oklahoma City.

It's not just pollen that's causing the problem. Indoor allergens such as dust mites, pet dander and mold also trigger allergic reactions in the fall.

Please click here for the top 100 U.S. cities for fall allergies.

Also, take a look at today's pollen count map.

Antihistamines, decongestants and mast cell stabilizers are available in pill form, but pills don't work as quickly as eye drops or gels to bring eye relief.

Nonsteroidal anti-inflammatory drug (NSAID) eye drops may be prescribed to decrease swelling, inflammation and other symptoms associated with seasonal allergic conjunctivitis, also called hay fever.

Prescription corticosteroid eye drops also may provide similar, quick relief. However, steroids have been associated with side effects such as increased inner eye pressure (intraocular pressure) leading to glaucoma and damage to optic nerve.

Steroids also have been known to cause the eye's natural lens to become cloudy, producing cataracts.

Check the product label or insert for a list of side effects of over-the-counter medications. For prescription medication, ask your doctor. In some cases, combinations of medications may be used.

You may benefit from immunotherapy, in which an allergy specialist injects you with small amounts of the allergen to help you gradually build up immunity.

Eye Allergies and Contact Lenses

Even if you are generally a successful contact lens wearer, allergy season can make your contacts uncomfortable. Airborne allergens can get on your lenses, causing discomfort. Allergens also can stimulate the excessive production of natural substances in your tears, which can bind to your contacts and cause blur and additional discomfort. Pollen maps can help you determine when allergens are present.

Ask your eye doctor about eye drops that can help relieve your symptoms and keep your contact lenses clean. Certain drops can discolor or damage certain lenses, so it makes sense to ask first before trying out a new brand.

Another alternative is daily disposable contact lenses, which are discarded nightly. Because you replace them so frequently, these types of lenses are unlikely to develop irritating deposits that can build up over time and cause or heighten allergy-related discomfort.

By Gina White, with updates by Marilyn Haddrill; reviewed by Vance Thompson, MD

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Eye Color

 

Eye Color often is the genetic trait that fascinates parents the most as a child develops. Will the child's eyes be black, brown, blue, gray, green, hazel or some combination of colors?

How a child looks depends on the genetic material each parent contributes to the child. But the parents' genes can mix and match in many different ways. The influences from each parent aren't known until — surprise — after the child is born!

How Eye Color Develops

The colored part of the eye is called the iris, which has pigmentation that determines our Eye Color.

Human Eye Color originates with three genes, two of which are well understood. These genes account for the most common colors — green, brown, and blue. Other colors, such as gray, hazel and multiple combinations are not fully understood or explainable at this time.

Her eyes may be blue only temporarily; babies' eyes can change color if the brown pigment melanin develops as they grow.

We used to think of brown being "dominant" and blue being "recessive." But modern science has shown that Eye Color is not at all that simple.

Also, Eye Colors don't come out as a blend of the parents' colors, as in mixing paint. Each parent has two pairs of genes on each chromosome. So multiple possibilities exist, depending on how the "Wheel of Fortune" spins.

Dutch researchers have announced they are working on ways to determine Eye Color of adults with sophisticated DNA analysis that can predict with 90 percent accuracy whether people have brown or blue eyes.

In May 2010, the same researchers said they were closing in on the ability to more accurately predict even variable Eye Colors via DNA analysis and new understanding of how genetics govern Eye Color.

Researchers said these discoveries also have implications for forensic investigations at crime scenes where recovered DNA may give clues about the actual appearance of suspects.

Eye Color Poll Results

Which Eye Color Do You Think Is Most Attractive? Here's the Answer

August 2011 — After collecting 6,468 responses to our eye color poll, we thought it was time to share the results with you:

Green is the winner among our site visitors, but responses were spread pretty well over most of the other colors, too.

To some, eye color isn't that significant. As someone said on our Facebook page, "All eye colors can be 'the most attractive.' ... Your eye color has to be about you and express the truth of you to others."

Another person posted this comment about eye health being much more important: "The most attractive color is the white of the eye when it is clear and bright, which makes any iris beautiful." — L.S.

Most babies are born with blue eyes that can darken in their first three years. Darkening occurs if melanin, a brown pigment usually not present at birth, develops with age.

Children can have completely different eye colors than either of their parents. But if both parents have brown eyes, it's most likely that their children also will have brown eyes.

The darker colors tend to dominate, so brown tends to win out over green, and green tends to win out over blue.

However, a brown/blue parent mix doesn't automatically produce a brown-eyed child.

Some children are born with irises that don't match in color. Usually this is caused by faulty developmental pigment transport, local trauma either in the womb or shortly after birth or a benign genetic disorder. Other causes can be inflammation, freckle (diffuse nevus) of the iris and Horner's syndrome.

Having an early eye exam is important to make sure nothing serious is going on — and "nothing serious" is the most common finding.

Changes in Eye Color

The iris is a muscle that expands and contracts to control pupil size. The pupil enlarges in dimmer lighting and grows smaller in brighter lighting. The pupil also shrinks when you focus on near objects, such as a book you are reading.

Eye Color News

Can We Change Eye Color With Surgery?

November 2011 — A company called Stroma Medical is developing a way to turn brown eyes blue permanently, using a laser.

How it works exactly is unclear, but it has been reported that the laser releases the brown pigments from the iris, and what's left is a blue color that develops over a couple of weeks. One downside may be that the iris color afterward can't be accurately predicted.

The procedure is not FDA-approved and will require more testing before U.S. availability is possible. A potential safety question is, what happens to the released pigments within the eye?

For more information, watch this video of a news report on KTLA.com. — L.S.

When the pupil size changes, the pigments in the iris compress or spread apart, changing the eye color a bit.

Certain emotions can change both the pupil size and the iris color. That's why some people say their eyes change colors when they're angry or loving.

Eye color also can change with age. This happens in 10 to 15 percent of the Caucasian population (people who generally have lighter eye colors).

For instance, my once very brown eyes are now hazel, a combination of brown and green. However, some hazel eyes actually get darker with age.

Note that if your adult eye color changes pretty dramatically, or if one eye changes from brown to green or blue to brown (called heterochromia), it's important to see your eye doctor. Eye color changes can be a warning sign of certain diseases, such as Fuch's heterochromic iridocyclitis, Horner's syndrome or pigmentary glaucoma.

Ultimately, if you don't like the eye color you inherited, you can always change it with colored contact lenses. But remember, even colored contact lenses are a prescription medical device and must be prescribed and monitored by an eye doctor. Don't buy them

over the Internet or get them from a friend without having an eye doctor's prescription!

By Burt Dubow, OD

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