Eye color is a hereditary trait that depends on the genes of both parents, as well as a little bit of mystery. The color of the eye is based on the pigments in the iris, which is a colored ring of muscle located at the center of the eye (around the pupil) that helps to control the amount of light that comes into your eye. Eye color falls on a spectrum of color that can range from dark brown, to gray, to green, to blue, with a whole lot of variation in between. 

Genetics

The genetics of eye color are anything but straightforward. In fact children are often born with a different eye color than either of their parents. For some time the belief was that two blue-eyed parents could not have a brown-eyed child, however, while it’s not common, this combination can and does occur. Genetic research in regards to eye color is an ongoing pursuit and while they have identified certain genes that play a role, researchers still do not know exactly how many genes are involved and to what extent each gene affects the final eye color.

The Iris

Looking at it simply, the color of the eye is based on the amount of the pigment melanin located in the iris. Large amounts of melanin result in brown eyes, while blue eyes result from smaller amounts of the pigment. This is why babies that are born with blue eyes (who often have smaller amounts of melanin until they are about a year old) often experience a darkening of their eye color as they grow and develop more melanin in the iris. In adults across the globe, the most common eye color worldwide is brown, while lighter colors such as blue, green and hazel are found predominantly in the Caucasian population. 

Abnormal Eye Color

Sometimes the color of a person’s eyes are not normal. Here are some interesting causes of this phenomenon.

Heterochromia, for example, is a condition in which the two eyes are different colors, or part of one eye is a different color. This can be caused by genetic inconsistencies, issues that occur during the development of the eye, or acquired later in life due to an injury or disease. 

Ocular albinism is a condition in which the eye is a very light color due to low levels of pigmentation in the iris, which is the result of a genetic mutation. It is usually accompanied by serious vision problems. Oculocutaneous albinism is a similar mutation in the body’s ability to produce and store melanin that affects skin and hair color in addition to the eyes.

Eye color can also be affected by certain medications. For example, a certain glaucoma eye drop is known to darken light irises to brown, as well as lengthen and darken eyelashes.

Eye Color – It’s More Than Meets the Eye

It is known that light eyes are more sensitive to light, which is why it might be hard for someone with blue or green eyes to go out into the sun without sunglasses. Light eyes have also shown to be a risk factor for certain conditions including age-related macular degeneration (AMD).  

Color Contact Lenses

While we can’t pick our eye color, we can always play around with different looks using colored contact lenses. Just be sure that you get a proper prescription for any contact lenses, including cosmetic colored lenses, from an eye doctor! Wearing contact lenses that were obtained without a prescription could be dangerous to your eyes and your vision.  

Age-related macular degeneration is a serious condition that can threaten your vision and general well-being. Characterized by the deterioration of the central area of the retina called the macula which is responsible for focused vision, the disease gradually reduces your central vision. This affects the ability to see fine details, recognize faces, read, drive, watch television and even use a computer. The disease often leaves some vision resulting in a condition called low vision, which is considered a form of legal blindness. 

AMD is the leading cause of vision loss in the older population and the numbers are expected to increase as Americans and Canadians continue to live longer. 

What causes AMD and how can it be prevented?

As you can see by the name, the primary risk factor of AMD is age, particularly over age 50. Caucasian women are the most common demographic to be hit with this ocular disease; family medical history and having lighter colored hair, skin and eyes play a large role as well. However, several lifestyle factors have been shown to cause an increase in AMD development; so there may be ways to reduce your risk, even if you have a genetic predisposition.  

In fact, most of the controllable risk factors pose general health risks that cause a plethora of health issues, so addressing them will boost your overall health and wellness, in addition to protecting your eyes and vision from AMD. Here are 6 ways to prevent AMD and the vision loss that accompanies it:

1. Stop Smoking

Smoking, and even living with a smoker, have been shown to significantly increase your risks of developing AMD to between 2-5 times the risk of non-smokers! If you also have a hereditary risk, smoking compounds that risk tremendously.   

2. Get Active 

Studies show that obesity and a sedentary lifestyle increase the risk of advanced macular degeneration that leads to significant vision loss. Maintaining a healthy weight and being active  can reduce your risk. That could be as easy as regular walking, at least 3 times a week for 30 minutes.

3. Control Blood Pressure

Since the eye contains many tiny blood vessels, high blood pressure can have a serious impact on the health of your eyes. Have your blood pressure checked by your doctor and follow any medical advice you are given to reduce high blood pressure, whether that includes diet, exercise or medication. 

4. Choose a Healthy Diet

A diet rich in antioxidants has been shown to protect against AMD.  Antioxidants can be found in abundance in dark green leafy vegetables such as spinach, broccoli, kale and collard greens, as well as orange fruits and vegetables such as peppers, oranges, mango and cantaloupe.  Eating a wide range of fresh fruits and vegetables, 5-9 servings a day, as well as fish, which contain Omega-3, and avoiding sugar and processed foods will help to keep your body healthy in many ways, including reducing your risk of AMD.  

5. Use UV and Blue Light Protection

Long-term exposure to UV rays from the sun and blue light (from digital devices among other things) have been linked to AMD. Make sure you wear sunglasses every time you are exposed to sunlight and wear blue light blocking glasses when you are viewing a digital device or computer for extended periods of time. 

6. Take Supplements*

Certain nutritional supplements have been shown to slow the progression of AMD and the vision loss that accompanies it. This formula of supplements was developed from a 10 year study of 3,500 people with AMD called the Age-Related Eye Disease Study (AREDS) and its successor AREDS2. It is not recommended to take supplementation as a preventative measure but rather only if you are diagnosed with intermediate or advanced AMD.

*Speak to your eye doctor before you make a decision about this option.

During your yearly comprehensive eye exam, your eye doctor will screen for early signs of AMD and recommend treatment if it’s detected. If you’re at greater risk – because of your age or a family history of AMD / blindness of unknown cause, for example – additional testing may be necessary.

AMD can be a devastating disease. If you are aware that you are at risk, it is worthwhile to do everything you can to prevent it and the vision loss that it can bring. Take the time to understand AMD and do what it takes to lower your chances of knowing its effects first-hand. 

Your toddler may show every sign of good eyesight including the ability to see objects in the distance, however that doesn’t necessarily mean that he or she doesn’t have a vision problem.

Amblyopia is one common eye condition that is often hidden behind the appearance of good eyesight.  

Also known as “lazy eye” it usually occurs when the brain begins to ignore the signals sent by one eye, often because that eye is weaker and doesn’t focus properly. Sometimes it can occur in both eyes, in which case it’s called bilateral amblyopia. This eye condition is especially common in preemies, and tends to run in families as well, so it’s important to provide your eye doctor with a complete medical and family history.

There are several factors that can cause amblyopia to develop. These include:

• astigmatism, 
• high nearsightedness or farsightedness, 
• uneven eye development as an infant,
• congenital cataract (clouding of the lens of the eye),
• strabismus (where the eyes are misaligned or “cross-eyed”)

However in many cases of amblyopia there may be no obvious visible structural differences in the eye. In addition to the fact that the eyes may look normal, vision often appears fine as the brain is able to compensate for the weaker eye by favoring the stronger one. Because of this, many children live with their eye condition for years before it is diagnosed. Unfortunately, as a person ages, the brain loses some of its plasticity (how easy it is to train the brain to develop new skills), making it much harder – if not impossible – to treat amblyopia in older children and adults. That’s why it’s so important for infants and young children to have a thorough eye exam.

Are There Any Signs of Amblyopia?

If you notice your child appears cross-eyed, that would be an indication that it’s time for a comprehensive eye exam to screen for strabismus and amblyopia development.

Preschoolers with amblyopia sometimes show signs of unusual posture when playing, such as head tilting, clumsiness or viewing things abnormally close.

However, often there are no signs or symptoms. The child typically does not complain, as he or she does not know what normal vision should look like. Sometimes the condition is picked up once children begin reading if have difficulty focusing on the close text. The school nurse may suggest an eye exam to confirm or rule out amblyopia following a standard vision test on each eye, though it might be possible to pass a vision screening test and still have amblyopia. Only an eye doctor can make a definitive diagnosis of the eye condition.

So How Do You Know If or When To Book a Pediatric Eye Exam?

Comprehensive eye and vision exams should be performed on children at an early age. That way, hidden eye conditions would be diagnosed while they’re still more easily treatable. An eye exam is recommended at 6 months of age and then again at 3 years old and before entering first grade. The eye doctor may need to use eye drops to dilate the pupils to confirm a child’s true refractive error and diagnose an eye condition such as amblyopia.

Treatment for Amblyopia

Glasses alone will not completely correct vision with amblyopia in most cases, because the brain has learned to process images from the weak eye or eyes as blurred images, and ignore them. There are several non-surgical treatment options for amblyopia. While your child may never achieve 20/20 vision as an outcome of the treatment and may need some prescription glasses or contact lenses, there are options that can significantly improve visual acuity.

Patch or Drops

In order to improve vision, one needs to retrain the brain to receive a clear image from the weak eye or eyes. In the case of unilateral amblyopia (one eye is weaker than the other), this usually involves treating the normal eye with a patch or drops to force the brain to depend on the weak eye. This re-establishes the eye-brain connection with the weaker one and strengthens vision in that eye. If a child has bilateral amblyopia, treatment involves a regimen of constantly wearing glasses and/or contact lenses with continual observation over time. 

Your eye doctor will prescribe the number of waking hours that patching is needed based on the visual acuity in your child’s weak eye; however, the periods of time that you chose to enforce wearing the patch may be flexible. During patching the child typically does a fun activity requiring hand eye coordination to stimulate visual development (such as a favorite video game, puzzle, maze etc) as passive activity is not as effective. 

The earlier treatment starts, the better the chances are of stopping or reversing the negative patterns formed in the brain that harm vision. Amblyopia treatment with patches or drops may be minimally effective in improving vision as late as the early teen years (up to age 14) but better results are seen in younger patients.

Vision Therapy

Many optometrists recommend vision therapy to train the eyes using exercises that strengthen the eye-brain connection. While success rates tend to be better in children, optometrists have also seen improvements using this occupational therapy type program to treat amblyopia in adults. 

The key to improvement through any non-surgical treatment for amblyopia is compliance. Vision therapy exercises must be practiced on a regular basis. Children that are using glasses or contact lenses for treatment, must wear them consistently. Your eye doctor will recommend the schedule of the patching, drops, or vision therapy eye exercise and the best course of treatment.

Amblyopia: Take-home Message

Even if your child is not showing any signs of vision problems, and especially if they are, it is important to have an eye examination with an eye doctor as soon as possible, and on a regular basis. While the eyes are still young and developing, diagnosis and treatment of eye conditions such as amblyopia are greatly improved.