One of the Greatest Lies Ever Told: Carrots

Carrots do help guard the health of your eyes, but do not give you "super vision"

It’s not that carrots aren’t nutritious, they are indeed important in keeping your eyes healthy (and actually, your vision would in fact deteriorate if you had a carotene or vitamin A deficiency), however they do not magically enhance your vision, or a fighter jet pilot’s night vision for that matter. (source 1)

And so the little fib was fabricated, in World War II, but for good reason. The Royal Air Force had a pilot, John Cunningham, with an exceptionally good record of shooting down enemy planes at night. They even nicknamed him, “Cat Eyes” and boasted that it was his love of carrots that gave him his super-human night vision. The British government then began a whole campaign about carrots, which was one food in plentiful supply during the war, celebrating their nutritional value and saying that they would help improve your night vision during the blackouts which were frequent in WWII. (source 2)

In reality, the Royal Air Force was trying to hide the fact that the UK was the first country to successfully employ RADAR (RAdio Detection And Ranging) and that was giving their pilots an edge while shooting down bombers at night. The theory of carrots improving the RAF’s night vision did not raise suspicion among the Germans, carrots enhancing the eyes was already a theme in German folklore. (source 2)

Somehow, over the years, the myth was never fully debunked and to this day, I still have patients asking if carrots will eliminate their need for glasses or reduce their prescription. It will not. But it is important to incorporate vegetables and fruits into your regular diet as this will help keep your eyes well-nourished and healthy and can even slow the progression of certain eye conditions and illnesses like cataracts and macular degeneration. A high dosage of Vitamin A is also recommended for patients with the most common form of Retinitis Pigmentosa but only under careful watch and monitoring by their doctor. (source 3) Never over-dose or mega-dose Vitamin A, just like too little vitamin A can harm you, so can too much! (source 4) As a general guideline, adults over age 19 should be getting between 2000-3000 IU (international units) of vitamin A daily in their diets, that amount can be found in one cup of spinach (raw) which contains 2813 IU of vitamin A or if you are not a spinach fan, the good old carrot does provide plenty of vitamin A, about 8666 IU in one large, raw carrot (about 7 1/2 inches long).

So, in conclusion, carrots will keep you super healthy and we’ll just leave it at that. And if you still think carrots are the magical remedy for your need for vision correction, just take a look at the picture at the top of this article. Even “Dr. Carrot” is wearing glasses.

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Celebrating 10,000 views!

It's all Thanks to YOU!

It happened! I have hit 10,000 views on my eye blog! I feel like setting off fireworks! I feel like celebrating! I also feel like thanking all of those you have read it, inspired me, helped me with ideas, editing, pictures, encouraged me and referred others here! I will continue to write, and am as always, accepting ideas and suggestions from friends of the eye blog and readers. I don’t know where this journey of science writing will take me but just knowing that I have helped people get some information and answers that they couldn’t find elsewhere gives me the excitement to keep going and keep writing. It is something I love to do! Thank you so very much!

Sincerely,

Cheryl G. Murphy, OD

Go ahead, LIKE me on Facebook so you’ll hear about new blog posts first or have a little birdie tell you when my newest articles are posted on Twitter.

Great quote: "A journey of a thousand miles begins with a single step."

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The Optic Chiasm, how do neural pathways for vision know to cross to the other side of the brain?

A new study shows VEGF164, a molecule commonly triggering blood vessel growth, surprisingly contributes to the neural development of your vision

There is more to vision than just your eyeballs. Sure information and images are collected by the eye and the retina but that info is then transmitted to the brain to be analyzed and interpreted in the visual cortex. You could sort of say your brain tells your eyes what you are seeing, or at least what all that visual data means. How does the info get from your eyes to your brain? Along perhaps the original ‘information superhighway’ well, at least an information superhighway of VISION known as the Visual Pathway.

The Visual Pathway starts in the retina, which is the sight-seeing tissue that lines the inside of each eye. This tissue changes the images you are seeing into chemical signals, then electrical signals. The electrical signals travel along a series of retinal ganglion nerve cells to the brain. You can think of these nerve cells as vision highways. Early along their path in the brain, the highways from each eye meet at a fork in the road. This is known as the optic chiasm and it is shaped like an X because there are two ‘entrances’ to the chiasm where information comes in from each eye  and then two exits from the chiasm to the right and left hemispheres of the brain. At this X intersection, some information from the right eye gets transferred to the left side of the brain and some information from the left eye gets transferred to the right side of the brain.  So, why the crossover?

Well, we know that images from both eyes (put together in the brain) are essential for binocular vision which gives us our depth perception and 3-D vision. But what triggers the nerve cells from each eye to find their way to the brain during visual development? And what triggers them to swap to different sides of the brain? Recent research may have the beginning of a surprising new answer.

Dr. Lynda Erskine, of the University of Aberdeen and Dr. Christiana Ruhrberg, of the University College London, have conducted research on visual development in mice and shockingly discovered that VEGF164, a molecule usually known for triggering the growth of blood vessels, is actually leading the nerve cells across the chiasm and causing neural cells to cross over to opposite sides of the brain during visual development. They saw that in mice who lacked VEGF 164, there was no crossing of ganglion cells at the optic chiasm. (source 1) Who knew that something we thought only would affect the development of blood vessels in the brain would also be responsible for neuron placement and organization!

The process of vision is so complex and we are learning more about it with each new study. The next time you are playing your favorite 3-D video game or kicking a soccer ball, you can thank your optic chiasm and VEGF 164 for optimizing your vision during your brain’s development, giving you all the info you need to see binocularly! (Just Kidding!)

Keep your eye on the ball, I'll keep my 'Eye on the News' for you!

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Disclaimer

The opinions expressed on this site and by Dr. Cheryl G. Murphy are published for educational and informational purposes only, and are not intended as a diagnosis, treatment or as a substitute for professional medical advice, diagnosis and treatment. Please consult a local physician or other eye care health care professional for your specific health care and/or medical needs or concerns.

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By Request: Myopic Macular Degeneration

Myopic Macular Degeneration can disrupt the central vision of young people making it difficult for them to focus on reading and other activities but there are new treatment options and research which are giving them new hope!

I received this topic by request from a lovely, young woman who has this condition. Although I never examined her myself I feel the need to help others understand the conditions they themselves face and also feel the responsibility to educate others out there on this very important subject. Myopic Macular Degeneration is not to be confused with its similar sounding eye illness, Age-related Macular Degeneration. By contrast, Myopic Macular Degeneration usually happens to young people who have a high amount of nearsight and face complications from elongation of the eye and the stretching of its structures within.

As I was writing this article, I found it to be a tougher topic to present than I thought it would be. There is still much to be learned about the exact reasons and ways this condition progresses. Various treatment options and preventative measures have been tried in an effort to halt this condition but there has not been a true, definitive answer on how to stop it. The good news is, it is starting to draw more and more attention especially with the most recent discoveries of the anti-VEGF drugs being more effective than older treatments such as photodynamic therapy or PDT. (source 4) The exciting thing about anti-VEGF drugs is that they target and block ‘vascular endothelial growth factor’ which they believe is a signal that triggers the growth of new blood vessels. New blood vessel growth below the retina (choroidal neovascularization) is one of the potential dangers in Myopic Macular Degeneration. These anti-VEGF drugs are administered by intravitreal injections at intervals determined by a patient’s doctor in hopes to prevent a recurrence of choroidal neovascularization in the direct center of the retina, the macula. They are giving new hope to patients and doctors alike.

In order to really understand myopic macular degeneration, let’s first talk about just plain myopia or nearsightedness. We’ll then move on to Degenerative Myopia and then to Myopic Macular Degeneration.

Physiological (common) Myopia:

In the simplest of terms, Myopia or Nearsightedness can occur in the eye either because ‘the eye is too long or too strong.’ This means that the eye has an axial length greater than average or the combined ocular power of the cornea and lens is higher than what it should be or both. If the eye is too long or too strong, the image of what you are seeing will focus ‘too soon,’ in front of the retina. These leads to a fuzzy image being captured by the retina and thus results in blurry vision. Usually this disparity of optics can be easily corrected for with contact lenses or glasses which focuses the eye’s image right back to where it should be collected in order to yield good, crisp clear vision. Myopia is usually considered to be just a variation of normal eyes if the prescription is around -6.00 or less and it is said to be “the most common eye disorder worldwide.” (source 1)

Degenerative Myopia:

If your prescription for glasses is much higher than a -6.00, and has gotten progressively worse as you grew older and into your middle age years, there may be a genetic component to your myopia causing the eye to become very long (in its axial length). Degenerative Myopia can be very dangerous to the health of the eye because it can lead to vision loss by either myopic macular degeneration or by a retinal detachment. Also, “more severe myopia and longer axial lengths have been linked to specific pathologies such as cataract, glaucoma, or lattice degeneration.” (source 2) Patient education and proper understanding of these complications are important steps in trying to help patients who suffer from Degenerative Myopia to avoid potential vision loss.

The elongation of the eye is what happens first in Degenerative Myopia. When the eye is much longer than it is wide, there is stretching of the tissues inside the eye and stretching of the retina. Sometimes stretching the retina is like stretching a t-shirt. If it is stretched too far and for too long, it can start to thin and little tiny holes and tears can develop in the retina. When this happens, your doctor will see signs in your eye such as posterior staphyloma, breaks in Bruch’s membrane and lacquer cracks which are complications of scleral thinning and eye elongation. These set the stage for choroidal neovascularization to occur which is new blood vessel growth just beneath the retina. (source 1) When new blood vessels grow, their walls are immature and they leak blood. This is what causes the damage in Myopic Macular Degeneration. Similar to the mechanism behind the damage in Age-Related Macular Degeneration, Myopic Macular Degeneration occurs when this leaked blood causes tissue damage to the overlying retina. Even if the blood is stopped from leaking further, if it was there long enough, it could have changed the architecture of the retina in such a way that disrupts its proper functioning in that area and can result in central vision loss.

Progression and severity of myopic macular degeneration varies widely among individuals. Some have choroidal neovascularization (CNV) and other complications, others never do. In those who have CNV, recurence is another thing that is not uniform, neither is the frequency of recurrence. Therefore, follow-up and treatments are very different among patients and are determined by the doctor.

So is there anything that can be done to prevent Myopic Macular Degeneration? Well, there are certainly precautions that can be taken in order to take a proactive, preventative approach if you have nearsightedness, high nearsightedness, or degenerative myopia.

Preventative Measures:

• Yearly eye exams with dilation of the pupils to check the integrity of the retina
• Adhere to follow-up schedules recommended by your doctor and take all of their recommendations and advice seriously.
• Some experts say to avoid highly physical activities or sports which could result in a sharp blow or shaking of the head.
• Proper Nutrition, make sure you are giving the cells of the macula and retina the building blocks they need to be as healthy and strong as possible.
• At home monitoring of your central vision with an Amsler Grid as directed by your doctor
• Protecting your eyes (cells of the macula and retina) from the UVA/UVB oxidative damage that can occur in repeated exposure to the sun. Wear proper sun protection/sunglasses.
• Know your warning signs of a retinal detachment, if you see FLASHES of light in your vision or FLOATERS that look like curtains, cobwebs, spots that do not go away and increase in number, go to the eye doctor or ER immediately.

Remember, myopic macular degeneration can happen to young people, it is not an illness that occurs with age. To ensure you have good vision your whole life through, take a proactive approach, find an ophthalmologist or retinal specialist you trust and follow their recommendations to a T. Since much of the treatment is customized to the individual, it is essential you adhere to your recommended  follow-up appointments and to their treatment recommendations. It’s ok to ask them questions to understand how your eyes are doing and also to stay current with the latest treatment options available. Degenerative Myopia is re-surging as a hot topic in research and in regards to preventative care for Myopic Macular Degeneration, the future looks bright!

Dear Ms. G;

Thank you for requesting this topic, I hope I have helped you understand it a little bit better. It is a hard topic to cover since so much still remains unknown but I think it is important to review what we know now about it and educate others who may be searching for similar answers or information. If you have any questions at all, I would be more than happy to answer them. You can contact me directly or comment. You are not alone.

Sincerest Thanks

Cheryl G. Murphy, OD

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