Focus on The Eye

The following article is taken from John Hopkins Health Alert:

If you are age 50 or older, you may be concerned about eventually developing one of the four common eye diseases that affect older people cataracts, glaucoma, age-related macular degeneration, and for those with diabetes diabetic retinopathy. Yet most of us rarely consider the complex process that enables us to see the world around us until our vision is threatened. In this Health Alert, Johns Hopkins explains how the eye works.

The eye is a complex structure that sends nerve impulses to the brain when stimulated by light rays reflected from an object. The brain then processes these impulses to create the perception of vision. The eye is made up of numerous parts that work together to make vision possible. Here’s how the eye works:

Eyeball:

When light enters the eye, it first passes through the cornea, a curved, transparent disk that covers the iris and pupil. The iris is the colored part of the eye, composed of connective tissue and muscle. The pupil is the small black opening in the middle of the eye through which light passes.

When exposed to bright light, muscles in the iris contract to make the pupil smaller and to allow less light to enter the eye. In dim light, these muscles expand, pupil size increases, and more light enters the eye. The sclera — the white of the eye — is a protective layer that connects with the cornea and encases the rest of the eye.

Light passes through the pupil and the lens, a transparent, elastic structure that stretches and contracts to help focus light on the retina. (The cornea does about 75% of the work of focusing light on the retina; the lens does the rest.) The light then passes though the vitreous humor, a transparent, gel-like substance that fills the portion of the eye between the lens and retina.

Finally, light reaches the retina, a layer of nerves lining the rear of the eye. The retina senses the characteristics of the light and converts such elements as color, shape, and brightness into electrical impulses that are sent to the brain through a collection of nerve fibers called the optic nerve.

The macula, the important central part of the retina, is located close to the site where the optic nerve connects with the eye. The macula is densely packed with cells called cones, which are critical for seeing color and bright images. (Other cells, called rods, are dispersed in different areas of the retina and respond more strongly to dim light.) The macula is also responsible for detailed visual acuity (needed for activities like reading) as well as for viewing images in the center of the visual field, rather than the periphery.

Where Can You Buy the Cheapest Contact Lenses Online?

When looking for the cheapest contact lenses online you also need to consider how much compromise you are willing to make in regards to quality.  After all, you might find some really cheap contacts but if they give your eyes discomfort or dry them out all of the time it’s simply not worth it.

It’s amazing how much prices will vary from place to place even on the most common contact lenses.  There are many discount contact sites that offer some reduced prices on contacts that would cost a lot more at your eye doctors office.  All you need is a prescription from your visit to the doctor and keep that information.  When you order the lenses online you will have to enter your prescription from your eye exam and the website will actually check with your eye doctor’s office to make sure you really do have a prescription.  This is also helpful because they will make sure you entered your prescription information properly.

Websites like Lensmart and Justlenses.com have cropped up recently, but if you want to buy from a company that has been around for a while you might want to go with 1-800-Contacts begin_of_the_skype_highlighting              1-800-Contacts      end_of_the_skype_highlighting.  They actually have a price match guarantee as well.  Remember, price should not be your only criteria when choosing a place to buy contacts from, so be sure to read some good reviews about the company before you make the purchase.

Buying contacts online is a much cheaper alternative to buying them from the eye doctor’s office, but they may not always recommend this.  Often they will want you to buy from them so they make more money.  But don’t let them dissuade you from getting them online, as they are the exactly same contacts you would buy from them.  They are just a lot cheaper.

So where do you get the cheapest contacts online? I have done the work for you and compared prices from the top contacts lens websites online. Check out where to buy the cheapest contact lenses here.

Article Source: http://EzineArticles.com/?expert=Philip_Richards

Prescription Ski Goggles

I am currently chilling out in Vermont, USA and today we saw snow for the second time in a few weeks. Its not settled on the lower ground yet but it can be seen clearly up in the mountians.

This can only mean one thing…… It’s almost time to dust off your ski’s and snowboards and hit the mountain.

Source: Wikimedia

I love boarding and when I first went struggled immensly with finding some decent ski goggles to fit over my glasses frames. I did eventually find a new pair but after a few hours riding they still made my glasses digg uncomfortably into my nose.

Then a friend put me onto the idea of using prescription ski goggles. I can honestly say this is a fanastic solution. It sure beats being blind on the hill!

Prescription ski goggles can be purchased at a very expensive price for your exact prescription. However there is a much more affordable option where you can purchases googles for a range of prescriptions normally in .5 steps.

My last purchase of Goggles was as simple as looking up the numbers and hitting the purchase button.

In many cases your favorite brands can be found with modified lenses and you can get all the benefits or normal ski masks.

Make sure you bring glasses to the hill though…. Otherwise you will have to wear the Googles all the way home!

snellen eye chart

The Snellen eye chart is that standard eye chart that many of us are all used to seeing when we go for an eye test.

It was designed by a Dutch ophthalmologist who was named Herman Snellen at some point in the 1860s.

There are some other types of commonly used charts such as the Landolt C, and the Lea test but they all do roughly the same thing.

Instructions for printing and using this chart can be found over at it’s source Disabled World.com.

If you need glasses then we always recommend that you purchase for the best prices online. The GlassesEtc banner below allows you access to some great discounts on designer glasses.

Vitamins for Eyesight

Keeping your body in good health is something I am sure you try and do. But how often do you think about your eyes?

Your eyes need to stay healthy too and there are some things that you can do to help this. This includes Exercises to Improve Eyesight and probably most importantly including the correct foods in your diet to keep your eyes operating at top performance.

Source: Wikimedia

People used to always joke that carrots could help you see in the dark. This probably isn’t true but like many vegetables they contain moisture and a whole host of vitamins and minerals that can help eyesight.

The 3 main vitamins believed to be needed by the eyes are:

Vitamin A (also called Retinol)- This is thought to stop you from getting Night Blindness and Xerophthalmia.

Vitamin B2 (also called Riboflavin)- This is essential for the overall health of your eyes.

Niacin (also called nictonic acid or Vitamin B3)- This is needed to help Vitamin B2 function properly.

So where can you get these vitamins?

Vitamin A is actually only found in foods that have originated from animals. However many vegetables contain cartenoids which is a compound that the body can break down into Vitamin A. This means that raw carrots are one of the best sources, hence the legend. Also calfs liver, spinach and leafy veg are great.

Vitamin B2 can be found in high levels in organ meats, cheeses, egg yolks, milk, wild rice, almonds,  whole grains, soybeans, spinach, mushrooms, and chicken. It is also often added to cereals and flour.

Niacin can be found in many foods including organ meats, chicken, beef, tuna, salmon, milk, eggs. Also Carrots, leafy veg, dates, sweet potatoes and avocadoes, nuts wholegrains mushrooms and brewers yeast.

Luckily many of these foods are essential in a healthy diet anyway so it isn’t too much trouble to keep the diet well adjusted enough to take care of your eyes too.

History of Eyeglasses

I always thought that glasses were a fairly modern thing but whilst doing some research I found out that they are much older than I imagined.

Who invented the first wearable glasses?

No body is actually sure of the exact time, date and inventor of glasses but typically Salvino D’Armate is credited with inventing the first eye glasses that were worn. This is thought to have been around 1284.

The earliest image actually depicting a pair of glasses was a portaint of the cardinal Hugh de Provence by Tomaso da Modena in 1352.

There are many other rumors and theories. Here are some of them:

In 1676 a professor at the University of Pisa named Francesco Redi wrote saying that he had in his possession a manuscript from 1289 in which author complained that he would not be able to read or write if glasses had not been recently invented.

Francesco Redi also had a sermon record that was given in 1305. A Dominican monk who’s name was Fra Giordano da Rivalto, said that eye glasses had been invented less than twenty years previous. He also claimed t have met the inventor.

Based on this Francesco Redi also credited credited another Dominican monk who was called Fra Alessandro da Spina of Pisa. He said that Alessandro had reinvented eye glasses because the original inventor had kept them a secret. This claim is contained in da Spina’s obituary record.

Othe possibly legendary, or should we say possible fake stories, credit a man called Roger Bacon.
Bacon is recorded to have made one of the first officially recorded references to the magnifying properties of lenses in 1262. However this is much predated in 1201 in Alhazen’s Book of Optics.

All this means that the exact date and inventor will never be known. It is however almost certain that they were invented in Italy between 1280-1300.

As you know Glasses have really come a long way. Now glasses wearers like myself are lucky to have access to countless styles, hard wearing lenses and frames and many other great features.

FUN FACT: Bifocals were invented in 1784 by the famous scientist Benjamin Franklin. He suffered from myopia and presbyopia and invented bifocals so that he did not have to keep switching glasses.

Image and Information Source: Wikipedia

How Does Laser Eye Surgery Work?

If you have problems with your vision then I am sure you have considered Laser Eye Surgery. I am sure you have heard many great stories and testimonies but you may just be wondering….. How Does Laser Eye Surgery Work?

Before you can understand what the laser in this surgery is actually doing your should first understand why many eye disorders happen. Eye disorders such as nearsightedness, farsightedness, and astigmatism are caused by things known as refractive errors. Refractive errors occur when the cornea is miss shaped. If you need to know, the cornea is the outer transparent membrane of the eye, through which late enters the eye.

So the basic and quick answer to the question “how does laser eye surgery work?” is that it reshapes the abnormally shaped cornea to give you normal or nearer to normal vision.

The laser is known as an Eximer laser and applies your prescription to your cornea. The reshaping process is known as Photoablation. This process involves a highly accurate ultraviolet beam of light stimulating molecules of your cornea until the targeted tissue breaks up and vaporizes.

Obviously different eye disorders require different surgical treatments with tissue being removed from different areas of the cornea to create the correct shape. Nearsightedness surgety removes tissue from the center of the cornea. Farsightedness surgery removes tissue from the edges of the cornea. Astigmatism surgery targets the uneven area. These surgeries effective make your cornea more or less concaved to redirect the light in a correct manner.
These surgeries sound amazing high tech (which they are) and dangerous but the technology has moved on so far that most of the work is done automatically by the bundled laser software. The doctors and technicians simply enter your details such as refractive index into the software and everything is worked out to exact accuracy. Obviously a skilled surgeon will input their knowledge and make sure that the procedure will work in the most effective way for you.

Much of the computational work is actually done by the software that comes from the manufacturer of the laser device. Your surgeon (or, in some cases, a technician) enters your “refractive numbers” into the software, which in turn calculates the exact number of pulses required to achieve the desired level of correction. These calculations can be adjusted by the surgeon depending on the specific needs of the patient i.e. the thickness of his or her cornea, etc. These adjustment factors are called nomograms. What the surgeon DOES perform manually are the nomograms and the exact location on the cornea where the laser is to be directed. It is very important that you choose a surgeon that has performed hundreds, or even better, thousands of laser eye procedures.

Always make sure that you choose a highly experienced surgeon and very respected surgery. This is your eyesight and it is worth doing a lot if research prior to making the decision.

What this video to see a 3D Simulation of the surgery.

For further information I suggest you check out Eyes-and-Vision.com.

Exercises to Improve Eyesight

Like everything in life keeping your vision in it’s best condition requires a little work on your part. If you get lazy with your eyes then your eyesight is likely to deteriorate at a much quicker rate than if you do regular exercises to improve eyesight.

I found an amazing book completely free online that can help you do a whole lot of things to keep your eyes in great shape.

So try these exercises to improve eyesight and then visit the link below:

These exercises were adapted from the online resource Strengthening the Eye.

Exercise A

Turn your eyes and stretch them far over to the left.

Exercise A (Cont…)

Then turn your eyes and stretch them far over to the right hand side. Continue the exercise back and forth from right to left at least ten times.

Exercise B

Turn your eyes upward towards the ceiling. Make sure you look as far as you can without raising your head.

Exercise B (Cont…)

Now, without moving your head, lower your eyes. Look down as far as you can. Do this at least 10 times.

Exercise C.—Raise the eyes and look upward towards the left.

Exercise C (Cont…)

Then lower your eyes to the other side, looking downward toward the right. Repeat at least ten times.

These exercises are fairly simple and over time will keep the muscles in the eyes strong and flexible. It won’t necesarily cure your sight completly but should slow your aging of your vision.

Make sure you check out Strengthening the Eye for many more exercises and help to improve your vision.

Ishihara Test For Color blindness

Color Blindness really is one of those things that facinates me. I am not color blind so cannot fully understand it.

As a child I typically thought that color blind people would have trouble with traffic lights!! Stupid me, the red green and amber are always in the same order!!

Anyway the basics of color blindness mean that some people have trouble differentiating between certain colors and tones. Especially Red and Green. Often causing extreme problems with patterns.

If you feel you may be color blind then one of the best ways to see is to take the Ishihara Color Blindness Test.

Here is part of the full test. If you prove positive with this is could be worth talking to your doctor about your potential color blindness.

Look at the patterns below and see what numbers you can see.

Normal Color Vision			Red-Green Color Blind
	Left	Right		Left	Right
Top	25	29	Top	25	Spots
Middle	45	56	Middle	Spots	56
Bottom	6	8	Bottom	Spots	Spots

Check out the Amazon links at the top of this post for a complete color blindness test kit.

Thanks to Toledo-Bend.com for the color blind test used in this page.

Buy Glasses Online

If you wear glasses you know how much of a hassle and financial burden it is to buy new glasses.

I have worn glasses for most of my life and as a child broke countless pairs. This has not changed too much in my adult life.

After a recent glasses breakage I decided to try and buy glasses online. I was shocked at the savings that exist. Some places allow you to get their own brand glasses from as little as $8 and other places allow you to find all the designer glasses and sunglasses that you would find in your local Lens Crafters. Often these are 50% off!

You can find all the standards of lenses from the budget to the highest quality with all the bells and whistles. UV coating, anti-scratch, bifocals, tints and much much more.

One thing that may worry you when you buy glasses online is the fact that they may not e able to 100% see how they look on you. However online store such as GlassesEtc have awesome buyers guide that help you measure up and make sure you get the right size. This is a bit sneaky but you could always head off to your local Lens Crafters or any opticians, try on some frames, jot down the model number and buy the glasses from a discount site.

Once you buy a pair of glasses online there will be no going back…

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