What Are Optical Illusions?

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An optical illusion is something that deceives the eye by appearing to be other than it is. They use patterns, colour and light to create the deception.

We have five main senses – sight, hearing, taste, touch and smell – however most information we receive from the world around us comes via our eyes. This might make sight the most important of all the senses, although let us not underestimate our ability hear a cow moo, touch a feather, smell a beautiful rose or taste an hot apple pie.

Vision depends on our eyes to see and on our brain to convert what we see into images.

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When we look at an optical illusion we may think are we seeing things? Are our eyes deceiving us?

An illusion is proof that we don’t always see what we think we do because of the way our brain interprets the image, we are looking at something that confuses our brain.

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To demonstrate, I particularly like this quote from on http://www.archimedes-lab.org:

Unfortunately (or fortunately?), seeing isn’t some kind of direct perception of reality. Atcually, our bairns are cnostanlty itnerperting, corrceting and gviing srtuctrues to the viusal ipnut form our eeys.

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A mirage and a rainbow are not illusions, they are known as optical phenomena. They are events you can see as a result of light from the sun or moon interacting with the atmosphere, clouds, water and dust.

by John Owens – http://www.john@ezidlabels.comhttp://www.ezidlabels.com

What is Diabetic Retinopathy

I have just heard that one of my relatives who has diabetes has just be diagnosed with a vision problem called Diabetic Retinopathy, so I have done some research and here is a short explanation that may help you or someone you know.

Diabetic retinopathy is a complication of diabetes which affects the tiny blood vessels in the light-sensitive tissue called the retina that lines the back of the eye. The retina detects light and converts it to signals sent through the optic nerve to the brain. Diabetic retinopathy can cause the blood vessels to bleed or leak fluid, thereby distorting vision. Without treatment, diabetic retinopathy can cause loss of vision and blindness.

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Diabetes interferes with the body’s ability to use and store sugar. The disease is characterised by too much sugar in the blood, which can cause damage throughout the body. Low vision is one symptom of diabetes, other symptoms include:

  • increased thirst and hunger
  • weight gain or loss
  • fatigue
  • frequent urination
  • skin infections, and wounds that heal slowly

Diabetic retinopathy affects a large percentage of all patients who have had diabetes for 20 years or more. It is also one the leading causes of blindness for people aged 20 to 64 years.

Often diabetic retinopathy may not be detected until vision loss occurs so people with diabetes should get a comprehensive eye examination when diabetes is first diagnosed and then these tests should be repeated on a regular basis. Early diagnosis and treatment can usually prevent severe vision loss.

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Studies have shown that controlling diabetes can slow the onset and worsening of diabetic retinopathy. People who monitor and maintain a normal glucose level are significantly less likely to develop the disease than those who don’t. Good glucose control also reduces the likelihood of developing other health problems including kidney and nerve diseases. Trials have also shown that controlling blood pressure and cholesterol levels and avoiding tobacco can also reduce the risk of vision loss.

There are several therapies that may be used alone or in combination for treating the disease and reducing vision loss, however they are not a cure for the disease. These treatments are:

  • Laser surgery – the heat from a laser is used to seal or destroy the leaking blood vessels in the retina.
  • Medication – several medications are available to be used in the treatment of diabetic retinopathy. These medications are injected into the eye.
  • Vitrectomy – this treatment involves the use of surgical instruments to remove the damaged blood vessels. Removing this material allows light rays to focus on the retina again.

Vision lost caused by diabetic retinopathy is sometimes irreversible. However, early detection, regular monitoring and treatment can reduce the risk of blindness by a significant amount.

Our goal at EZiD is to assist all people living with low vision by simplifying some of the decisions they have to make every day, for more information about how we can help please use this link.

by John Owens – john@ezidlabels.comhttp://www.ezidlabels.com

What is low vision?

I have read two definitions:

  • “Low vision is the term used to refer to a visual impairment that is not correctable through surgery, pharmaceuticals, glasses or contact lenses. It is often characterised by partial sight, such as blurred vision, blind spots or tunnel vision. Low vision can impact people of all ages, but is primarily associated with older adults.”and,
  • “Low vision is ‘not enough vision to do whatever it is you need to do’, which can vary from person to person”.

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Your vision can deteriorate with age; however, vision loss does not have to be an accepted part of growing old. A yearly eye examination by an optometrist or vision specialist can identify potential vision problems before they occur. In my case a simple trip to the optometrist to organise a new pair of reading glasses revealed the fact I have Age Related Macular Degeneration. I still needed the new reading glasses, and I was given a referral to an eye specialist who is now treating my macular disease.

Because of this early diagnosis the specialist has told me “I will have very useful vision for a long time”. I am now 63 and a bit so ‘a long time’ sounds like very good news to me.
Some of the more common causes of low vision include:

Age Related Macular Degeneration (AMD): AMD is the leading cause of vision loss, for example in the USA it accounts for nearly 50% of all low vision cases. It is caused when the macular breaks down which can cause the loss of central vision, please see this link for more information about AMD.

Glaucoma: is the second major cause of low vision and it can occur without warning. For more info about glaucoma please use this link.

Diabetic Retinopathy: Diabetic retinopathy affects blood vessels in the retina at the back of the eye. It is a major cause of blindness and it is the most common cause of vision loss among people with diabetes.

Cataracts: Most of the eye’s lens is made of water and protein, and the protein is arranged in an exact way to keep the lens clear. As we grow older some of the protein may clump together creating a cataract. Over time, it may grow larger and cloud more of the lens, making it harder to see.

Vision is also an important factor in maintaining balance. Since 2011 In the USA the rate of life-threatening injuries after a fall since has nearly doubled when compared to the previous decade.

It is a shock when you discover your vision loss cannot be reversed, however please remember it can be treated. So, organise the professional help that will provide you with the strategies and treatments to keep you active and safe. Also, why not have a look at the low vision aids we have created to assist in some of your most common daily activities, you will find everything you need here: www.ezidlabels.com.

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by John Owens – john@ezidlabels.comwww.ezidlabels.com

 

The Braille Alphabet

Louis Simon Braille (1809 – 1852) was born in Coupvray, France, the fourth child and only son of Simon-René Braille, a saddle and horse tack maker, and his wife Monique.

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When Braille was three years old, he injured one of his eyes while playing with his father’s leather making tools. This resulted in both his eyes becoming infected, and by the time Braille was five, he was completely blind. Although there were few options for blind children his parents wanted Braille to be educated, first at the local village school then via a scholarship to attend the National Institute for Blind Youth in Paris.

This was the first school of its kind to educate blind students using a combination of oral instruction and raised-print books developed by the school’s founder. Braille did well at his studies and became an accomplished musician. And the crude raised-print books gave Braille the idea that a tactile alphabet would allow blind people to read and write.

In 1821, a retired soldier named Charles Barbier visited the school to share his invention called sonography. This was a complicated code used by soldiers to write and decode messages at night, using a system of twelve raised dots, without having to use a light. The army decided the system was too complicated, however Barbier thought the system might assist blind people.

Braille and some of the other students recognised the possibilities of sonography and over the next three years Braille worked to develop a much simpler system using six dots lined up in two columns of three dots each.

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Braille became an apprentice teacher at the school when he was 19 and in 1837 the school published the first book in braille. However, the school did not adopt the system. Nonetheless, by 1850, when tuberculosis forced Louis Braille to retire from teaching, his six-dot method was on its way to widespread acceptance.

Louis Braille died of his illness on January 6, 1852, in Paris, at the age of 43. Today, in most languages, braille is the standard form of communication used by blind people.

“Access to communication in the widest sense is access to knowledge, and that is vitally important for us if we are not to go on being despised or patronised by condescending sighted people. We do not need pity, nor do we need to be reminded that we are vulnerable. We must be treated as equals – and communication is the way we can bring this about.” Louis Braille 1841.

See the EZiD braille label here.

Albrecht von Graefe (1828 – 1870)

Friedrich Wilhelm Ernst Albrecht von Graefe  has become known as the father of modern ophthalmology.

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Albrecht’s father, Carl Ferdinand von Graefe, was a famous German surgeon and a general in the Prussian army. Young von Graefe became an orphan at age 12, however, as a gifted student, he was able to follow in his father’s footsteps by enrolling in medical school at the University of Berlin in 1843 when he was 15. He graduated four years later and then spent most of the next three years travelling across Europe studying and working with some of the leading ophthalmologists of that period.

His experiences allowed von Graefe to return to Berlin where he opened his first clinic in November, 1850. His talent underpinned the rapid growth of this clinic and in the first year he treated nearly 2,000 patients. He treated poor patients for free.

In the search for better ways to diagnose and treat his patients von Graefe designed new instruments including one of the first devices used to measure intraocular pressure. As his skills and knowledge grew he moved to larger clinic and was soon treating over 10,000 patients a year.

In January 1854, at the age of 26, von Graefe published the first issue of his ophthalmologic journal Archiv fur Ophthalmologie. Remarkably this journal is still published today under the title Graefe’s Archive for Clinical and Experimental Ophthalmology. Von Graefe went onto to contribute to other journals, and in 1857 he helped established the Deutsche Ophthalmologische Gesellschaft which was the world’s first ophthalmic society. Today the society sponsors the Graefe medal for achievements in the field of ophthalmology

Recognition of von Graefe’s achievements was also given by the hundreds of students who he trained. In 1857 von Graefe reached the peak of his career when he reported a cure for glaucoma using iridectomy which is a procedure to remove part of the iris.

In 1861 he became engaged to Anna, Countess Knuth. They married in 1862 and went on to have five children. Von Graefe also contracted acute tuberculous pleurisy in 1861. This did not slow him down and his work load continued to grow. Eventually the disease spread to his lungs and throat but he could continue to work by using morphine to control the pain. However, he eventually succumbed to the disease and died on July 20, 1870 at the age of 42, his wife died two years later at the age of 30.

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His image lives on in a statue that was erected by the Berlin Medical Society in 1882 in front of the Charité Hospital, and a Graefe Museum in the Heidelberg eye clinic.

by John Owens – john@ezidlabels.comwww.ezidlabels.com

 

Who Created The Eye Test Chart?

The eye test chart was designed by Herman Snellen (1834 – 1908) in 1862. Herman was a Dutch ophthalmologist and he developed the chart as an aid to measure an individual’s vision.

Snellen earned his medical degree at Utrecht University in the Netherlands in 1858. He specialised in ophthalmology after completing his degree and in 1877 was appointed a professor of ophthalmology at the University. His research was based on causes of low vision including glaucoma and astigmatism (a fault in the shape of the eye’s lens).

Other versions of eye test charts had been developed previously however these charts were never standardised. They used fonts of different sizes and shapes and did not necessarily provide an accurate assessment of a person’s real vision.

The British Army placed a large order for the Snellen chart in 1863, and from there it quickly became the global standard for almost 100 years. It is also the standard on which all more recent eye test chart systems are based.

Snellens’ innovation was to use specially designed characters, known as optotypes, instead of an existing, standard font. The Snellen optotype was based on a 5 x 5 grid and this grid was used to create a limited character set of 9 – 10 letters. The lines were a standard thickness and letters were all the same shape.

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This allowed the chart to be reproduced easily and provide accurate results wherever it was used.

The Snellen chart normally includes eleven lines of block letters. The first line comprises a single large letter, usually the letter E. Each of the following lines have increasing numbers of letters, each progressively smaller in size.

The Snellen eye test determines the visual acuity (clarity of vision) of an individual based on which is the smallest row of letters they can read.

With the traditional Snellen eye chart, the individual who can read the row of letters fourth from the bottom of the chart at 20 feet has 20/20 vision. The next three lines provide a measurement of 20/15, 20/10 and 20/5 vision. Not many individuals have 20/10 or better however many animals do, especially birds of prey, which may have an acuity of 20/5 or even better.

Testing with the Snellen eye chart helps reveal visual problems and symptoms of other medical conditions. However it is only one component of a complete eye examination.

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Images courtesy Wikipedia

by John Owens – john@ezidlabels.com   – www.ezidlabels.com

The Blind Benefactor – Joseph Pulitzer

Joseph Pulitzer was an American newspaper editor and publisher who helped establish the design of contemporary newspapers. However, he is probably better known for posthumously establishing the Pulitzer Prizes (along with William Randolph Hearst). He is also one of the most historic figures to have detached retinas, which eventually lead to him becoming blind at the age of 42.

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Joseph Pulitzer, detail of a portrait by C. de Grimm from The Curio, November 1887.Copyright the Library of Congress, Washington, D.C.

Joseph was born in Hungary then moved to Budapest with his family when his father retired. He tried to join the army at age 17 and was rejected because of his bad eyesight and frail health by the Austrian and British armies and the French Foreign Legion. He then moved to the United States in 1864 as a recruit for the Union Army in the American Civil War. After the war, he moved to New York then to St. Louis where he worked as a deckhand, a hack driver, a grave digger and briefly as a waiter.

His big break came when he joined a railroad company to record land entitlements. This led him to law school and he was admitted to the bar in 1868. He also became an American citizen in 1867. Pulitzer married Kate Davis in 1878 and they had seven children.

Pulitzer’s newspaper publishing efforts combined investigative journalism with publicity stunts which were very popular with his readers. He also introduced entertainment innovations such as comics, sports coverage and women’s fashion coverage into his newspapers which created the journalistic style that is still in use today.

In 1887 failing eyesight and his other illnesses forced Pulitzer to abandon the management of his newspapers. In 1890 he gave up his editorship of them as well however he continued to monitor their editorial policies.

Pulitzer died of heart failure in 1911 at the age of 64 and was buried in New York. in his will Pulitzer endowed the Columbia University School of Journalism which opened 1912. The school now oversees the Pulitzer Prize, an award given to those who excel in journalism, literature, and music. This has been awarded annually since 1917.

Joseph Pulitzer suffered from poor health and bad eyesight most of his life. His eyesight problems were caused by detached retinas in both his eyes. The retina is the light-sensitive layer of tissue that lines the inside of the eye and sends visual messages through the optic nerve to the brain. When the retina detaches, it is lifted or pulled from its normal position, see diagram below. It is caused by inflammation, abnormal blood vessels, diseases such as diabetes or injury. If not promptly treated by surgery, retinal detachment can cause blindness.

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