TAKE A LEAP


So, the shortest month of the year will be 24 hours longer. That's all it means... right?   Leap years get us all superstitious. We attach strange meanings to things. We think an extra day makes the year magical. But actually, it all comes down to science.   Yip, it's all thanks to the solar year being 365.2422 days. Not 365. It takes 365.2422 days for the earth to revolve around the sun. That 0.2422 doesn't sound like much, but it adds up if no one does something about it. Over centuries, the seasons will eventually get messed up and everything will move out of alignment. Basically, the world will get even more crazy-mixed-up than it already is.   So, adding an extra day every four years keeps everything in perfect balance. Well, it sorts out the earth's problem of 0.2422. Everything that happens on earth is still crazy-mixed-up – load-shedding, SAA, global politics - but the cosmos can only do so much.   And... end science lesson. Begin history lesson.   The Ancient Greeks decided to have their Olympics on the first day of spring. And because they were jumping events, this day was called Leap Day. And because they were from Athens, legend has it they were called athletes. And because this information comes from the Internet, it must be true?!   Then they decided the Olympics should only happen every four years. Some history books say it's because people needed time to travel to Athens to participate. (Four...
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STARS IN OUR EYES!


Not unlike cartoon characters who have stars circling their heads when they are hurt, we "see stars" when we bump our heads, stand up too quickly or rub our eyes too vigorously. What causes this to happen? The retina at the back of the eye converts light entering the eye into electrical signals which are transmitted to the visual area of the brain where they are perceived as images. Normally the cells in the retina respond to light but sometimes an electrical impulse is triggered in the brain in other ways, and the brain interprets this as specks of light. In effect, the brain is tricked into seeing light that is not present. The phenomenon of experiencing light without light actually entering the eye is known as a phosphene and may come from a variety of sources.   Why does it happen when we bump our heads? The human brain is surrounded by cerebrospinal fluid. Because there is some space around the brain, it is able to move within the skull but is cushioned and protected from injury by this fluid. If, however, we bump our heads with force, the brain may hit the area of the skull where the visual cortex, which processes visual information, is situated. This irritation triggers the nerve cells to discharge electrical impulses which are perceived as spots of light or "stars".   Seeing stars when standing up too quickly is a response which occurs from inside the eye itself rather than from an external source,...
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HOW DOES ARTHRITIS AFFECT THE EYES?


Arthritis is most commonly thought of as inflammation causing swelling and pain in the joints. But the condition can cause problems in other, more unexpected areas of the body, including the eyes. Arthritis is a chronic disease which can affect people of any age, race or gender. Women experience more arthritis-related eye problems than men do. TYPES OF ARTHRITIS There are about 100 different forms of arthritis and related diseases, including rheumatoid arthritis, osteoarthritis, psoriatic arthritis, fibromyalgia and gout. The most common types linked with eye problems are rheumatoid and psoriatic arthritis. Rheumatoid arthritis is an autoimmune disease which attacks the connective tissue lining the joints. This connective tissue is made up mostly of collagen, which is the primary substance of the sclera and cornea of the eye. Psoriatic arthritis is an inflammatory condition which can affect connective tissue.   Juvenile or childhood arthritis, as the name suggests, is an umbrella term to describe the many autoimmune and inflammatory conditions that can occur in children aged 16 or younger. The exact cause is unknown, but it is believed to be related to genetics, certain infections and environmental factors. Although the various types of juvenile arthritis share common characteristics, each type is distinct and has its own special concerns and symptoms. Juvenile arthritis, also called juvenile rheumatoid arthritis or childhood arthritis, can affect many parts of the body, including the eyes. The problems may be caused by the disease itself or by medications the child takes to manage the disease. Children with...
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WHEN GLASSES AREN'T ENOUGH


"When my son's eyes were examined the optometrist found that he had 20/20 vision, but he is still struggling in the classroom."   "My child was found to be shortsighted. Glasses helped her to see more clearly but her teacher reports that her reading is not what it should be   The majority of people are born with the potential for good eyesight, but the ability to interpret and understand what is seen is a learned skill which begins to develop from birth. Visual skills include being able to focus, fixate and use both eyes together in order to be able to process visual information. As well as this, there needs to be coordination between the eyes, the other senses and the brain. Problems in any of these areas may manifest as learning problems. Being able to read letters on an eye chart may not guarantee that a child has adequate skills for reading and learning. While glasses may be beneficial for a child with acuity problems, vision therapy may be necessary to address the issue of visual perceptual problems.   Vision therapy is an individualised supervised treatment programme designed to correct visual perceptual deficiencies. The goal of vision therapy is to train the child's brain to use the eyes to receive information effectively, comprehend it quickly and react appropriately. Vision therapy can play an important role in the overall treatment of a child's learning problem. As well as eyestrain, headaches and double vision, children with learning difficulties often experience feelings...
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EYE OPENER


Not only are the eyes the windows to the soul, they also offer a glimpse into the mind and the internal state of the body. The pupils, the black circles in the centre of the eyes, respond to light entering the eyes. In low light they dilate or widen to collect more light, while in bright light they constrict or become smaller. Pupil size is also modulated for reasons other than light, for example thoughts, emotions or mental effort.   Certain prescription medications can cause the pupils to become dilated by interfering with the chemicals that transmit messages from the brain to the eyes, and recreational drugs, such as hallucinogens and stimulants have a similar effect. Neurological conditions of the nerves which go to the eye can interfere with constriction and dilation of the pupils and are often accompanied by other vision symptoms. Injury to the eye may damage the nerves controlling the pupils or the iris, disrupting normal pupillary response. Brain injury as a result of trauma, a stroke or a tumour can cause increased intracranial pressure which can affect the eyes and the reaction of the pupils. Whether it's caused by external or internal factors, pupil dilation is an involuntary nervous system response. In other words, we can't control it.   The visual cortex processes and interprets the images transmitted by the eyes to the brain. A different part of the nervous system, the autonomic nervous system, controls the involuntary functioning of the body, functions over which we have...
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GLAUCOMA – SNEAK THIEF OF SIGHT


World Glaucoma Week, 8th to 14th March, is a joint initiative between the World Glaucoma Association and the World Glaucoma Patient Association to raise awareness of this silent robber of vision. Glaucoma is a group of eye diseases that cause progressive damage of the optic nerve at the point where it leaves the eye to carry visual information to the brain. If left untreated, most types of glaucoma progress without warning nor obvious symptoms towards gradually worsening visual damage and may eventually lead to blindness. Glaucoma is the second most common cause of blindness worldwide. Once incurred, visual damage is generally irreversible, which has led to glaucoma being described as the "silent blinding disease" or the "sneak thief of sight". TYPES OF GLAUCOMA There are several types of glaucoma, the two main kinds being open-angle glaucoma and angle-closure glaucoma. Secondary glaucoma may occur as a complication of other visual disorders, such as cataracts or diabetes, but the vast majority is primary. Less common types of glaucoma include normal-tension glaucoma and pigmentary glaucoma. Some forms of glaucoma may occur in infancy or childhood, and although rare, it can be present at birth. In all types of glaucoma, the optic nerve is gradually damaged. CAUSES OF GLAUCOMA Aqueous humor is a clear fluid which circulates in the inner eye, keeping it firm and nourishing it. It usually flows out of the eye through a channel, but if for any reason drainage is blocked, pressure builds within the eye, gradually damaging the optic nerve....
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THE QUEEN, THE PREZ, AND THOSE UNDERPANTS


Quick disclaimer before we get started. This article will not feature any comments about having "20/20 vision" for the year 2020. My teachers always told us to avoid cliche. And if I play the 2020 card, all their hard work was for nothing.   What we can do is look back on the year that was 2019. And no doubt every person with a Facebook page will name our Rugby World Cup win as their best moment of the year. Some will say they saw it coming all along. Others will say we didn't stand a chance until crunch time came. Whatever your theory, the win was impressive. And if I ask you to name the most memorable image of the year, there's a good chance you'll think of Faf de Klerk and his proudly South African underpants. I'll bet Prince Harry will also put that on his list of 2019 faves.   Speaking of Prince Harry, he and Meghan rejoiced as 2019 was the year of Archie. Their firstborn was greeted with celebration in May. Maybe if he'd been born in November, he would've been christened Prince Faf. (Who knows?!) But either way, his arrival was a great moment for the royal family.   A less great moment for the royals was the time Mister President (the orange American one) messed up the Queen's lawn. The monarch complained that his helicopter scorched the lawns of Buckingham Palace. Quite a way to make an impression when visiting someone's home. Everyone with...
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EYES ON THE ROAD


The end of the year is here at last! Holiday arrangements have been finalised. Christmas shopping has been done. Plans have been made for looking after your home and pets while you are away. Your car has been serviced. Have you checked that your eyes are "roadworthy" for the trip ahead?   We rely on our eyes more than our other senses when driving, as the majority of decisions made while driving are based on information coming in through the eyes. The eyes are constantly in motion, focusing and refocusing on traffic signals and other cars, adjusting to glare from the sun or headlights of oncoming cars, needing to be aware of pedestrians, becoming strained and fatigued on long distances. A complete eye examination will rule out problems that may compromise safe driving and your optometrist will manage problems that are detected before you set out on your journey.   VISION AND DRIVING   Driving requires complex visual skills. Distance acuity, the ability to see clearly at far distances is crucial to safe driving. Have your prescription checked in case there have been changes since your last eye examination. Because the eyes should always be on the road, good peripheral vision is essential to enable the driver to see out of the corner of the eyes anything that is not directly ahead. The driver needs effective depth perception to be able to accurately judge distances, particularly between moving objects, and to safely change lanes. Accommodation is the ability to quickly and...
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MIRROR MIRROR ON THE WALL, WHO IS FAIREST OF THEM ALL?


The wicked queen in the fairy tale "Snow White and the Seven Dwarves" didn't always receive the answer she was hoping to receive when she posed this question. What answer do we expect to hear when we ask related questions? Which gives a fairer reflection of me, the mirror or the camera? Which is more accurate and closer to my actual appearance? Does my reflection in the mirror show me what I really look like? Which image matches the way others see me? The one in the mirror or the one in the photograph? As with the fairy tale queen, the answer is not simple.   While there are similarities in what we see in the mirror and in photographs, there are also some differences. The camera works very much like the human eye in that they both process light and record images, but while the camera is a tool for capturing the images, the visual system makes sense of what is seen. The eye transmits a message to the brain which has the power to process and interpret the information it receives but the camera cannot process or interpret what is captured. Unlike the camera which simply takes a picture, the eyes are constantly receiving a flow of images which need to be processed.   Vision is a dynamic complex process in which the brain uses a combination of information from different sources to generate and make sense of what we see. This includes past experience and expectations as well...
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MOVIE MAGIC


Three-dimensional stereoscopic films are films that enhance the illusion of depth perception. 3D movies have existed in some form or another since the 19th century, but they have had a roller coaster history, alternating between boom and bust. While they would hardly be considered 3D films by today's standards, the first patent for 3D film making was registered in the 1890s. Early 3D movies were typically in black and white, and the 3D movies made in the mid-20th century were generally horror movies. The first major 3D movie in colour, released in 1953, was "The House of Wax" which launched the career of horror movie actor, Vincent Price. The popularity of 3D films waned for some time, until its short-lived revival in the 1980s with the release of "Jaws 3D" and "Amityville 3D". As technology became more sophisticated, the early 2000s saw an explosion of successful 3D films, but it was James Cameron's award-winning "Avatar" that finally established 3D as a medium that is here to stay. Some studios are now converting 2D films into the 3D format.   The creation of the 3D effect in the making of 3D movies mimics the functioning of human vision. Human beings have binocular or stereoscopic vision, each eye seeing a slightly different image. These are fused by the brain into a single three-dimensional image. To create a similar effect, 3D films are captured using two lenses placed side by side about as far apart from each other as the human eyes, recording slightly...
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