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Written by Webmaster
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By john mce
 We've all had some fun with optical illusions, staring blankly at pictures for 5 minutes until a rabbit turns into a duck, or a Jackson Pollack style painting slowly morphs into a forest scene, or more often than not nothing happens at all and you've been gazing dumbly at a set of squiggly lines and splodges for God knows how long.
However do these optical illusions have any other value than brief entertainment? Can they be used to improve people's perception?
Primarily we have to define which type of optical illusion we are referring to as there are three; literal optical illusions, physiological illusions and cognitive illusions. The latter plays on unconscious inferences and assumptions about the world that are embedded into our minds and therefore can dictate our perception because of what we expect to see.
Physiological illusions are typified by exposure to excessive stimuli such as bright lights or movement. These cause an imbalance in the viewer's visual channels, resulting in altered observation. Finally, literal optical illusions create images that differ from the actual objects and components that |
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Written by Webmaster
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By Chris Crowe
 LASIK eye surgery is fast becoming an extremely popular solution to vision problems. The first clinical studies took place in the 1990s, and since then it has proved reliable and highly successful. In this respect it is relatively new, though the science behind LASIK surgery has in fact been around for years. Here is a brief guide to the history of this popular procedure.
The process of LASIK surgery involves two steps. First, a flap is created on the cornea to allow the surgeon access to reshape the eye to correct any irregularities on the surface. The reshaping process itself is known as keratomileusis.
The tool used to create the corneal flap was first created during the 1970s by a Colombian doctor called Jose Barraquer. This is a metal tool known as a microkeratome, and effectively uses a blade in the creation of the corneal flap. However, today many LASIK surgery procedures make use of lasers to create the flap rather than the microkeratome. However, some procedures do still use the microkeratome, and this process was the only method for around 40 years |
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Written by Webmaster
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By Chris Crowe
 LASIK eye surgery is now becoming more and more common for anyone who wishes to improve their eyesight. However, PRK surgery, or photorefractive keratectomy, was in the past the most common type of laser surgery performed on the eyes for vision problems and is still used today. Here is a quick guide to the similarities and differences between the two types of surgery.
The Corneal Flap
As you are probably aware, LASIK surgery requires the creation of a corneal flap under which the laser does its job to correct any aberrations in vision. This is one of the main differences between LASIK and PRK, as no flap is created in the PRK procedure.
During PRK surgery, a flap is created by using a blade and then alcohol is used to scrape the flap away from the eye's surface. This means that only the area to be treated will then be exposed. This type of surgery is usually more appropriate for patients who have thinner corneas.
During LASIK the flap is kept as a way to reduce any complications such as the |
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Written by Webmaster
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By Chris Crowe
 Laser eye surgery is a way of improving eyesight, but without aids such as glasses or contact lenses. It is used to correct astigmatism as well as nearsightedness and farsightedness by reshaping the eye's surface using lasers. There are slightly different procedures used during laser eye surgery, and the type for you will depend on your specific sight condition.
Any eye doctor will be able to advise you on which surgery will be safest and most effective. Here is a brief guide to what you can expect from laser eye surgery.
All types of laser eye surgery will make use of a laser to reshape the surface of the eye, and therefore correcting any vision problems you may have. When going through Lasik surgery you will find that an incision is made on the cornea to create a flap. Recovery usually only takes a few days, and your sight should be significantly improved (though there is no guarantee it will be 100% perfect).
When you are thinking of having laser eye surgery of any kind any past medical conditions will |
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By john mce
 Do you squint when reading from your computer screen? Do numbers and letters seem to fade in and out from time to time? Do you find it hard to focus? If so, you are probably experiencing deterioration of your eyesight. Eyes are often neglected by people and eyesight often deteriorates prematurely as a result. Here are a few tips to keeping your eyes healthy for longer.
Stop Smoking
Smoking can be very bad for your eyes. A recent article in Reuters Health Information states that smoking increases the risk of developing cataracts, clouding the lens and impairing vision. If you stop smoking, you have a reduced risk of developing cataracts in later life, but only some of the damage done to your eye by smoking cigarettes is reversible.
A study found that men who quit smoking had a 23% reduced risk of cataract diagnosis and a 28% reduced risk for cataract removal, compared with those who carried on smoking.
Limit Computer Time
Using computers on a daily basis is probably more strenuous on eyes than any other part of the body. The |
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