Many of us need some form of vision correction. There is a whole fashion industry built around visual defects. Here is a brief letter about the most common visual defects, causes and what you can do about it.
Remember that if you have frequent headaches, it may be because you have a sight problem that needs attention.
Near-sightedness, myopia, is a vision defect in the eye that allows you see well up close but not far away. Myopia is generally caused by genetic factors.
The most common fault is that the focus on distance is reduced, which makes objects in the distance appear blurry depending on how far away it is. This problem can be resolved by wearing suitable concave lenses or glasses. Approximately ten percent of the world population suffers from myopia. In Southeast Asia, almost half of all adults are myopic, and in the old Soviet states they have many very serious cases of near-sightedness.
Measuring myopia with dioptres shows the strength of the proof glass that you need to use to get as sharp an image as possible. If you have over 6.00 dioptres it counts as severe near sightedness and then you run greater risk of suffering from acute eye diseases such as glaucoma and retinal detachment. Most near sighted people also have vitreous floaters or opacities, wandering spots in front of eyes more frequently than others but completely harmless.
The most common reason that you become myopic is genetic. According to some research almost 90 percent of children with myopic parents are affected with the problem themselves. There are even some who believe that myopia may be due to environmental factors and the most common reason would be that the eye is overworked at short distances, for example by reading or watching a computer screen for long periods. However, this is not fully proven.
One can treat myopia either by using lenses, glasses or laser surgery.
Long sightedness, is the most common vision defect in the populations studied. It is estimated that about 80% have a milder form of farsightedness. However, most patients need no glasses for this until middle age, when the lens in the eye becomes more rigid with age and cannot switch between near and distant objects.
Hyperopia is caused because the eye’s refractive system is not strong enough compared to its axial length. Hyperopia can lead to some problems like, headaches and fatigue is common, particularly when working with close up objects.
In some cases of hyperopia, it may be difficult to attain full visual accuracy, even if you have the best glasses. The glasses you would otherwise use for hyperopia are convex, which leads to the user’s eyes looking larger than normal. Hyperopia is often genetic and can evolve with age.
In children with severe hyperopia, it is important that this is treated early and corrected with glasses; otherwise the visual maturation is negatively affected and results in strabismus.
A long-sighted eye becomes slightly oval in shape, thus the eyeball is too short. The image breaks behind the retina instead of being broken just on the retina as a properly functioning eye does. It makes your vision blurry.
A long-sighted person does not need to wear glasses when he or she is such watching TV, but need glasses when reading a book because the person probably keeps the book close to eyes. This results in the image being broken behind the retina.
Hyperopia can sometimes be remedied by laser eye surgery (LASIK), but can also be helped with special concave lenses.
Presbyopia denotes eye difficulties with near vision due to age, and means that the lens is no longer as flexible and therefore more difficult to adapt to different distances. It can be corrected with glasses with positive lenses, known as reading glasses or with laser eye surgery. Presbyopia occurs gradually from about age 40 and by age 50, most people need the help of reading glasses for reading.
The term presbyopia is completely relative as cannot practically put a limit on when presbyopia starts from the biological point of view because the lens changes continuously throughout life. In practice presbyopia starts when the problems are so great that you need to use visual aids to see up close. The farsighted eye is more dependent on an additional near-sighted correction than the myopic, that often to begin with it is able to see up close if the visual aid for distant vision is removed.
In children, the eye can focus continuously and instantly from a very long distance to about four inches in front of the eye. This is possible through the lens of the eye because it is more elastic and thick so that the focus is correct. In the eye of a person in their 60s, the lens has completely solidified.
Presbyopia becomes evident at around 40-45 and increases with time. You may still see well from a distance but it gets increasingly difficult to see up close. The text becomes blurry, the letters flow together, eyes feel strained and you might even get a headache.
If you are moderately near-sighted, it may instead be that you start taking your glasses off when you’re looking close up, since myopia may compensate for age sightedness.
Astigmatism is a refractive error because the cornea is uneven. The uneven cornea allows light that is refracted incorrectly into the eye which causes poor vision and that the victim’s vision is often impaired from both near and afar. This means that astigmatism; in practice is both myopic and hyperopia. There are also those who can see fairly well up close and long range, but not a few meters away. How astigmatism manifests itself depends entirely on how the corneal irregularities look.
Symptoms and Causes
If you feel that you do not see well at all distances, if your eyes feel strained and if you have frequent headaches, you should see an eye care professional to see if you have astigmatism. Astigmatism is usually caused by a faulty growth of the eye but can also be a result of an eye injury or another eye disorder. Astigmatism is often a hereditary eye disease so if one of your parents or grandparents are affected, you should check your eyes.
Astigmatism is corrected easily with the help of glasses or toric contact lenses. These glasses and lenses have been special ground to allow astigmatism sufferers to see well from all distances. Today you can even have laser eye surgery for getting rid of astigmatism.