When you begin to lose your eyesight, which happens to most of us at around the age of forty, you have two basic choices: glasses or contact lenses. Both contact lenses and specs have their advantages and disadvantages, so whichever you choose is really a personal decision. However, some individuals have ‘dry eyes’, which means that the tear ducts do not irrigate the eyes as much as normal.
If someone has dry eyes, then wearing glasses will not exacerbate the condition, but if someone with dry eyes chooses to wear contact lenses for personal reasons, the condition can make their lives very uncomfortable.
Some people who wear contacts but have dry eyes will probably experience a discomfort that will lead to the person rubbing their eyes, which will make the condition worse.
There might be medical reasons for the lacrimal ducts not producing enough moisture to lubricate the eyes, but age can be a factor. If you have itchy eyes and are over sixty, it might be in your interests to change from contacts to spectacles.
Some people find it a very hard decision to take. TV personalities and film stars seldom like to be photographed wearing specs. All right, there are not too many of them, but there are hundreds of millions of individuals who look up to their screen idols and copy them blindly.
One of the causes of dry eyes, besides age or personal illness, is environmental conditions. Pollution affects different people in different ways, but tobacco smoke affects most peoples’ eyes, to say nothing of their lungs.
Evaporation is another reason for dry eyes. This sounds strange, because you would think that the water trapped between the eyes and the lenses could not evaporate, but many contact lenses are composed of fifty percent water to make them more flexible and therefore more comfortable.
A warm environment will evaporate water from the lenses and the lenses will endeavor to replenish themselves by sucking water off your eyes – a kind of osmosis. This is a sensible reason for soaking your contact lenses in a solution over night. The solution is there to sterilize the lenses, but it will also permit the lenses to ‘fill up’ again.
Therefore, a possible solution to the difficulty of dry eyes, if evaporation is your difficulty, is to replace your lenses half way through the day. another way of combatting dry eyes if you would like to wear contacts, is to put drops in your eyes each hour.
You can purchase these drops from a chemist in small containers or you can purchase a litre of the solution and refill your droppers yourself. However, a saline solution (salt and water) is just as good as anything and a great deal cheaper.
If none of this works for you then why not just switch to glasses? The trend is to be more open about oneself and part of this trend is to admit your age, wear your wig openly, if that is what you do and be| seen wearing your spectacles.
Owen Jones, the writer of this piece, writes on a number of subjects, but is now involved with Designer Spectacles. If you want to know more, please go over to our website at Spectacles Direct.
Satellite Radio Technology
Wednesday, November 10th, 2010Satellite radio technology is similar to cable or satellite television and it is certainly here to stay. There are several reasons for this: the quality of the transmissions is higher, the quality of the apparatus’s reception is higher and the general coverage of the station, that is to say the so-called satellite’s footprint is much greater too.
This has the effect that if you drive long distances, you will be able to stick with the same channel without having to look for a new one every forty or fifty miles as you have to do with AM or FM radio stations.
In order to reach this quality, the recording and playback speed needs to be around the 384 kbps level. The music tracks are catalogued in a similar way to the MP3 system, which uses names called ID3 tags.
Each station on satellite radio attempts to establish its own identity. A music station may try this by playing music only of one type or from only one period or decade. This means that you may get a satellite radio station called 1970′s Punk music or Twentieth Century Classical Music.
On some stations, the music controller or disc jockey will choose, say, fifty minutes worth of music, will listen to it in order to determine that the quality and the order are correct and then let the computer play it over the airwaves. This leaves ten minutes every hour for the news and then the programme can be replayed automatically.
Satellite transmission uses digital recordings and each channel is encoded on a different frequency. Similarly, each decoder, say, in your car or your home has to recognize and decode each channel separately as well. This coding and decoding is done very quickly, in fact in what is called ‘real time’.
The resulting binary or digital code is then translated into analogue signals so that your speakers can replay it. This process creates sound which is just about of CD quality.
The transmitting satellites are in a geo-stationary orbit at 23,000 miles above the Earth and have a large footprint which is the name given to the area of ground that is capable of receiving their transmissions.
In America, for example, the two fields concentrated on at first were the densely populated east and west coasts in order to maximize possible income. One satellite would be incapable of covering the whole of the United States in that orbit.
In order to receive satellite broadcasts, you will have to use a special antenna on your decoder. This antenna must be capable of picking up L-band broadcasts for it to be of use.
These new antennas are a huge improvement on the parabolic dishes (equivalent to those used for satellite TV) that one used to have to have in order to take advantage of satellite radio technology
Owen Jones, the author of this piece, writes on a variety of subjects, but is currently involved with Bose radio alarm clocks. If you would like to kcurrently more, please visit our website at Bose Digital Radio.
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