9 years ago
Thursday, July 30, 2009
Protect and moiturize your skin!
Im sure that most of us know what is body lotion or moisturizer right? hmm... These two weeks are the most busiest weeks in this semester i guess... everyday have to burn mid night oil and this actually hurts our skin the most! Usually i will apply some body lotion before sleep. But now, i seldom. That's because i myself also dont even have the time to sleep!! Where comes the time to apply body lotion and stuff like that?? And the result is, my skin is vry dry now... haiz... poor skin.. So, people!! Please protect your skin especially girls!! Lol..
For those that apply body lotion or skin moisturizer, have u ever curious about the ingredients inside the liquid thing that able to make your skin looks fresh and moisturized? For me, i had never until now... That's y im going to find that out and also share with all of you here...
Lotion is actually a low medium in viscosity material to apply to unbroken skin. Usually lotion contains chemical such as cetearyl alcohol to keep the emulsion of oil and water together. Other than that, fragrances, preservatives and dyes are usually added in also to the lotion to make them more easily acceptable by users.
Other than mosturized the skin, lotion also have other useness in medication sector. It can use as antiseptic, antibiotic, anti-acne agents and also anti-itching agents. Here, i will choose one agents to talk about. The material that cause the lotion to be anti-itching is calamine. Inside calamine, there are zinc oxide and about 0.5% of iron (III) oxide. It can use to treat condition such as sunburn, chicken pox, insects bites and also rashes.
Most of the time, when we look at the ingredients inside, the thing that we concern about the most is, will the ingredients bring harm to us or not? Actually, it should be consider safe to use. Because the cream or lotion have to penetrate through your skin and moisturized the skin. If it is dangerous or harmful, sure there will be some effect shown or some reports being reported and thus i dont think so many of us are using the lotion now...
Although most of the lotion available should be safe to be use, there are still some lotion that we should take note about. Lotion will only provide long term effects if there are some natural ingredients. Avoid some artificial ingredients such as alcohols, mineral oil and the synthetic derivative of useful coconut oil, dioxane. These products had actually been recommended by all skin specialist around the world and should not appear in the lotion as some of them will cause skin cancer. Thus, please be careful when selecting your own choice of lotion. For alcohols, they may appear in the lotion in fragrances form. They are harmful as they might also cause skin cancer and also other skin problems.
Thus, please be careful when choosing your lotion products while protect and moisturized your skin!! Use it safe and use it well for yourself. ^^
Reference:
1) http://en.wikipedia.org/wiki/Body_lotion
2) http://ezinearticles.com/?Are-You-Rubbing-Chemicals-on-Your-Body-With-Body-Creams and-Lotion?&id=1421026
3) http://en.wikipedia.org/wiki/Calamine
4) http://ezinearticles.com/?Benefits-of-Using-Body-Lotion-and-Creams&id=1353570
Wednesday, July 29, 2009
the "food" provided for our food~~
Everyday, we take in different kind of food as our energy source. But, what is the energy source for our food?? Well, some may say that its sunlight... But other than that? what else?? The answer is fertilizers!
Fertilizer adds nutrients and texture to soil that needs to support trees, vegetables, herbs, shrubs, and flowers. The different types of fertilizer depend on whether your soil is acidic, alkaline, sandy, clay, rocky, weak, or rich. Basically, fertilizers may divide into two major types of chemical and organic fertilizers, those that help fruit versus leaves, and those that feed specific plants or improve the overall quality of soil. Here, i will only introduce chemical fertilizers to all of you.
For chemical fertilizers, as what its name tells, are all made up of chemicals. They are specially designed and are mainly made of nitrogen, phosphorus and potassium. The amount of nitrogen will encourage growth of stems and leaves by promoting protein and chlorophyll. Flowers, larger fruits, and healthier roots and tubers will result from the adding of phosphorus. Phosphorus also helps the plants to resist certain diseases. For potassium, it will helps by thickens stems and leaves by fostering protein development. This means that to meet variable demand of the plants, different NPK ratio would be needed more by plants such as vegetables than roses or an orange tree would. NPK ratio is the ratio of nitrogen, phosphorus and potassium in different concentration.
Different plants will require different pH levels. If you need to nudge your soil's pH toward the acidic side, you could use inorganic or chemical fertilizer such as aluminium sulfate or ammonium sulfate. Lime changes soil chemistry to make it more alkaline. Sometimes blood meal or other organic matter can also affect acid levels in the soil.
On the other hand, do chemical fertilizers effect our health? Or do they bring any side effects to us?? According to what i've got from the internet, there are variety of answers available to this.
Usually, the risks of taking chemical fertilizer is that the chemicals might be absorbed by the plants and being taken by us indirectly. Other than that, the plants might also absorbed the chemicals through the polluted underground water which will cause side effects of blue-baby syndrome. Pregnant women might have higher chances to miscarriage. Beside that, some fertilizers even contains heavy metals such as lead, mercury and cadmium which may cause lung and kidney damage if consume in large amount.
Thus, its always better to choose organic fertilizers for our plants or for the food that we are going to consume. People! Support organic!! =)
Reference:
1) http://www.wisegeek.com/what-are-the-different-types-of-fertilizer.htm
2) http://www.landscape-and-garden.com/garden-soil/fertilizer-types.aspx
3) http://wiki.answers.com/Q/What_are_effects_of_chemical_fertilizers_on_human_health
Sunday, July 26, 2009
Save your eyes for those long period sitting in air-cons room!!!
Do u always stay in air-condition room?? Who doesnt always stay in air-conditon room or stay in front of computer for a long time?? I think most people does that right?? For me, im experiencing both of them everyday and also over wearing contact lens everyday. So end up i got a problem, my eyes are very dry!!! Actually most of the people nowadays are experiencing eyes problems and there are more and more ways of improving the problems or treat the problems. For example, eye drop!! Sometimes, some people don't actually know what is the function of an eye drop. Or some people just simply put a few drops of eye drop on their eyes when they feel less comfortable. This is actually very dangerous because there might be a risk for the person to get blind!! Thus, its better to make a consultation at eye doctors before simply get an eye drop. Basically, only few eye problems need an eye drop. These include,
# dryness
# itching
# swelling
# redness
# soreness
# mattering (eye goop)
# allergies or infection
Each type of these eye problems have their specific eye drops. Thus, be alert with the eye drops you are using and also your eye problem to prevent any risks.
Eye drops today mainly have 2 types, with or without preservative. But it is better to use those without preservative because its actually reducing the natural function of your cornea!! Thus, there are less preservative eye drops selling in the market or been using. Here, im only going to talk abt eye drops for dry eyes.
Actually dry eyes is the reduction in the number of conjunctival goblet cells on the surface of the eye. Eye drops therefore work to try and restore this balance in electrolytes as well as moisturizing and lubricating the eyes. Artificial tears or eye drops usually are the first line of treatment for dry eyes. While mild cases require application of lubricant drops four times a day, severe cases require more aggressive treatment, such as ten to twelve times a day. Thicker artificial tears can be used in severe cases, although these may temporarily blur vision.
For more severe cases of dry eye, in which the cornea is inflamed, anti-inflammatory agents are sometimes prescribed. Topical steroids (in eye drops) are safe for short-term use, to combat inflammation, but can cause side-effects when used for a long time. There is also another treatment which is called punctal occlusion. It is a procedure where tiny plugs are used to slow the rate of drainage of tears from the eye into the nose. This is usually for those forms of very dry eyes.
There are few active ingredients in eye drop. An artificial tear inserted that contains hydroxypropyl cellulose, which is one of it, can be used safely every morning. Another ingredient is benzalkoniun chloride. This is an ingredient that will produce allergic reaction for long-term continuous usage. Beside that, higher concentration of this also will cause the denature of corneal protein or punctures of the corneal epithelium. Thus they are normally in a very small concentration.
We know that most of the things will bring us harm if we overdose or over used that. Same goes to eye drop here. The over using of eye drop will give unpleasant side effects, and include vomiting, troubled breathing, and back pain. On the other hand, artificial tears do not contain the same ingredients found in prescription eye drops that can be harmful if overused. Therefore, it is much safer to use artificial tears repeatedly. And for the preservative-free artificial tears, there is almost no risk of overuse!! Its a good news for us.
In conclusion, please be careful with the products you are using for this will affect your sightness, the most important part of your body!! Also, please consult an eye doctor before you use an eye drop for safety purpose. And now, i can enjoy my active lifestyle with no worries of my eyes being dry and uncomfortable! Whee!!
Reference:
1) http://www.dry-eyes.co.uk/acatalog/Can_eye_drops_help.html
2) http://www.allaboutvision.com/buysmart/eye-drops.htm
3) http://www.drugs.com/pdr/genteal-eye-drops.html
4) http://www.docshop.com/2007/09/25/overusing-eye-drops-not-a-pretty-sight/
# dryness
# itching
# swelling
# redness
# soreness
# mattering (eye goop)
# allergies or infection
Each type of these eye problems have their specific eye drops. Thus, be alert with the eye drops you are using and also your eye problem to prevent any risks.
Eye drops today mainly have 2 types, with or without preservative. But it is better to use those without preservative because its actually reducing the natural function of your cornea!! Thus, there are less preservative eye drops selling in the market or been using. Here, im only going to talk abt eye drops for dry eyes.
Actually dry eyes is the reduction in the number of conjunctival goblet cells on the surface of the eye. Eye drops therefore work to try and restore this balance in electrolytes as well as moisturizing and lubricating the eyes. Artificial tears or eye drops usually are the first line of treatment for dry eyes. While mild cases require application of lubricant drops four times a day, severe cases require more aggressive treatment, such as ten to twelve times a day. Thicker artificial tears can be used in severe cases, although these may temporarily blur vision.
For more severe cases of dry eye, in which the cornea is inflamed, anti-inflammatory agents are sometimes prescribed. Topical steroids (in eye drops) are safe for short-term use, to combat inflammation, but can cause side-effects when used for a long time. There is also another treatment which is called punctal occlusion. It is a procedure where tiny plugs are used to slow the rate of drainage of tears from the eye into the nose. This is usually for those forms of very dry eyes.
There are few active ingredients in eye drop. An artificial tear inserted that contains hydroxypropyl cellulose, which is one of it, can be used safely every morning. Another ingredient is benzalkoniun chloride. This is an ingredient that will produce allergic reaction for long-term continuous usage. Beside that, higher concentration of this also will cause the denature of corneal protein or punctures of the corneal epithelium. Thus they are normally in a very small concentration.
We know that most of the things will bring us harm if we overdose or over used that. Same goes to eye drop here. The over using of eye drop will give unpleasant side effects, and include vomiting, troubled breathing, and back pain. On the other hand, artificial tears do not contain the same ingredients found in prescription eye drops that can be harmful if overused. Therefore, it is much safer to use artificial tears repeatedly. And for the preservative-free artificial tears, there is almost no risk of overuse!! Its a good news for us.
In conclusion, please be careful with the products you are using for this will affect your sightness, the most important part of your body!! Also, please consult an eye doctor before you use an eye drop for safety purpose. And now, i can enjoy my active lifestyle with no worries of my eyes being dry and uncomfortable! Whee!!
Reference:
1) http://www.dry-eyes.co.uk/acatalog/Can_eye_drops_help.html
2) http://www.allaboutvision.com/buysmart/eye-drops.htm
3) http://www.drugs.com/pdr/genteal-eye-drops.html
4) http://www.docshop.com/2007/09/25/overusing-eye-drops-not-a-pretty-sight/
Sunday, July 19, 2009
speak with confidence?? or speak with dangers hiding inside??
Please don't get mistaken by the title of this post ya... Its not about how to speak better. Its actually a sharing of information about mouth rinse or mouthwash...
Everyday, we have to deal with a lot of people. Even a simple conversation of just saying hi and bye also we have to open our mouth. Sometimes we may have a bad breath due to several reasons. It will be shameful for the person with bad breath or awkward for the person who is listening. It happens frequently around us everyday. Thus, mouth rinse was invented!!! for the benefit of those people with bad breath and dental problems...
Mouth rinse actually has a long history recorded. It is firstly successfully produced at 1960s where the main effective ingredients, chlorhexidine, is added into the mouth rinse solution. Chlorhexidine is actually a chemical antiseptic which is designed to reduce dental plague and oral bacteria. It can thus improve bad breath. The effectiveness of chlorhexidine is that it can successfully adheres to the surfaces of the mouth and thus remains its present for several hours. In fact, the reference for mouth rinse had actually been noticed back to 2700B.C. in the chinese medicine. Over years and years of inventing and improving, finally it had comes to the products that we have it for today.
Today, we have many types and brands of mouth rinse as more and more people are paying more attention to their breath and oral care. But overall, they can be conclude into two types, cosmetic, therapeutic rinses and a combination of both. So those mouth rinse that we are using daily are belongs to which types?
According to the information of University of Maryland medical center, cosmetic rinses are those sold as over-the-counter products. Cosmetic rinses help to remove oral debris before and after brushing, temporarily suppress bad breath, diminish bacteria in the mouth and also refresh the mouth with a pleasant taste. While for the therapeutic rinses, they have the same functions as cosmetic rinses with a few extra functions. These include in the therapeutic rinses, they have added an active ingredients that helps to protect against some dental diseases into the mouth rinse. Also, these therapeutic rinses had been regulated by US Food and Drugs Administration (FDA) and are voluntarily approved by American Dental Association (ADA). All of these rinses claim that they are effective in reducing the build up of dental plaque and the associated of the severity of gingitvitis, an inflammation of the gum, in addition to fight bad breath.
Yet, most of the dentist are skeptical about the value of these mouth-rinsing products and these products should be used with caution.Although mouth rinse may give us fresh breath, it may brings harm to some people too. This is because the mouth rinse may be masking the symptoms of oral health condition or diseases as the bad breath we have sometimes maybe an alert of our oral health condition indicating somewhere is wrong. Thus, dentists will tell us that it is better to not use the mouth rinse.
Beside that, there are researches and experiments that suggests that rinsing with mouth rinse do bring side effect to us. In most antiseptic mouth wash which is the over the counter products, there will be a high level of alcohols in it of about 18% to 26% depending on the types of mouth rinse. This range of alcohol may produce a burning sensation in cheeks, gums and teeth. It will also caused intoxication if used excessively or swallowed or used by children. For children, even a small dose also potentially be lethal. For those prescribed mouth rinses with higher alcohol level inside, several side effects will possibly be happen. This include ulcers, root sensitivity, soreness, numbness, change in taste sensation and few more. There was a report published by Dental Journal of Australia in January 2009 concluded that there are sufficient effidence that alcohol containing mouth rinse will contribute to the risk of oral cancer!!!! But later, it had been disputed by Yinka Ebo of Cancer Research UK concluding that there are still not enough evidence in showing the claim above. Whether it is true or not, i think all of us can maybe spend a minute or two to sit down and think about this question because afterall, we are the one who will be effected.
Some people will wonder, what is the ingredients in this amazing rinse that provide the function of cleansing our mouth?? Basically there are five types of components that are essential in the mouth rinse. They are an active bacteria-fighting ingredients such as quaternary ammonium compounds, boric and benzoic acid. Example of these are cetylpyridinium chloride and hexetidine. Other than that, these essential compounds include phenolic compounds such as methyl salicylate and thymol, a flavouring agent such as saccharin and glycerin, astringents like zinc chloride to provide a pleasant-tasting sensation and shrink tissues and finally ethyl alcohol, ranging from 18 to 26 percent; and water.
We can see that most mouth rinse do contain alcohol which will make the periodantal diseases getting worse!!!The more alcohol contains in mouth rinse, the more sloughing it will be and this will provide food for the bacteria, leading to higher contents of bacteria in our mouth. This will increase the sulphur levels of bad breath!! Thus, try to avoid alcohol based mouth rinses. Some mouth rinse also contain buffers to reduce acidity, dissolve mucous films and alleviate soft tissue pain. Anticavity rinses usually contain 0.05 percent sodium fluoride, or 0.1 percent stannous fluoride, as approved by the FDA. The active ingredients in mouth rinse can vary. However, all the studies, clearly establish and acknowledge that Chlorhexidine remains the most effective mouthwash.
So, here is what mouth rinse looks like and the information i have about it. Hope that it will roughly give u an idea of how it is. Whether to use it or not, its totally up to you... Thanks for enjoying this post if it does helps you although its bit lengthy =)
References:
1)http://en.wikipedia.org/wiki/Mouthwash
2)http://www.dentalgentlecare.com/mouthrinses.htm#What%20are%20the%20differences%20in%20rinses
3)http://www.umm.edu/oralhealth/rinse.htm
4)http://en.wikipedia.org/wiki/Listerine
Everyday, we have to deal with a lot of people. Even a simple conversation of just saying hi and bye also we have to open our mouth. Sometimes we may have a bad breath due to several reasons. It will be shameful for the person with bad breath or awkward for the person who is listening. It happens frequently around us everyday. Thus, mouth rinse was invented!!! for the benefit of those people with bad breath and dental problems...
Mouth rinse actually has a long history recorded. It is firstly successfully produced at 1960s where the main effective ingredients, chlorhexidine, is added into the mouth rinse solution. Chlorhexidine is actually a chemical antiseptic which is designed to reduce dental plague and oral bacteria. It can thus improve bad breath. The effectiveness of chlorhexidine is that it can successfully adheres to the surfaces of the mouth and thus remains its present for several hours. In fact, the reference for mouth rinse had actually been noticed back to 2700B.C. in the chinese medicine. Over years and years of inventing and improving, finally it had comes to the products that we have it for today.
Today, we have many types and brands of mouth rinse as more and more people are paying more attention to their breath and oral care. But overall, they can be conclude into two types, cosmetic, therapeutic rinses and a combination of both. So those mouth rinse that we are using daily are belongs to which types?
According to the information of University of Maryland medical center, cosmetic rinses are those sold as over-the-counter products. Cosmetic rinses help to remove oral debris before and after brushing, temporarily suppress bad breath, diminish bacteria in the mouth and also refresh the mouth with a pleasant taste. While for the therapeutic rinses, they have the same functions as cosmetic rinses with a few extra functions. These include in the therapeutic rinses, they have added an active ingredients that helps to protect against some dental diseases into the mouth rinse. Also, these therapeutic rinses had been regulated by US Food and Drugs Administration (FDA) and are voluntarily approved by American Dental Association (ADA). All of these rinses claim that they are effective in reducing the build up of dental plaque and the associated of the severity of gingitvitis, an inflammation of the gum, in addition to fight bad breath.
Yet, most of the dentist are skeptical about the value of these mouth-rinsing products and these products should be used with caution.Although mouth rinse may give us fresh breath, it may brings harm to some people too. This is because the mouth rinse may be masking the symptoms of oral health condition or diseases as the bad breath we have sometimes maybe an alert of our oral health condition indicating somewhere is wrong. Thus, dentists will tell us that it is better to not use the mouth rinse.
Beside that, there are researches and experiments that suggests that rinsing with mouth rinse do bring side effect to us. In most antiseptic mouth wash which is the over the counter products, there will be a high level of alcohols in it of about 18% to 26% depending on the types of mouth rinse. This range of alcohol may produce a burning sensation in cheeks, gums and teeth. It will also caused intoxication if used excessively or swallowed or used by children. For children, even a small dose also potentially be lethal. For those prescribed mouth rinses with higher alcohol level inside, several side effects will possibly be happen. This include ulcers, root sensitivity, soreness, numbness, change in taste sensation and few more. There was a report published by Dental Journal of Australia in January 2009 concluded that there are sufficient effidence that alcohol containing mouth rinse will contribute to the risk of oral cancer!!!! But later, it had been disputed by Yinka Ebo of Cancer Research UK concluding that there are still not enough evidence in showing the claim above. Whether it is true or not, i think all of us can maybe spend a minute or two to sit down and think about this question because afterall, we are the one who will be effected.
Some people will wonder, what is the ingredients in this amazing rinse that provide the function of cleansing our mouth?? Basically there are five types of components that are essential in the mouth rinse. They are an active bacteria-fighting ingredients such as quaternary ammonium compounds, boric and benzoic acid. Example of these are cetylpyridinium chloride and hexetidine. Other than that, these essential compounds include phenolic compounds such as methyl salicylate and thymol, a flavouring agent such as saccharin and glycerin, astringents like zinc chloride to provide a pleasant-tasting sensation and shrink tissues and finally ethyl alcohol, ranging from 18 to 26 percent; and water.
We can see that most mouth rinse do contain alcohol which will make the periodantal diseases getting worse!!!The more alcohol contains in mouth rinse, the more sloughing it will be and this will provide food for the bacteria, leading to higher contents of bacteria in our mouth. This will increase the sulphur levels of bad breath!! Thus, try to avoid alcohol based mouth rinses. Some mouth rinse also contain buffers to reduce acidity, dissolve mucous films and alleviate soft tissue pain. Anticavity rinses usually contain 0.05 percent sodium fluoride, or 0.1 percent stannous fluoride, as approved by the FDA. The active ingredients in mouth rinse can vary. However, all the studies, clearly establish and acknowledge that Chlorhexidine remains the most effective mouthwash.
So, here is what mouth rinse looks like and the information i have about it. Hope that it will roughly give u an idea of how it is. Whether to use it or not, its totally up to you... Thanks for enjoying this post if it does helps you although its bit lengthy =)
References:
1)http://en.wikipedia.org/wiki/Mouthwash
2)http://www.dentalgentlecare.com/mouthrinses.htm#What%20are%20the%20differences%20in%20rinses
3)http://www.umm.edu/oralhealth/rinse.htm
4)http://en.wikipedia.org/wiki/Listerine
Thursday, May 14, 2009
Our Precious "Window"~~
Phew! After whole day of classes and rushing, finally im able to sit in front of my computer and write a blog... What a tiring day... Oh ya, talking about tired, its time for me to take out my contact lens after whole day wearing.. I know i shouldn't been wearing it for 12hours, but i just dont like wearing a specs! Ok, since im here, i'll just share some information about contact lens... Something that i wondered about last time...
Do you ever wonder what kind of plastic is inside the contact lens? Well, maybe you can get a better understanding by telling you the history of contact lens.
The first contact lens is form from heavy blown glass and at a diameter of 18-21mm at the year of 1888. This remained as the only form of contact lens until 1930s when polymethyl methacrylate (PMMA) was introduced and be modified into plastic lens at 1936. This kind of lens is a combination of plastic and glass.
PMMA is actually a polymer of C5H8O2. It is a clear polymer and thus widely use in optical applications. It is also use in making windows as it is more transparent than a glass especially when comes to making a thick window. Thus, PMMA is now widely use to make windows, aquarium and even the clear barrier at the ice rinks also made from PMMA!!
But there is an disadvantage of using PMMA, that is no oxygen can pass through the lenses which will cause a number of side effects. Thus, from 1970s to 1990s, oxygen permeable materials were introduced. These ploymer is called rigid gas permeable (RGP). In 1999, silicone hydrogel was first introduced. This is a highly oxygen permeable lens and later be used to make for daily wear lens and overnight wear lens.
Later, second generation of silicone hydrogel was produced which is a slightly modified molecule. In this second generation of silicone hydrogel, a polar group called Tanaka monomer is added without changing the structure. Example of second generation silicone hydrogel are galyfilcon A which may found in Acuvue Advance, Vistakon and senofilcon A which may found in Acuvue Oasys, Vistakon. Both these polymers are added Tanaka monomer. For Vistakon, they even improved the silicone hydrogel by adding in other molecule to become the internal wetting agent.
Sooner, third generation of silicone hydrogel is launch in the market. Comfilcon A which may found in Biofinity, CooperVision, is the first polymer of third generation of silicone hydrogel. This third generation polymer is made of two siloxy macromers where when they combine can give a very high oxygen permeability. Another type of third generation silicone hydrogel is Enfilcon A where you can find in Avaira and CooperVision. It is natural wetting agent in lens where it contains 46% of water.
There are many types of contact lens in the market. One of the latest type is the lens that allow wearers to be continuous wearing the lens for 30 consecutive days. This is very convenient for wearers that are lazy to deal with contact lens daily. The reasons behind that allows the contact lens to be allocate on our cornea for long time is because it is able to increase the rate of uptake of water and thus the rate of oxygen intake as well as removal of carbon dioxide. This kind of lens has an oxygen permeability up to 6 times higher than the normal contact lens!!
Other than this, there are some other types of contact lens that are made to treat other problems rather than shortsighted only. These include contact lens for
1) longsighted (hyperopia)
2) astigmatism
3) presbyopia
While for astigmatism, people tends to have problems in focusing their view as the image is focused on two separate points in the eye. People with this problems thus have to specially make their "toric" contact lens with different curvatures at the front and back as their lens will have to correct the irregular shaped cornea, so that light passed through can fall at only one point. Since they are more difficult to fit and manufacture, thus the price of this contact lens will be slightly more expensive. There are also monthly disposal contact lens for this.
For presbyopia, it is also called "ageing eye". As what it is called, it normally happens when someone is ageing. It happens that they are losing the ability to shift focus between far and near object. Thus, to treat people with this problems, special correctable bifocal contact lens is needed. They are specially made according to the person's special combination of distance and near vision.
http://www.polymerprocessing.com/polymers/PMMA.html
http://pslc.ws/macrog/kidsmac/pmma.htm
http://www.azom.com/Details.asp?ArticleID=784
http://www.matweb.com/search/DataSheet.aspx?bassnum=O1300&group=General&ckck=1
http://www.siliconehydrogels.org/
http://www.allaboutvision.com/contacts/silicone-hydrogel.htm
http://www.aclens.com/silicone-hydrogel-contact-lenses.asp
http://vision.about.com/od/contactlenses/a/Silicone_Hydrog.htm
http://www.siliconehydrogel.co.uk/
http://www.ncbi.nlm.nih.gov/pubmed/16430436
http://en.wikipedia.org/wiki/Contact_lens
http://jbeyecare.com/Contact_Lenses_Information_01.html
http://www.aclm.org.uk/index.php?url=04_FAQs/default.php&Q=10
Do you ever wonder what kind of plastic is inside the contact lens? Well, maybe you can get a better understanding by telling you the history of contact lens.
The first contact lens is form from heavy blown glass and at a diameter of 18-21mm at the year of 1888. This remained as the only form of contact lens until 1930s when polymethyl methacrylate (PMMA) was introduced and be modified into plastic lens at 1936. This kind of lens is a combination of plastic and glass.
PMMA is actually a polymer of C5H8O2. It is a clear polymer and thus widely use in optical applications. It is also use in making windows as it is more transparent than a glass especially when comes to making a thick window. Thus, PMMA is now widely use to make windows, aquarium and even the clear barrier at the ice rinks also made from PMMA!!
But there is an disadvantage of using PMMA, that is no oxygen can pass through the lenses which will cause a number of side effects. Thus, from 1970s to 1990s, oxygen permeable materials were introduced. These ploymer is called rigid gas permeable (RGP). In 1999, silicone hydrogel was first introduced. This is a highly oxygen permeable lens and later be used to make for daily wear lens and overnight wear lens.
Later, second generation of silicone hydrogel was produced which is a slightly modified molecule. In this second generation of silicone hydrogel, a polar group called Tanaka monomer is added without changing the structure. Example of second generation silicone hydrogel are galyfilcon A which may found in Acuvue Advance, Vistakon and senofilcon A which may found in Acuvue Oasys, Vistakon. Both these polymers are added Tanaka monomer. For Vistakon, they even improved the silicone hydrogel by adding in other molecule to become the internal wetting agent.
Sooner, third generation of silicone hydrogel is launch in the market. Comfilcon A which may found in Biofinity, CooperVision, is the first polymer of third generation of silicone hydrogel. This third generation polymer is made of two siloxy macromers where when they combine can give a very high oxygen permeability. Another type of third generation silicone hydrogel is Enfilcon A where you can find in Avaira and CooperVision. It is natural wetting agent in lens where it contains 46% of water.
There are many types of contact lens in the market. One of the latest type is the lens that allow wearers to be continuous wearing the lens for 30 consecutive days. This is very convenient for wearers that are lazy to deal with contact lens daily. The reasons behind that allows the contact lens to be allocate on our cornea for long time is because it is able to increase the rate of uptake of water and thus the rate of oxygen intake as well as removal of carbon dioxide. This kind of lens has an oxygen permeability up to 6 times higher than the normal contact lens!!
Other than this, there are some other types of contact lens that are made to treat other problems rather than shortsighted only. These include contact lens for
1) longsighted (hyperopia)
2) astigmatism
3) presbyopia
*The picture shown is a cornea contact lens inspector*
Longsighted or hyperopia people can have a better vision at a longer distance. They can be treated with a "plus" prescription available at a wide range of contact lens.While for astigmatism, people tends to have problems in focusing their view as the image is focused on two separate points in the eye. People with this problems thus have to specially make their "toric" contact lens with different curvatures at the front and back as their lens will have to correct the irregular shaped cornea, so that light passed through can fall at only one point. Since they are more difficult to fit and manufacture, thus the price of this contact lens will be slightly more expensive. There are also monthly disposal contact lens for this.
For presbyopia, it is also called "ageing eye". As what it is called, it normally happens when someone is ageing. It happens that they are losing the ability to shift focus between far and near object. Thus, to treat people with this problems, special correctable bifocal contact lens is needed. They are specially made according to the person's special combination of distance and near vision.
http://www.polymerprocessing.com/polymers/PMMA.html
http://pslc.ws/macrog/kidsmac/pmma.htm
http://www.azom.com/Details.asp?ArticleID=784
http://www.matweb.com/search/DataSheet.aspx?bassnum=O1300&group=General&ckck=1
http://www.siliconehydrogels.org/
http://www.allaboutvision.com/contacts/silicone-hydrogel.htm
http://www.aclens.com/silicone-hydrogel-contact-lenses.asp
http://vision.about.com/od/contactlenses/a/Silicone_Hydrog.htm
http://www.siliconehydrogel.co.uk/
http://www.ncbi.nlm.nih.gov/pubmed/16430436
http://en.wikipedia.org/wiki/Contact_lens
http://jbeyecare.com/Contact_Lenses_Information_01.html
http://www.aclm.org.uk/index.php?url=04_FAQs/default.php&Q=10
Friday, May 8, 2009
Welcome to my blog!!
Aloha! Haha... Welcome to my blog here.. Ok, erm... Actually im here just to share with u guys on something that i've notice lately. That is, there are a lot of chemicals around us nowadays!!! Do u notice that? For example, the simplest things that we use everyday, shampoo or cleanser, also consist of many types of chemicals... So we really have to be careful on all these. Nevermind, i would like to share with u all about the knowledge that i have and those that i can find... Enjoy! =)
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