Bifocal glasses are used to correct vision at two distances—a prescription on top for far away and a different prescription on the bottom for near. Most people think of bifocals as reading glasses for people over forty who lose their ability to focus up close as they age. But children can also need reading glasses.
Many children have not developed sufficient control over their focusing systems, the natural lens inside the eye that keeps images clear, especially up close. Some children lack the ability to sustain sufficient focusing over an extended time period, so after a while print begins to blur. Others can’t make fast focusing shifts from one distance to another, like from the board to their desks, so any time they look away, everything is blurry. Some children have a tendency to over focus, and the additional stress causes eyestrain and headaches. If they over focus too much, the additional tension on the visual system can make the eyes to turn too far inward, causing double vision. Finally, near work at school places much more stress on the visual system than distance viewing, and some young children respond by translating the visual stress into physical and emotional symptoms—back and neck tension, headaches, constriction of their perceptual fields and a reduction in their visual space, a tendency to develop nearsightedness, and avoidance of the reading tasks that are causing the physical and visual discomfort.
Prescribing reading glasses effectively treats many of these problems. A convex plus lens relaxes the child’s focusing system, relieving much of the visual stress. In fact, prescribing a low power plus lens is so effective in keeping children’s visual system comfortable during extended close work at school that they are often called “learning lenses.”
Reading glasses that use a bifocal are a good option for school-aged children who only need the additional correction up close. The bifocal gives them the lens support they need for deskwork but doesn’t change their distance vision. Sometimes vision therapy is also prescribed when the focusing problem is severe enough that additional interventions are also required.
New advances in lenses allow children flexibility in the type of bifocal they choose. Many children still prefer the flat-top bifocal because the line separating the two powers helps them tell exactly where their distance prescription ends and their near prescription starts. However, some children or parents don't like the look of the "line", so for them progressive no-line bifocals are a good option. The lens is made so that the change between prescriptions is so gradual no line appears. Another very popular option is the "half-moon" bifocal. It has the advantage of a clear delineation between powers liked lined bifocals but when the glasses are on the child's face, the bifocal is invisible like progressive lenses.
When bifocals or reading glasses are prescribed, it is important that children wear them for all close work, especially at school and during homework. Sometimes children will only need the bifocals for a few years as they develop control of their focusing system. Others may need the additional near-point support for as long as they are in school and spending a lot of time reading.
Bifocals are an important tool for optometrists when working with children who spend up to eight hours a day using their eyes for reading and school work. By adding an additional lens power for up close, optometrists are able to adjust children’s focusing system to give them better control and eliminate eyestrain, blurred vision, headaches, and fatigue.
From: www.childrensvision.com/bifocals.htm
Friday, July 4, 2008
Transitions bifocals
Q: I had a patient come in today asking for transitions lenses. He wanted the distance to be photochromic, but the seg he wanted to remain clear.
I was curious as to if such a lens was possible with what little I know of the technology, and if it was, does it exist?
A1: The patient probablly had a glass Photo gray ST 28, probably wants same again, but doesn't know the difference between transitions and photo gray. Glass photo gray ST 28's have clear segs.
As to transitions made this way, I don't think there are any available, but since transtions is a dip, lens could be masked in segment area before dipping.
By: chip anderson
A2: segs on glass lenses are not photochromic, not very appealing, cosmeticly. The seg is a different RI from the rest of the lens that was cast from silver halide laden molten glass. This seg "button" is attached and becomes part of the glass lens in a very interesting process. If you ever have a chance to see glass lenses, especially segmented products being produced at a factory, it is worth seeing.
It is still hard for me to understand why anyone would want that type of look....clear or dark segs and all, with all the great PALS out there, why would anyone want a seg line! I just hit 50 and have had to wear glasses for about 3 years now. The folks I grew up with all hit that age where their arms became to short. I am happy to say only one person among my peers bought bifocals....but his next pair will be a PAL, now that he knows that they exist. His ECP never presented the option to him. Beat that.
I do want to clear up one misconception in the prior posting.
Transitions are not produced by dip coating. Transitions Lenses are produced by placing the photochromic package into the front surface of the lens (imbibition technology) or by bonding a photochromic layer (Transbonding) on Trivex, Polycarbonate and 1.67 Hi Index lens materials.
Both Transitions Lens processes are patent protected.
Thus leaving the dip coating (photochromics disolved in a liquid carrier, lens dipped in the solution, allowed to dry then heated to permenantly place the pc chemicals on the surface of the lens) along with cast in place (photochromic package mixed with monomer (just like glass pc process) and cast in desired lens mold design) as the other options to make a lens photochromic.
By : Jim Schafer
I was curious as to if such a lens was possible with what little I know of the technology, and if it was, does it exist?
A1: The patient probablly had a glass Photo gray ST 28, probably wants same again, but doesn't know the difference between transitions and photo gray. Glass photo gray ST 28's have clear segs.
As to transitions made this way, I don't think there are any available, but since transtions is a dip, lens could be masked in segment area before dipping.
By: chip anderson
A2: segs on glass lenses are not photochromic, not very appealing, cosmeticly. The seg is a different RI from the rest of the lens that was cast from silver halide laden molten glass. This seg "button" is attached and becomes part of the glass lens in a very interesting process. If you ever have a chance to see glass lenses, especially segmented products being produced at a factory, it is worth seeing.
It is still hard for me to understand why anyone would want that type of look....clear or dark segs and all, with all the great PALS out there, why would anyone want a seg line! I just hit 50 and have had to wear glasses for about 3 years now. The folks I grew up with all hit that age where their arms became to short. I am happy to say only one person among my peers bought bifocals....but his next pair will be a PAL, now that he knows that they exist. His ECP never presented the option to him. Beat that.
I do want to clear up one misconception in the prior posting.
Transitions are not produced by dip coating. Transitions Lenses are produced by placing the photochromic package into the front surface of the lens (imbibition technology) or by bonding a photochromic layer (Transbonding) on Trivex, Polycarbonate and 1.67 Hi Index lens materials.
Both Transitions Lens processes are patent protected.
Thus leaving the dip coating (photochromics disolved in a liquid carrier, lens dipped in the solution, allowed to dry then heated to permenantly place the pc chemicals on the surface of the lens) along with cast in place (photochromic package mixed with monomer (just like glass pc process) and cast in desired lens mold design) as the other options to make a lens photochromic.
By : Jim Schafer
Bifocals for kids
Executive-style lenses for children are overkill. For one thing, these lenses are often prescribed to reduce accommodative esotropia, which often occurs in highly hyperopic children (who need a high plus power). These lenses are excessively thick, heavy, and limited in material availability.
A FT-35 should provide more than enough width for a child (I can't imagine a child turning his/her gaze out that far to read anything -- it's almost a 40-degree eye rotation). Also, a FT will leave a little temporal vision for seeing the ground in the periphery more easily. It should be pretty easy to get a FT-35 in several materials, including polycarbonate.
As far as progressives for children... I would be tempted to use a short-corridor progressive, myself (and only if cosmetics are a serious issue). Most children wearing bifocals do so because of binocular vision disorders, not because of reduced accommodative amplitudes. This means that children can often see clearly anywhere through the distance, corridor, or near zone of the lens. However, if the child doesn't reach the full power of the near zone the benefits of the lens are not realized. This is exactly why bifocals are positioned so high with children. Progressive lenses, which already require more depression of the eyes while reading, must be positioned several millimeters above the pupil on children. You should also be aware of reduced distance and near utility.
On the other hand, certain "computer" lenses might show more promise for children. I believe there was actually a study conducted to evaluate such lenses for children, although I do not have the results handy. Blended bifocals, fit high, might also be an affordable option.
By Darryl Meister
A FT-35 should provide more than enough width for a child (I can't imagine a child turning his/her gaze out that far to read anything -- it's almost a 40-degree eye rotation). Also, a FT will leave a little temporal vision for seeing the ground in the periphery more easily. It should be pretty easy to get a FT-35 in several materials, including polycarbonate.
As far as progressives for children... I would be tempted to use a short-corridor progressive, myself (and only if cosmetics are a serious issue). Most children wearing bifocals do so because of binocular vision disorders, not because of reduced accommodative amplitudes. This means that children can often see clearly anywhere through the distance, corridor, or near zone of the lens. However, if the child doesn't reach the full power of the near zone the benefits of the lens are not realized. This is exactly why bifocals are positioned so high with children. Progressive lenses, which already require more depression of the eyes while reading, must be positioned several millimeters above the pupil on children. You should also be aware of reduced distance and near utility.
On the other hand, certain "computer" lenses might show more promise for children. I believe there was actually a study conducted to evaluate such lenses for children, although I do not have the results handy. Blended bifocals, fit high, might also be an affordable option.
By Darryl Meister
TIPS ON FITTING BIFOCALS TO CHILDERN
Try fitting E style or large round seg bifocal with segment tops just 1mm below pupil,reason for this high fitting is to ensure that the child does not use upper portion of the lens for close work,and in the event if his/her spectacles get loose.Also use specially designed spectacle frames for very small childern which have loop-end sides thru which a ribbon can be passed and tied at the back of the head to secure spectacles.With hyperactive small childern use frames fitted with bridle.For older childern frames with curl ends serves the purpose well.
If the child does not accept glasses, try experimenting with different positioning of segment tops, keeping in mind that he is required not to look from distance portion of segment for close work.
by SHABBIR KAPASI
If the child does not accept glasses, try experimenting with different positioning of segment tops, keeping in mind that he is required not to look from distance portion of segment for close work.
by SHABBIR KAPASI
Thursday, July 3, 2008
Magnetic Front Connection Reading Glasses
front connect reading glasses are fabulous no more lost glasses. The unique design is perfect for those of us who need glasses handy and don't want to wear the long, it's so easy to keep my glasses where i can get to them quickly. These glasses are lightweight, comfortable and stylish. What a cool idea. i highly recommend these glasses for anyone that needs a little help reading the small.
Monday, June 9, 2008
how to repair scratched glasses lenses
Wearing glasses isn't as popular as it once was since more and more people who need vision correction are choosing contact lens instead. If you have glass eyeglass lenses, they're better than plastic lenses because glass doesn't scratch as easy. However, glass lenses still manage to get scratched. And, it's hard to see through scratched lenses, no matter what the material is.
You might think that the only way to get rid of the scratches is to spend the money for a whole new set of eyeglasses. You can do it this way, or, you can just purchase replacement lenses and reuse your existing frame. Or, as long as your eyeglass prescription is current, you can save even more money by simply repairing the scratched glasses lenses yourself.
How can you do this? There are good quality polishing kits on the market that you can purchase for this purpose. A kit will cost anywhere from ten to twenty dollars, and it works best when it's used for lighter scratches. Lighter scratches are generally acquired from day to day wear. They also are made on the lenses of your glasses if you use a paper towel, or another type of rough cloth or material to clean them with. Whether you have plastic or glass lenses, you should also use a clean, soft towel and a recommended lens cleaner.
Deep scratches are usually caused by rough handling of the glasses, or, by accidents. They cannot be polished out like lighter scratches can. If you have deep scratches in your glasses, then you'll have to visit your local optometrist to see what he or she recommends. Again, replacement lenses will probably be your only option if your glasses lenses have deep scratches on them.
You can check with your local optometrist to find out what type of polishing kit he or she might sell. Or, you can perform a search on the Internet to find out what other kits are available online and the price of each one.
Once you purchase a polishing kit, be sure that you read the manufacturer's directions and follow them in order to achieve the best results. Some polishes won't work if your eyeglasses have a protective coating or a non-glare solution on them.
Basically, though, all you need to do is to make sure that the lenses in your eyeglasses are clean. Then, pour some of the polish onto both sides of each lens. Allow the polish to sit for a specified number of minutes. Then, use the cloth that was included in the kit to buff the lens until all of the polish is removed. The glass should now look clean, clear, and free of lighter scratches!
Usually, you can use a polishing kit as much as you need to in order to keep your glasses lenses free from scratches from then on. Never more will you have to squint to see through scratched glasses!
Finally, in order to best protect your health as well as your vision, you should have your eyes checked by a licensed optometrist every year or two. And, take care of your glasses so you can avoid replacing them before they are due!
Written by K Sprang
From : essortment.com
You might think that the only way to get rid of the scratches is to spend the money for a whole new set of eyeglasses. You can do it this way, or, you can just purchase replacement lenses and reuse your existing frame. Or, as long as your eyeglass prescription is current, you can save even more money by simply repairing the scratched glasses lenses yourself.
How can you do this? There are good quality polishing kits on the market that you can purchase for this purpose. A kit will cost anywhere from ten to twenty dollars, and it works best when it's used for lighter scratches. Lighter scratches are generally acquired from day to day wear. They also are made on the lenses of your glasses if you use a paper towel, or another type of rough cloth or material to clean them with. Whether you have plastic or glass lenses, you should also use a clean, soft towel and a recommended lens cleaner.
Deep scratches are usually caused by rough handling of the glasses, or, by accidents. They cannot be polished out like lighter scratches can. If you have deep scratches in your glasses, then you'll have to visit your local optometrist to see what he or she recommends. Again, replacement lenses will probably be your only option if your glasses lenses have deep scratches on them.
You can check with your local optometrist to find out what type of polishing kit he or she might sell. Or, you can perform a search on the Internet to find out what other kits are available online and the price of each one.
Once you purchase a polishing kit, be sure that you read the manufacturer's directions and follow them in order to achieve the best results. Some polishes won't work if your eyeglasses have a protective coating or a non-glare solution on them.
Basically, though, all you need to do is to make sure that the lenses in your eyeglasses are clean. Then, pour some of the polish onto both sides of each lens. Allow the polish to sit for a specified number of minutes. Then, use the cloth that was included in the kit to buff the lens until all of the polish is removed. The glass should now look clean, clear, and free of lighter scratches!
Usually, you can use a polishing kit as much as you need to in order to keep your glasses lenses free from scratches from then on. Never more will you have to squint to see through scratched glasses!
Finally, in order to best protect your health as well as your vision, you should have your eyes checked by a licensed optometrist every year or two. And, take care of your glasses so you can avoid replacing them before they are due!
Written by K Sprang
From : essortment.com
Sunday, June 8, 2008
How to Polish Scratches Off Glasses
Nothing is more frustrating than getting a new pair of glasses only to find that somehow you have gotten them scratched. Eyeglasses are a large investment and many times need to be kept for years. Finding that a scratch is now permanently in your line of vision, you may be tempted to toss them out, but before you give up, try these steps to remove the scratches from your eyeglasses. Read on to learn more.
Step1
Understand the limits of removing scratches. Unlike other glass or crystal products, buffing will change the strength of the lenses. Deep scratches can be cleaned up but not removed completely and it's possible that minor scratches can become unnoticeable.
Step2
Know exactly what your surface is made of. Check if the surface Is glass or plastic lenses with or without coating. This will make a difference on the approach you take to remove scratches.
Step3
Use a lens cleaner, either from your optometrist or from a CD cleaning kit. This works best to remove minor scratches on eyeglasses.
Step4
Try a metal polish and a soft cloth, rubbing in a circular pattern for about 5 minutes, depending on the severity of the scratches. It may take several applications, so continue to polish until you achieve the results you desire. Rinse the glasses in soapy water to remove any residue when finished.
Step5
Rub on creams made for taking scratches from sports helmets. You can find the cream in most sporting goods stores.
Step6
Drop a small amount of baby oil onto the lenses and rub with a soft cloth. Again, this may take time and works best for minor scratches.
From : ehow.com
Step1
Understand the limits of removing scratches. Unlike other glass or crystal products, buffing will change the strength of the lenses. Deep scratches can be cleaned up but not removed completely and it's possible that minor scratches can become unnoticeable.
Step2
Know exactly what your surface is made of. Check if the surface Is glass or plastic lenses with or without coating. This will make a difference on the approach you take to remove scratches.
Step3
Use a lens cleaner, either from your optometrist or from a CD cleaning kit. This works best to remove minor scratches on eyeglasses.
Step4
Try a metal polish and a soft cloth, rubbing in a circular pattern for about 5 minutes, depending on the severity of the scratches. It may take several applications, so continue to polish until you achieve the results you desire. Rinse the glasses in soapy water to remove any residue when finished.
Step5
Rub on creams made for taking scratches from sports helmets. You can find the cream in most sporting goods stores.
Step6
Drop a small amount of baby oil onto the lenses and rub with a soft cloth. Again, this may take time and works best for minor scratches.
From : ehow.com
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