some doubts regarding eyesight
- Thread starter Rave
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Astigmatism means that the power is on an axis. Regular soft lenses rotate in the eye from time to time. Toric lenses contain your spherical power (if any) and your cylinderical power which is on an axis. Now, if the lens was to rotate in your eye, the axis would change and your vision would get affected depending on how high the astigmatism is. In my case, it gets affected a lot. Toric lenses do end up moving out of place, but rarely. It depends on how good the fit is. They are made in such a way that they do not rotate.
As an Optician I fit Toric contact lenses all the time and yes they have been around for years and are even available in disposable lenses too.
Most Toric contact lenses are weighted (meaning they are thicker on one edge) to prevent the lenses from rotating.
Toric lenses are slightly more complicated to fit as the fit depends not only on the amount of astigmatism, but the shape of the eye too. For example lets say the axis of your cylinder power (astigmatism) is 90 degrees and so the Toric contact lens is ordered so that the weighted edge causes the lens to sit at 90 degrees... well sometimes the shape of the eye can cause the lens to rotate further in one direction... for example 10 degrees.
The lens then has to be ordered with an extra 10 degree compensation so that it sits in the correct place.
It is quite common for a lens to be prescribed using a combination of the sphere and cylindrical power, it is what we call a spherical equivalent and is generally used for milder amounts of astigmatism usually under 1 diopter.
For example if a person has 1 diopter of sphere and 1 diopter of astigmatism, the spherical equivalent is actually 1.5. If you added the full amount of both it would be far too strong and so typically only half of the astigmatism is added to the sphere to determine the contact lens power.
Coming back to the 3D aspect of all this, one has to remember that to see in 3D we must be able to see in a binocular manner, meaning both eyes together as this is how we are able to judge distance and use depth perception. So if one eye is not seeing as clearly, you will have a harder time with 3D glasses too. Of course seeing clearly in general is a factor too
Most Toric contact lenses are weighted (meaning they are thicker on one edge) to prevent the lenses from rotating.
Toric lenses are slightly more complicated to fit as the fit depends not only on the amount of astigmatism, but the shape of the eye too. For example lets say the axis of your cylinder power (astigmatism) is 90 degrees and so the Toric contact lens is ordered so that the weighted edge causes the lens to sit at 90 degrees... well sometimes the shape of the eye can cause the lens to rotate further in one direction... for example 10 degrees.
The lens then has to be ordered with an extra 10 degree compensation so that it sits in the correct place.
It is quite common for a lens to be prescribed using a combination of the sphere and cylindrical power, it is what we call a spherical equivalent and is generally used for milder amounts of astigmatism usually under 1 diopter.
For example if a person has 1 diopter of sphere and 1 diopter of astigmatism, the spherical equivalent is actually 1.5. If you added the full amount of both it would be far too strong and so typically only half of the astigmatism is added to the sphere to determine the contact lens power.
Coming back to the 3D aspect of all this, one has to remember that to see in 3D we must be able to see in a binocular manner, meaning both eyes together as this is how we are able to judge distance and use depth perception. So if one eye is not seeing as clearly, you will have a harder time with 3D glasses too. Of course seeing clearly in general is a factor too
Hacker
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I have a weird problem in my eyes my iris has overlapped a little bit with the sclera part. Far away things look a little blurred, went to see two doctors both of them said that its becoz of fatigue, they said that it should be fine in two months.
Anyone here has/had a similar problem?
Anyone here has/had a similar problem?
Well I went to this optical store last weekend. The dude told me that I cant get a contact lens since in one eye I have total cylindrical. Now as I read more and more about it, he seems completely out of touch of his profession.
My power is only -0.5 and -0.75, I just dont like wearing glasses and get eye strain without it. So as I see I can manage comfortably with spherical lens.
Also my axis keeps changing so I assuming its one of those corneal astigmatism conditions wherein the axis keeps changing due to eye dryness. I believe which is why the doctor had long back prescribed 'Genteal' to me.
My power is only -0.5 and -0.75, I just dont like wearing glasses and get eye strain without it. So as I see I can manage comfortably with spherical lens.
Also my axis keeps changing so I assuming its one of those corneal astigmatism conditions wherein the axis keeps changing due to eye dryness. I believe which is why the doctor had long back prescribed 'Genteal' to me.
@Renegade :
The fluctuating or changing power is called unstable. But there is no rule that only cylindrical powered person cant wear contact lenses.
You can get contact lenses for your vision also. Consult some good doctor first. then get your vision checked again after 6 months every 6 months for 2 years.
If your vision remains same with same correction power then you can go for better quality costly contact lenses.
Torric lense is a type where like in spectacle glasses there is correction of cylindrical power and as PixelPusher explained its made in such a way that it does not rotate in eye and stays put in the axis of astigmatism.
Secondly because of excessive looking at computer screen your vision will suffer from so called Computer Vision Syndrome so its highly likely that you may be getting early signs of it.
So protect your eyes, use LCD monitors, Keep brightness minimum possible, Take few seconds rest every 15 / 20 minutes : Closing your eyes and give circular massage for 10 / 15 seconds and that will do. Also fix your gaze to a distant object preferably outside naturally lit environment.
Never ever rely on optician`s judgement alone he is just a 12th grade pass technician, consult proper doctor and then go for the lenses.
Bausch & Laumb or Jonhson & Johnson are good brands for soft contact lenses be it torric or simple.
The fluctuating or changing power is called unstable. But there is no rule that only cylindrical powered person cant wear contact lenses.
You can get contact lenses for your vision also. Consult some good doctor first. then get your vision checked again after 6 months every 6 months for 2 years.
If your vision remains same with same correction power then you can go for better quality costly contact lenses.
Torric lense is a type where like in spectacle glasses there is correction of cylindrical power and as PixelPusher explained its made in such a way that it does not rotate in eye and stays put in the axis of astigmatism.
Secondly because of excessive looking at computer screen your vision will suffer from so called Computer Vision Syndrome so its highly likely that you may be getting early signs of it.
So protect your eyes, use LCD monitors, Keep brightness minimum possible, Take few seconds rest every 15 / 20 minutes : Closing your eyes and give circular massage for 10 / 15 seconds and that will do. Also fix your gaze to a distant object preferably outside naturally lit environment.
Never ever rely on optician`s judgement alone he is just a 12th grade pass technician, consult proper doctor and then go for the lenses.
Bausch & Laumb or Jonhson & Johnson are good brands for soft contact lenses be it torric or simple.
hyeah: