Question about cylinder #s for astigmatism?!
Question: Question about cylinder #s for astigmatism!?
I have astigmatism in both eyes at -!.50!. Is this measured on the same scale as a sphere Rx meaning -!.50 cylinder is just as mild as a -!.50 sphere measurement!? Do the plus and minus signs before a cylinder number indicate farsightedness (for +) and nearsightedness (for -)!?Www@Answer-Health@Com
Answers:
The cylinder is different in the sense that it corrects only in one meridian!. That's what the axis number determines!.
The Sphere power is the same througout the lens, but the cylinder is more specific in correcting only in one direction!.
The difference between a + or - cylinder is all in how the prescription was written!.
Ophthalmologists write thier Rx's in the + cyl form, while optometrists and the rest of the industry use the - cyl form!.
So, an Rx from an Opthalmologist always has to be converted to the - form to be fabricated!.!. It is just 2 different ways of getting to the same result!.
For instance a lens that is - 1!.00 - 0!.50 X 90!.!.!.is the same as - 1!.50 + 0!.50 X 180
A simple example would be like the letter " T "!.!.!.astigmatism could make the cross bar blurry, while the vertical bar is clear, ( depending on the axis)!.!.!.so the cylinder correction would just bend the light to bring that cross bar into focus, the same as the vertical bar!.
Hope this clears up your question!.
Www@Answer-Health@Com
The Sphere power is the same througout the lens, but the cylinder is more specific in correcting only in one direction!.
The difference between a + or - cylinder is all in how the prescription was written!.
Ophthalmologists write thier Rx's in the + cyl form, while optometrists and the rest of the industry use the - cyl form!.
So, an Rx from an Opthalmologist always has to be converted to the - form to be fabricated!.!. It is just 2 different ways of getting to the same result!.
For instance a lens that is - 1!.00 - 0!.50 X 90!.!.!.is the same as - 1!.50 + 0!.50 X 180
A simple example would be like the letter " T "!.!.!.astigmatism could make the cross bar blurry, while the vertical bar is clear, ( depending on the axis)!.!.!.so the cylinder correction would just bend the light to bring that cross bar into focus, the same as the vertical bar!.
Hope this clears up your question!.
Www@Answer-Health@Com
"Is this measured on the same scale as a sphere Rx meaning -!.50 cylinder is just as mild as a -!.50 sphere measurement!?"
well both astigmatism and sphere power are measured in "diopters", but generally astigmatism does not cause as much blur as the same amount of corresponding sphere power!. so -0!.50 cyl is less blurry (about 1/2 as blurry, actually) than -0!.50 sphere
"Do the plus and minus signs before a cylinder number indicate farsightedness (for +) and nearsightedness (for -)!?"
no!. plus and minus signs before the sphere power indicate farsightedness and nearsightedness respectively, but plus and minus signs before the cyl power just indicate whether the refractionist chose to use a convex cylinder or a concave cylinder to measure the astigmatism!. plus cyl is not "farsighted astigmatism" and minus cyl is not "nearsighted astigmatism!. astigmatism is astigmatism!.!.!.the plus and minus are just different ways of measuring and/or describing the astigmatism!.Www@Answer-Health@Com
well both astigmatism and sphere power are measured in "diopters", but generally astigmatism does not cause as much blur as the same amount of corresponding sphere power!. so -0!.50 cyl is less blurry (about 1/2 as blurry, actually) than -0!.50 sphere
"Do the plus and minus signs before a cylinder number indicate farsightedness (for +) and nearsightedness (for -)!?"
no!. plus and minus signs before the sphere power indicate farsightedness and nearsightedness respectively, but plus and minus signs before the cyl power just indicate whether the refractionist chose to use a convex cylinder or a concave cylinder to measure the astigmatism!. plus cyl is not "farsighted astigmatism" and minus cyl is not "nearsighted astigmatism!. astigmatism is astigmatism!.!.!.the plus and minus are just different ways of measuring and/or describing the astigmatism!.Www@Answer-Health@Com