I read on another site that: 1/2 the cylinder measurement + the sphere measurement = diopter strength. Because I have a lot of astigmatism this changes the measurements quite a bit (-3.25 cylinder, -3 sphere). Has anybody else used this equation to determine the strength in buying goggles? I read on another site that: 1/2 the cylinder measurement + the sphere measurement = diopter strength. Because I have a lot of astigmatism this changes the measurements quite a bit (-3.25... » Read More I read on another site that: 1/2 the cylinder measurement + the sphere measurement = diopter strength. Because I have a lot of astigmatism this changes the measurements quite a bit (-3.25 cylinder, -3 sphere). Has anybody else used this equation to determine the strength in buying goggles? « Show Less
107802
That equation is correct... it is called spherical equivalent. With a -3.00 sphere and -3.25 cylinder, your spherical equivalent is -4.50. Keep in mind this will give you pretty decent vision - good enough to see at a reasonable distance, but this will not be equal to a full spectacle prescription. I am an optometrist.
40139
That's the method we used when buying my daughter's goggles. She ended up with -3.625 (R) and -4.25 (L) so we split the difference with a -4 prescription. She says they work well enough for her, and she has to be read a white board to get her workout during swim practice.
107803
hi, none of us are opticians. I'd give them a call and ask. That way you'll get a pair of goggles that you can use to read underwater - haha - but seriously, I was thrilled when I could see clearly underwater. It's worth the effort!
2263148
with out the 3x magnifier I wanted the two dot easy to see . with out the 3x magnifier over two dots hard to see them . yeah with 4 dots and no &#9726;3x magnifier looks like a straight line. I dint want the weight and pay the extra cash. my friend has the 4 dot and 3x magnifier really nice set up. hope this helped you :)
187865
I bought these for my husband who normally uses a 2.00 strength. I've borrowed them and can see great (I usually use a 2.50). I don't know what 200 means per the description of the maker--maybe a typo?
897742
I have been satisfied with my refractometer so far. I previously had one that came in a gem lab I purchased 25 years ago and it wasnt nearly as easy to read as this one. No complaints to this point.
1781401
I don't know, but I've moved on to Splaqua corrective swim goggled--better deal, lot of different diopter corrections, they come with the lens in and they are cheaper.
1750
My answer is the same as the others who explained that the numbers refer to the strength of the lenses. You can go into any drugstore or Walmart or dollar store and use their glasses display to figure out what strength you need. The advantage of the Clic glasses is that you can keep them around your neck when you don't need them to read something.
377710
I not sure what you mean by 'strength'. I certainly do not have a spectrum analyzer or light meter to measure intensity and wave lengths from a specification perspective. What I can tell you is that I have prior experience with UV light in water supply systems and air vent systems and the results I have achieved with this device are consistent with these other better known systems/applications. Furthermore, like I posted, this is not a toy and should be handled as a tool. I also bought the UV glasses for eye protection, keep my skin out of the light ray, and keep me kids away when in use. One really good indication of it working is the 'ozone' smell associated with disinfected area. It is the same smell you get after a lightning strike. To find out how it works, I would suggest looking into water supply UV light systems. It takes very little exposure to UV light to kill bacteria that can be found in well water. I would be happy to share specific details if know the application for which you are considering this purchase.
814584
Hey you properly calibrated it by using RODI water. You must put RODI water where you use it for the saltwater then just above it is a black cap an under the cap is a screw to calibrate it. So look into the eye part then adjust it to zero then it should work fine
614136
Some people with an astigmatism will see more than one dot or the dot will seem out of round. I am one of those people and you just get use to it over time. My aimpont and delta point do the same thing.
1190631
As per previous answer it is just standard adapter for a camera specific T ring so you can attach camera to telescope that has 1.25 eyepiece It will not give more "strength" (I assume you mean magnification).
118248
I ordered about 3 month ago this model refractometer. I bought also one wine triple scale hydrometer (Specific gravity,BXº and % potencial alcohol).Comparing them,(hydrometer and refractometer) ,i found the relative wrong in BXº readings are so small as 1.5%,and Specific gravity are smaller than this. Comparing refractometer results readings with theorical values of one BXº vs. S.G setting chart,I found relative wrongs reachs up to 6.8%.
2089240
My belief is that the True Depth $53.00 glasses actually do give better depth results. This in not scientific but my opinion. I would stick to the True Depth model.
581157
As effective? That depends on what you mean... As effective against eye strain.. No. Period.This is readily confirmed at Gunnar's website:http://www.gunnars.com/view_crystal_lenses.php"The CRySTALLINE lens tint and coating formula is designed specifically for the graphic designer, video/film editor, or creative visual artist that requires an equally balanced color spectrum. If your profession does not allow for a shift towards the warmer part of the color spectrum, with enhanced contrast ie. your tasks require you to design or work in true color, then this lens option is for you. However, if your profession does not require you to perform many daily tasks in true color, then AMBeR is the most effective lens choice." As effective? That depends on what you mean... As effective against eye strain.. No. Period.This is readily confirmed at Gunnar's website:http://www.gunnars.com/view_crystal_lenses.php"The CRySTALLINE lens tint and coating formula is designed specifically for the graphic designer, video/film editor, or creative visual artist that requires an equally balanced color spectrum. If your profession does not allow for a shift towards the warmer part of the color spectrum, with enhanced contrast ie. your tasks require you to design or work in true... » Read More As effective? That depends on what you mean... As effective against eye strain.. No. Period.This is readily confirmed at Gunnar's website:http://www.gunnars.com/view_crystal_lenses.php"The CRySTALLINE lens tint and coating formula is designed specifically for the graphic designer, video/film editor, or creative visual artist that requires an equally balanced color spectrum. If your profession does not allow for a shift towards the warmer part of the color spectrum, with enhanced contrast ie. your tasks require you to design or work in true color, then this lens option is for you. However, if your profession does not require you to perform many daily tasks in true color, then AMBeR is the most effective lens choice." « Show Less
1746
That is the strength of the reading glass. The higher the number the greater the magnification. It is not at all about the size as it will fit your head.
1683132
It depends on what you'd eyeglass prescription is. You should check with you Optomotridt and find out what your prescription is and then get the diopter closest to that.Rich Signorelli
967887
The magnifying strength is 3x, with a 5x, 1" bubble. I have never figured out how to use it to magnify my cross stitch cloth, only the pattern, which is still a great help.
64369
Because of the difference I would suggest buying 1 pair in each of the diopters you need and swapping out the lenses. For me the difference was only 1 point so I went up a half. They've worked out great.