Guide:Measuring with differentials - Revision history

Lloydmom at 13:39, 1 March 2024

2024-03-01T13:39:59Z

← Older revision		Revision as of 13:39, 1 March 2024
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	It is not uncommon to have trouble with measuring accurately, especially for individuals who have -4 or more diopters of myopia. The reason being that there is a much smaller margin for error in a range where one cm or less makes a difference of a quarter [[diopter]]. The best way to overcome ~~this~~ issue is to measure with [[differentials]].		It is not uncommon to have trouble with measuring accurately, especially for individuals who have -4 or more diopters of myopia, or a fair bit of cylinder requirement. The reason being that there is a much smaller margin for error in a range where one cm or less makes a difference of a quarter [[diopter]]. Also for those with higher cyl needs find that directional blur adds a lot of challenge . The best way to overcome either issue is to measure with [[differentials]].
	Chances are you know your differential correction without even having to look it up so substitute your correction and edge of blur into the example.		Chances are you know your differential correction without even having to look it up so substitute your correction and edge of blur into the example.

Lloydmom at 14:47, 10 May 2021

2021-05-10T14:47:17Z

← Older revision		Revision as of 14:47, 10 May 2021
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	So, your true myopia values are OD/OS -5.75/-4.75. Simple!		So, your true myopia values are OD/OS -5.75/-4.75. Simple!

			==See Also==
			[[Guide:How to measure your eyesight]]

Lloydmom: Created page with "It is not uncommon to have trouble with measuring accurately, especially for individuals who have -4 or more diopters of myopia. The reason being that there is a much smaller..."

2021-05-10T14:45:12Z

Created page with "It is not uncommon to have trouble with measuring accurately, especially for individuals who have -4 or more diopters of myopia. The reason being that there is a much smaller..."

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It is not uncommon to have trouble with measuring accurately, especially for individuals who have -4 or more diopters of myopia. The reason being that there is a much smaller margin for error in a range where one cm or less makes a difference of a quarter [[diopter]]. The best way to overcome this issue is to measure with [[differentials]].
Chances are you know your differential correction without even having to look it up so substitute your correction and edge of blur into the example.

==Example==
Suppose you are wearing a -4 differential in both eyes and you find your edge of blur to be 68cm.
Go to the [https://endmyopia.org/focal-calculator/calc.html calculator], and enter 68cm. The result is -1.5. The -4 you started with combines with the -1.5 you just determined you still require to indicate your true myopia to be -5.5.

Suppose you have [[Guide:OD/OS|OD/OS]] -4.25/-3.25, and find your edge of blur to be 68cm.

Go to the [https://endmyopia.org/focal-calculator/calc.html calculator], and enter in 68cm. The result is '''-1.50'''. Add this value to both of your eyes (be careful with negative numbers).

<math>OD\ (right\ eye): -4.25+(-1.50)=-5.75</math>

<math>OS\ (left\ eye): -3.25+(-1.50)=-4.75</math>

So, your true myopia values are OD/OS -5.75/-4.75. Simple!