Author Topic: Online test for astigmatism  (Read 21272 times)

Offline johnlink

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Re: Online test for astigmatism
« Reply #45 on: March 20, 2013, 06:35:53 AM »

Yes the vertical lines are close to equally black at about 22cm away, so that would mean that axis is -4.5 diopters. I have tried pushing print that way but it seems that would induce strain in the stronger axis.


I think I didn't make my question clear, so I'll ask again. Is there a distance at which the vertical and horizontal lines of the image in http://forum.gettingstronger.org/index.php/topic,468.msg3987.html#msg3987 appear with the same darkness? For me that distance is about 6 inches.
« Last Edit: March 20, 2013, 06:40:12 AM by johnlink »

Offline PhilippK

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Re: Online test for astigmatism
« Reply #46 on: March 20, 2013, 06:53:41 AM »

Yes the vertical lines are close to equally black at about 22cm away, so that would mean that axis is -4.5 diopters. I have tried pushing print that way but it seems that would induce strain in the stronger axis.


I think I didn't make my question clear, so I'll ask again. Is there a distance at which the vertical and horizontal lines of the image in http://forum.gettingstronger.org/index.php/topic,468.msg3987.html#msg3987 appear with the same darkness? For me that distance is about 6 inches.

Your question was perfectly clear and I answered it 22cm or close to 9 inches is the distance that both lines are equally black. When I zoom out the vertical lines start getting thinner and grey.

Offline johnlink

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Re: Online test for astigmatism
« Reply #47 on: March 20, 2013, 07:03:50 AM »

Your question was perfectly clear and I answered it 22cm or close to 9 inches is the distance that both lines are equally black. When I zoom out the vertical lines start getting thinner and grey.


When you zoom out do the horizontal lines get thicker and darker? When you zoom in from 22 cm do the horizontal lines get thinner and grey and the vertical lines thicker and darker?

Offline PhilippK

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Re: Online test for astigmatism
« Reply #48 on: March 20, 2013, 07:24:31 AM »

Your question was perfectly clear and I answered it 22cm or close to 9 inches is the distance that both lines are equally black. When I zoom out the vertical lines start getting thinner and grey.


When you zoom out do the horizontal lines get thicker and darker? When you zoom in from 22 cm do the horizontal lines get thinner and grey and the vertical lines thicker and darker?

At about 12cm the horizontal lines start to lose focus and get thinner and grey while the vertical is in complete focus. Zooming out from 22cm doesn't make the horizontal lines any thicker or darker.

Offline johnlink

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Re: Online test for astigmatism
« Reply #49 on: April 15, 2013, 05:17:00 AM »

Hi John,

You ask me, "... exactly how I stand" on astigmatism.


I never asked you any such thing.