Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
double vision, due to astigmatism?
#7
Bifocal, I think you meant to say: use +1.75 for reading and -1.75 for distance?

I've actually tried wearing plus lenses for near vision a year ago and it was just tiring on my eyes. I tend to read a lot and when I wore them I didn't feel like reading much. I may have gotten too strong a lens. I didn't know this when I bought my plus lens but there is a +3 diopter rule, where you add +3 to your distance prescription (for reading at a distance of 1/3 meter). I like reading comfortably without the plus lens for now though.

I haven't gotten a chance to carefully read the link you gave but found the term double vision. It's interesting what it says there:

"...how to explain the transient “double vision” of focused and unfocused versions of an object that arise in the process of adaptation? ...The retina is not single plane...But the photoceptors are distributed over multiple layers. Presumably, the most active receptors are those which are usually stimulated by well-focused images. After all, those are the ones whose signals the brain can interpret, and they receive the most reinforcement. For a myope, these will tend to be the receptors in the focal plane of close objects, toward the back of the retina. Because the myope is doing a lot of close work and spends less time looking in the distance, the closer retinal cells get less stimulation and suffer from underuse. However, if these closer layers can gradually get more stimulation, or example by using plus lenses, they will adapt to increase in sensitivity and the strength of their signalling to the visual cortex will gain prominence. At some point, weak signals from this forward layer (on which there is a sharper image) will be sent simultaneously with the stronger signals form the backward layer (on which the images are blurred). During the period of adaptation, activation of multiple layers will be perceived as a double-image."

I was under the impression that the double vision is due to astigmatism but the above explanation says it may be spherical and happening at the retina. Very interesting theory!
Reply

TEST YOUR VISION AT HOME!
- Free Eye Chart PDFs

  • 20 ft, 10 ft, and Near Vision Charts
  • Letters Calibrated to Correct Printed Size
Download Now

Messages In This Thread
double vision, due to astigmatism? - by lou_deg - 07-18-2012, 04:45 AM
RE: double vision, due to astigmatism? - by David - 09-25-2016, 09:00 AM
Re: double vision, due to astigmatism? - by lou_deg - 07-19-2012, 11:45 PM
Re: double vision, due to astigmatism? - by Nini - 02-22-2013, 08:22 AM
Re: double vision, due to astigmatism? - by Nini - 02-22-2013, 03:55 PM
Re: double vision, due to astigmatism? - by Nini - 02-23-2013, 01:44 AM
Re: double vision, due to astigmatism? - by Nini - 02-25-2013, 05:02 PM