Difference between revisions of Distance vision

(5 intermediate revisions by 3 users not shown)

Line 1:

~~Your eye can focus on one distance at a time through [[accommodation]]~~. ~~Standard [[full prescriptions]] have a minimum~~ power of 0.~~25D, which would compensate for an~~ [[~~edge of blur~~]] ~~at 4 meters. 6 meters or 20 feet~~ is ~~considered as far as you possibly need~~ to ~~measure vision. Beyond that~~ the number of the [[rods and cones]] in the back of your eye ~~is a bigger limiting factor on vision than any tiny additional refraction bonus you could get~~.

'''Distance vision''' is, for practical purposes, anything over 6 meters or 20 feet. Because the difference in lens power from 6m to infinity is less than 0.2 [[Diopters]], the limiting factor is less about ability to focus than simply the resolution of the retina (the number of the [[rods and cones]] in the back of your eye).

As far as the [[ciliary muscle]] is concerned, your edge of blur is distance vision, no matter what the absolute distance, but you will have [[convergence]] at a near vision angle when looking at edge of blur through [[differentials]]. This is a possible mechanism of action for improvement, when the visual cortex notices the discrepancy between focus and convergence.

As far as the [[ciliary muscle]] is concerned, your [[Blur Horizon|edge of blur]] is distance vision, no matter what the absolute distance, but you will have [[convergence]] at a near vision angle when looking at edge of blur through [[differentials]]. This is a possible mechanism of action for improvement, when the [[visual cortex]] notices the discrepancy between focus and [[convergence]].

In the EndMyopia system, we use [[normalized]] glasses for outdoor work, for reading street signs, for looking out windows, and other distance vision tasks.

=See Also=

[[20-20-20 Rule]]

* [[3 hour rule]]

* [[20-20-20 Rule]]

* [[Close-up]]

[[Category:Articles]]

@@ Line 1: / Line 1: @@
-Your eye can focus on one distance at a time through [[accommodation]].  Standard [[full prescriptions]] have a minimum power of 0.25D, which would compensate for an [[edge of blur]] at 4 meters.  6 meters or 20 feet is considered as far as you possibly need to measure vision.  Beyond that the number of the [[rods and cones]] in the back of your eye is a bigger limiting factor on vision than any tiny additional refraction bonus you could get.
+'''Distance vision''' is, for practical purposes, anything over 6 meters or 20 feet. Because the difference in lens power from 6m to infinity is less than 0.2 [[Diopters]], the limiting factor is less about ability to focus than simply the resolution of the retina (the number of the [[rods and cones]] in the back of your eye).
-As far as the [[ciliary muscle]] is concerned, your edge of blur is distance vision, no matter what the absolute distance, but you will have [[convergence]] at a near vision angle when looking at edge of blur through [[differentials]].  This is a possible mechanism of action for improvement, when the visual cortex notices the discrepancy between focus and convergence.
+As far as the [[ciliary muscle]] is concerned, your [[Blur Horizon|edge of blur]] is distance vision, no matter what the absolute distance, but you will have [[convergence]] at a near vision angle when looking at edge of blur through [[differentials]].  This is a possible mechanism of action for improvement, when the [[visual cortex]] notices the discrepancy between focus and [[convergence]].
 In the EndMyopia system, we use [[normalized]] glasses for outdoor work, for reading street signs, for looking out windows, and other distance vision tasks.
 =See Also=
-[[20-20-20 Rule]]
+* [[3 hour rule]]
+* [[20-20-20 Rule]]
+* [[Close-up]]
+[[Category:Articles]]