<p>Assuming you are talking about the ability of the visual system to resolve <strong>spatial detail</strong> (resolution, if you wish), then your question is on <strong><a href="https://www.nlm.nih.gov/medlineplus/ency/article/003396.htm" rel="nofollow noreferrer">visual acuity</a> as a function of <a href="http://webvision.med.utah.edu/book/part-xiii-facts-and-figures-concerning-the-human-retina/" rel="nofollow noreferrer">eccentricity on the retina</a></strong> (Fig. 1). </p>

<p>Due to the densely packed cones at the fovea (corresponding to the central field of view (FOV), see Fig. 1), visual acuity (VA) is the greatest at the center of fixation. More eccentrically, VA declines markedly. <em>E.g.</em>, at 10 minutes of arc (1/6 of a degree) from fixation, there is a 25 % loss of visual acuity (Fig. 1.) This dependence of VA on eccentricity is indeed <strong>nonlinear</strong> (<em>cf</em>. Fig. 1) and correlates with the cone packing density and photopic resolution in the region up to a few degrees eccentricity. </p>

<p>However, at larger eccentricities, visual acuity is worse than that predicted by cone spacing alone, indicating that other post-receptoral retinal elements are the limiting factor. One of these factors is the <strong>increased density of rods in eccentric regions</strong>; rods are built for speed and <strong>sensitivity</strong>. The latter is accomplished in part by <strong>funneling the inputs of multiple rods onto a single retinal ganglion cell (RGC)</strong>. RGCs transmit the signals via the optic nerve to the visual centers in the brain stem, ultimately ending up in the brain. Foveal cones, on the other hand, are connected 1:1 and hence the spatial resolution and thus SA is much better in foveal regions. <strong>The foveal region contains high densities of cones</strong> (good VA), while more eccentrically more rods are present (worse VA); see Fig. 2. This is exactly the reason that we read by focusing our central foveal view on the characters. </p>

<p><a href="https://i.sstatic.net/vvdc4.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/vvdc4.jpg" alt="VA as function of eccentricity"></a><br>
<sup>Fig. 1. VA as a functin of eccentricity. Source: <a href="https://i.sstatic.net/vvdc4.jpg" rel="nofollow noreferrer">Kalloniatis &amp; Luu (2016)</a></sup></p>

<p><a href="https://i.sstatic.net/qoYbV.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/qoYbV.jpg" alt="Retina and photoRs"></a><br>
<sup>Fig. 2. Rod and cone densities as a function of eccentricity. Source: <a href="https://i.sstatic.net/vvdc4.jpg" rel="nofollow noreferrer">Kolb (2016)</a></sup></p>

<p><sub><strong>References</strong><br>
<strong>-</strong> <a href="https://i.sstatic.net/vvdc4.jpg" rel="nofollow noreferrer">Kalloniatis &amp; Luu. <strong>Visual acuity</strong>. In: <em>Webvision. The Organization of the Retina and Visual System</em>. Kolb <em>et al</em>. (eds). Utah University (2016)</a><br>
<strong>-</strong> <a href="http://webvision.med.utah.edu/book/part-ii-anatomy-and-physiology-of-the-retina/photoreceptors/" rel="nofollow noreferrer">Kolb. <strong>Photoreceptors</strong>. In: <em>Webvision. The Organization of the Retina and Visual System</em>. Kolb <em>et al</em>. (eds). Utah University (2016)</a></sub></p>

CC BY-SA 3.0
2016-05-25T21:36:33.730Z
2016-05-27T05:49:46.037Z
2016-05-27T05:49:46.037Z
AliceD
<p>I have read somewhere that </p>

<blockquote>
  <p>Our visual perception degrades non-linearly with distance from the
  fovea.</p>
</blockquote>

<p>However, it was not referenced. I was wondering if there is a reference talking about this? </p>

<p>Also, is there a scientific reference stating the degradation of vision as a function of degrees in the field of view?</p>

<neuroscience><vision><neurophysiology>
What is the relation of visual quality and distance from the central field of view?
Tina J
# What is the relation of visual quality and distance from the central field of view?

(Asked by: username_0 on 2016-05-25)

I have read somewhere that

> Our visual perception degrades non-linearly with distance from the
> fovea.

However, it was not referenced. I was wondering if there is a reference talking about this?

Also, is there a scientific reference stating the degradation of vision as a function of degrees in the field of view?

**Tags:** neuroscience, vision, neurophysiology


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## 1 answers

### Answer by username_1 on 2016-05-25. Score: 2

Assuming you are talking about the ability of the visual system to resolve **spatial detail** (resolution, if you wish), then your question is on **[visual acuity](https://www.nlm.nih.gov/medlineplus/ency/article/003396.htm) as a function of [eccentricity on the retina](http://webvision.med.utah.edu/book/part-xiii-facts-and-figures-concerning-the-human-retina/)** (Fig. 1).

Due to the densely packed cones at the fovea (corresponding to the central field of view (FOV), see Fig. 1), visual acuity (VA) is the greatest at the center of fixation. More eccentrically, VA declines markedly. *E.g.*, at 10 minutes of arc (1/6 of a degree) from fixation, there is a 25 % loss of visual acuity (Fig. 1.) This dependence of VA on eccentricity is indeed **nonlinear** (*cf*. Fig. 1) and correlates with the cone packing density and photopic resolution in the region up to a few degrees eccentricity.

However, at larger eccentricities, visual acuity is worse than that predicted by cone spacing alone, indicating that other post-receptoral retinal elements are the limiting factor. One of these factors is the **increased density of rods in eccentric regions**; rods are built for speed and **sensitivity**. The latter is accomplished in part by **funneling the inputs of multiple rods onto a single retinal ganglion cell (RGC)**. RGCs transmit the signals via the optic nerve to the visual centers in the brain stem, ultimately ending up in the brain. Foveal cones, on the other hand, are connected 1:1 and hence the spatial resolution and thus SA is much better in foveal regions. **The foveal region contains high densities of cones** (good VA), while more eccentrically more rods are present (worse VA); see Fig. 2. This is exactly the reason that we read by focusing our central foveal view on the characters.

[![VA as function of eccentricity](https://i.sstatic.net/vvdc4.jpg)](https://i.sstatic.net/vvdc4.jpg)  
Fig. 1. VA as a functin of eccentricity. Source: [Kalloniatis & Luu (2016)](https://i.sstatic.net/vvdc4.jpg)

[![Retina and photoRs](https://i.sstatic.net/qoYbV.jpg)](https://i.sstatic.net/qoYbV.jpg)  
Fig. 2. Rod and cone densities as a function of eccentricity. Source: [Kolb (2016)](https://i.sstatic.net/vvdc4.jpg)

**References**  
**-** [Kalloniatis & Luu. **Visual acuity**. In: *Webvision. The Organization of the Retina and Visual System*. Kolb *et al*. (eds). Utah University (2016)](https://i.sstatic.net/vvdc4.jpg)  
**-** [Kolb. **Photoreceptors**. In: *Webvision. The Organization of the Retina and Visual System*. Kolb *et al*. (eds). Utah University (2016)](http://webvision.med.utah.edu/book/part-ii-anatomy-and-physiology-of-the-retina/photoreceptors/)


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