Peripheral vision

Horizontal section through the left eye, seen from above. The blind spot is around 15.5 °; the total area to the outside is about 107 °

Peripheral vision is the (conscious or unconscious) perception in the areas of the field of vision that are not mapped onto the central part of the retina , the fovea . While in the foveal vision of the detected object looked so the - will face line of the eye is aligned by eye movement precisely to the desired object to u. a. to utilize the maximum central visual acuity - the observer looks de facto past the object during peripheral (or indirect) vision. The peripheral vision has less visual acuity and provides optically slightly distorted visual impressions, but above all it has a far greater crowding effect . B. normal reading is not allowed.

The peripheral vision is very efficient for the perception of movements and because of its mainly for the light-dark sensitive rods of the retinal periphery useful even with extremely low brightness, when seeing in twilight and at night. The sensitivity for color perception is somewhat lower. B. flashing traffic signals conspicuous and / or with high-contrast colors such. B. Black / yellow shown. The temporal resolution is good, which was easy to determine in the past by looking at the bright picture of an older CRT TV out of the corner of your eye. The flickering was then much more clearly perceptible than when looking directly at the image. (Newer flat screens are not suitable for this demonstration.) Although peripheral vision covers more than 99.9% of the visual field , only around 50% of the optic nerve and around 50% of the area of the visual center (visual cortex) are available for its information. The remaining 50% are reserved for the high-resolution foveal system.

In the picture, the oval areas A, B and C show the parts of a chess situation that a chess master correctly recognizes from the periphery - i.e. without fixing them directly. The lines show the path of the eye fixations during 5 seconds, during which one had to try to memorize the position of the individual figures. The peripheral vision thus provides a first overall impression of a situation, which - if it is not immediately classified as dangerous - is usually subjected to a more precise analysis by the foveal system. As a reaction to the first impression, the eyes (the central line) are initially focused on a previously perceived peripheral point.

The total area of the field of vision (i.e. of peripheral vision) is about 107 ° to the outside (not 90 ° as incorrectly stated in many places). For both eyes together it is 214 ° (when looking straight ahead). Upwards it is about 60 ° –70 ° and downwards 70 ° –80 °; towards the nose, the area is limited to about 60 °, primarily by the presence of the nose. The blind spot is about 15.5 ° outwards in the field of view, just below the horizontal.

Areas of application

In daily vision, peripheral vision is used consciously or unconsciously, for example at every moment to determine the next fixation point or to supervise something on the side without looking up from work. With peripheral vision, the object being viewed can be obscured and the glare effect of a bright light source is more bearable if it is not fixed centrally.

People with a central scotoma , for example macular degeneration , often use peripheral areas of the retina to view things, even if only very blurred, that they could no longer see with central fixation. In ophthalmology this phenomenon is called eccentric attitude .

Peripheral vision is also referred to as indirect vision in astronomy and refers to a special observation technique with which very faint stars and flat objects ( nebula ) can be better recognized. You don't look directly at the celestial object, but just pass it.

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↑ ^a ^b ^c ^d Hans Strasburger: Seven myths on crowding and peripheral vision . In: i-Perception . 11, No. 2, 2020, pp. 1-45.
^ H. Strasburger, I. Rentschler, M. Jüttner: Peripheral vision and pattern recognition: a review . In: Journal of Vision . 11, No. 5, 2011, pp. 1-82.
↑ In Germany, with the image frequency of 50 Hz at that time; This was not possible in the USA, as 60 Hz frame rate was used there
↑ If you consider the area outside of around 2 ° eccentricity
↑ Image from: Hans-Werner Hunziker: In the eye of the reader: foveal and peripheral perception - from spelling to reading pleasure . Transmedia Stäubli Verlag, Zurich 2006, ISBN 978-3-7266-0068-6 ; based on data from: Adrianus Dingeman de Groot: Perception and memory in chess; an experimental study of the heuristics of the professional eye . Mimeograph, Psychological Laboratory University of Amsterdam, Seminar September 1969
^ K. Rohrschneider: Determination of the location of the fovea on the fundus . In: Investigative Ophthalmology & Visual Science . 45, No. 9, 2004, pp. 3257-3258.

[myths-1] Hans Strasburger: Seven myths on crowding and peripheral vision . In: i-Perception . 11, No. 2, 2020, pp. 1-45.

[Strasburger-2] H. Strasburger, I. Rentschler, M. Jüttner: Peripheral vision and pattern recognition: a review . In: Journal of Vision . 11, No. 5, 2011, pp. 1-82.

[3] In Germany, with the image frequency of 50 Hz at that time; This was not possible in the USA, as 60 Hz frame rate was used there

[4] If you consider the area outside of around 2 ° eccentricity

[5] Image from: Hans-Werner Hunziker: In the eye of the reader: foveal and peripheral perception - from spelling to reading pleasure . Transmedia Stäubli Verlag, Zurich 2006, ISBN 978-3-7266-0068-6 ; based on data from: Adrianus Dingeman de Groot: Perception and memory in chess; an experimental study of the heuristics of the professional eye . Mimeograph, Psychological Laboratory University of Amsterdam, Seminar September 1969

[6] K. Rohrschneider: Determination of the location of the fovea on the fundus . In: Investigative Ophthalmology & Visual Science . 45, No. 9, 2004, pp. 3257-3258.