Visual resolution and contour interaction in the fovea and periphery

doi:10.1016/0042-6989(79)90183-4

Vision Research

Volume 19, Issue 11, 1979, Pages 1187-1195

https://doi.org/10.1016/0042-6989(79)90183-4 Get rights and content

Abstract

The experiments provide quantitative data on the nature of contour interaction at the fovea and in the periphery to 10° eccentricity for observers with normal vision. Results with Landolt ring targets similar to those used by Flomet al. (J. opt. Soc. Am.53, 1026–1032) show that contour interaction effects are greater in peripheral vision. In central vision the increase in minimum angle of resolution (MAR) that occurred with the introduction of bars around the Landolt ring is small and much less than the experimental variation, whereas in peripheral vision bars at any of the ring-bar separations tested produced a consistent increase in MAR. Relationships between MAR and eccentricity are presented and compared with those in the literature. Reasons for the variation between previous studies are suggested.

Reference (26)

AnstisS.M.
A chart demonstrating variations in acuity with retinal position
Vision Res.
(1974)
BoumaH.
Visual interference in the parafoveal recognition of initial and final letters of words
Vision Res.
(1973)
LudvighE.
Extrafoveal visual acuity as measured with Snellen test letters
Am. J. Ophthal.
(1941)
MandelbaumJ. et al.
Peripheral visual acuity
Am. J. Ophthal.
(1947)
RaynerK. et al.
What guides a reader's eye movements?
Vision Res.
(1976)
SloanL.L.
The photopic acuity-luminance function with special reference to parafoveal vision
Vision Res.
(1968)
WeymouthF.W.
Visual sensory units and the minimum angle of resolution
Am. J. Ophthal.
(1958)
BaileyI.L. et al.
New design principles for visual acuity letter charts
Am. J. Optom. physiol. Opt.
(1976)
BaileyN.T.J.
Statistical Methods in Biology
(1959)
BerkeleyM.A. et al.
Grating visibility as a function of orientation and retinal eccentricity
Vision Res.
(1975)

BoumaH.

Interaction effects in parafoveal letter recognition

Nature

(1970)

BoumaH. et al.

Reading processes: On the recognition of single words in eccentric vision

I.P.O. Ann. Prog. Rept.

(1970)

EhlersH.

The movements of eyes during reading

Archs Ophthal.

(1936)

Cited by (158)

Effects of visual span on Chinese reading performance in normal peripheral vision
2022, Vision Research
The current study examined the relationships among temporal processing speed, spatial visual span and Chinese character reading speed in normal central and peripheral vision. Maximum reading speed (MRS) and critical print size (CPS) of 26 native Chinese readers (13 young and 13 older adults) were determined at three visual field locations: central vision, 10° left and 10° below fixation using a rapid serial visual presentation (RSVP) task. Temporal processing speed was measured using trigrams of randomly selected Chinese characters presented at a range of exposure durations, while spatial visual span was measured using trigrams presented at different spatial positions. It was found that shorter temporal processing speed and larger spatial visual span were associated with faster MRS at the central and inferior visual field locations, but not at the left of fixation location. As expected, reading and visual span metrics were better in central vision compared to both peripheral locations. In addition, reading, temporal processing, and spatial visual span metrics were better in the young than older subjects (except for similar temporal processing speed at two peripheral locations). The results for central and inferior presentation locations support the hypothesis that temporal processing speed and spatial visual span were associated with Chinese character reading speed. Surprisingly, no correlation was observed for the 10° left of the fixation location, suggesting that the factors affecting reading speed might differ for inferior and lateral peripheral viewing locations.
The role of eye movements in manual interception: A mini-review
2021, Vision Research
Citation Excerpt :
At the same time, head movements and small, fixational eye movements ensure sufficient retinal image motion during fixation to prevent fading caused by absolute stabilization (Martinez-Conde & Macknik, 2017; Rolfs, 2009). Because the fovea only covers ~1% of the visual field and visual resolution declines drastically in the periphery (Jacobs, 1979), humans and many other animals shift their eyes to align the fovea with an object by making quick, high-velocity eye movements called saccades (Land, 2019). Making a saccade to an object of interest not only provides foveal vision of the object, but also allows the observer to use two types of extraretinal signals about the eye position: (1) Proprioceptive feedback, which is derived from the stretch receptors in the ocular muscles (Steinbach, 1987; Bridgeman & Stark, 1991), and (2) efference copy (or corollary discharge) signals, which provide an internal copy of the oculomotor command (Bridgeman & Stark, 1991; Bridgeman, 1995; Sommer & Wurtz, 2008; Crapse & Sommer, 2008) and can be used as a feedforward signal in action and cognition (Subramanian, Alers, & Sommer, 2019).
When we catch a moving object in mid-flight, our eyes and hands are directed toward the object. Yet, the functional role of eye movements in guiding interceptive hand movements is not yet well understood. This review synthesizes emergent views on the importance of eye movements during manual interception with an emphasis on laboratory studies published since 2015. We discuss the role of eye movements in forming visual predictions about a moving object, and for enhancing the accuracy of interceptive hand movements through feedforward (extraretinal) and feedback (retinal) signals. We conclude by proposing a framework that defines the role of human eye movements for manual interception accuracy as a function of visual certainty and object motion predictability.
Upturn of the contour-interaction function at small flanking bar-to-target separations
2020, Vision Research
Citation Excerpt :
Thus, within the central ± 10 deg of the retina or so, any optical influence on the contour interaction function would be expected to be manifested within approximately the same small angular extent. However, because the angular subtense of a threshold acuity letter increases systematically from <5 min arc at the fovea to approximately 25 min arc at an eccentricity of 10 deg (Jacobs, 1979; Mandelbaum & Sloan, 1947; Musilová, Pluháček, Marten-Ellis, Bedell, & Siderov, 2018) both the width of the flanking bars and the range of target-to-flanker separations tested increase systematically with eccentricity from the fovea. Interestingly, Takahashi (1968) observed very similar threshold-elevating and threshold-lowering effects on foveal resolution thresholds using pairs of flanking bars with different widths (range 1.4 to ~55 min arc; her Figure 36).
Nearby flanking bars degrade letter identification and resolution, a phenomenon known as contour interaction. However, many previous studies found that the relationship between foveal letter identification and flanker separation is non-monotonic, with an upturn in performance at very small target-to-flanker separations. Here, we replicate this observation and show that a similar upturn occurs also for targets presented at 5 deg in the inferior field, if the target-to-flanker separation is sufficiently small. The presence and magnitude of the observed performance upturn depends on the flanking-bar width, being more evident for narrower compared to wider flanking bars. We interpret our results to indicate that neural interactions between nearby contours reduce performance when the target and flanking bars form discrete neural images. At sufficiently small separations, the images of the target and flanking bars can not be distinguished and performance is governed by the contrast of the target in the blended neural image.
Temporal Coding of Visual Space
2018, Trends in Cognitive Sciences
Citation Excerpt :
Only in a very small region at the center of gaze, the fovea, are cones packed sufficiently tightly to allow the high resolution we enjoy. Acuity drops rapidly as images fall outside this region [20,21], and even within the fovea cone density [22] and visual function [23] are not uniform, and attention exerts its influence [24]. To perceive the fine spatial structure of the world, we therefore need to center gaze on the area of interest by making saccadic eye movements (Box 1).
Establishing a representation of space is a major goal of sensory systems. Spatial information, however, is not always explicit in the incoming sensory signals. In most modalities it needs to be actively extracted from cues embedded in the temporal flow of receptor activation. Vision, on the other hand, starts with a sophisticated optical imaging system that explicitly preserves spatial information on the retina. This may lead to the assumption that vision is predominantly a spatial process: all that is needed is to transmit the retinal image to the cortex, like uploading a digital photograph, to establish a spatial map of the world. However, this deceptively simple analogy is inconsistent with theoretical models and experiments that study visual processing in the context of normal motor behavior. We argue here that, as with other senses, vision relies heavily on temporal strategies and temporal neural codes to extract and represent spatial information.
Crowding in the S-cone pathway
2016, Vision Research
The spatial extent of interference from nearby object or contours (the critical spacing of “crowding”) has been thoroughly characterized across the visual field, typically using high contrast achromatic stimuli. However, attempts to link this measure with known properties of physiological pathways have been inconclusive. The S-cone pathway, with its ease of psychophysical isolation and known anatomical characteristics, offers a unique tool to gain additional insights into crowding. In this study, we measured the spatial extent of crowding in the S-cone pathway at several retinal locations using a chromatic adaptation paradigm. S-cone crowding was evident and extensive, but its spatial extent changed less markedly as a function of retinal eccentricity than the extent found using traditional achromatic stimuli. However, the spatial extent agreed with that of low contrast achromatic stimuli matched for isolated resolvability. This suggests that common cortical mechanisms mediate the crowding effect in the S-cone and achromatic pathway, but contrast is an important factor. The low contrast of S-cone stimuli makes S-cone vision more acuity-limited than crowding-limited.
Crowding and visual acuity measured in adults using paediatric test letters, pictures and symbols
2016, Vision Research
Crowding refers to the degradation of visual acuity for target optotypes with, versus without, surrounding features. Crowding is important clinically, however the effect of target-flanker spacing on acuity for symbols and pictures, compared to letters, has not been investigated. Five adults with corrected-to-normal vision had visual acuity measured for modified single target versions of Kay Pictures, Lea Symbols, HOTV and Cambridge Crowding Cards, tests. Single optotypes were presented in isolation and with surrounding features placed 0–5 stroke-widths away. Visual acuity measured with Kay Picture optotypes is 0.13–0.19 logMAR better than for other test optotypes and varies significantly across picture. The magnitude of crowding is strongest when the surrounding features abut, or are placed 1 stroke-width away from the target optotype. The slope of the psychometric function is steeper in the region just beyond maximum crowding. Crowding is strongest and the psychometric function steepest, with the Cambridge Crowding Cards arrangement, than when any single optotype is surrounded by a box. Estimates of crowding extent are less variable across test when expressed in units of stroke-width, than optotype-width. Crowding for single target presentations of letters, symbols and pictures used in paediatric visual acuity tests can be maximised and made more sensitive to change in visual acuity, by careful selection of optotype, by surrounding the target with similar flankers, and by using a closer target-flanker separation than half an optotype-width.

View all citing articles on Scopus

¹: Present address: The Ohio State University, College of Optometry, 338 West Tenth Ave., Columbus, Ohio, 43210, U.S.A.

View full text

Visual resolution and contour interaction in the fovea and periphery

Abstract

Vision Res.

Vision Res.

Am. J. Ophthal.

Am. J. Ophthal.

Vision Res.

Vision Res.

Am. J. Ophthal.

New design principles for visual acuity letter charts

Am. J. Optom. physiol. Opt.

Statistical Methods in Biology

Grating visibility as a function of orientation and retinal eccentricity

Vision Res.

Interaction effects in parafoveal letter recognition

Nature

Reading processes: On the recognition of single words in eccentric vision

I.P.O. Ann. Prog. Rept.

The movements of eyes during reading

Archs Ophthal.