Visual Acuity Within the Area Centralis and Its Relation to Eye Movements and Fixation

Weymouth, Frank W.; Hines, Don Carlos; Acres, Lawrence H.; Raaf, John; Wheeler, Maynard C.

doi:10.1097/00006324-196309000-00004

Cited by 8 publications

(10 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These studies of reading and scanning are consistent with the finding that target detection, discrimination, and location, in both cued and uncued conditions in an eyes-fixed paradigm, are superior along the horizontal as opposed to the vertical axis (Carrasco, Talgar & Cameron, 2001). As these authors hypothesize, these findings appear to reflect the fact that acuity drops off faster with vertical distance from the fovea than with horizontal distance (Weymouth, Hines, Acres, Raaf & Wheeler, 1928) which in turn reflects anatomical studies of cone spacing in the fovea and perifovea (Curcio & Allen, 1990). In corroborating and extending these prior studies, our results suggest that in response to smaller perceptual span and greater fall-off in acuity along the vertical axis subjects adopt a scanning strategy in which the items scanned per fixation and saccade amplitude are smaller while fixation duration increases much less.…”

Section: Discussionmentioning

confidence: 87%

The dependence of visual scanning performance on search direction and difficulty

Phillips

2008

Vision Research

View full text Add to dashboard Cite

Phillips & Edelman (2008) presented evidence that performance variability in a visual scanning task depended on oculomotor variables related to saccade amplitude rather than fixation duration, and that saccade-related metrics reflected perceptual span. Here, we extend these results by showing that even for extremely difficult searches trial-to-trial performance variability still depends on saccade-related metrics and not fixation duration. We also show that scanning speed is faster for horizontal than for vertical searches, and that these differences derive again from differences in saccade-based metrics and not from differences in fixation duration. We find perceptual span to be larger for horizontal than vertical searches, and approximately symmetric about the line of gaze.

show abstract

Section: Discussionmentioning

confidence: 87%

The dependence of visual scanning performance on search direction and difficulty

Phillips

2008

Vision Research

View full text Add to dashboard Cite

show abstract

“…In fact, direct psychophysical evaluation with stimuli at very small eccentricity angles has given mixed results. Some studies have found a decline in performance with eccentricity, whereas others have reported minimal changes (Weymouth et al, 1928; Millodot, 1972). Mapping foveal vision is, however, a very challenging task.…”

Section: Visual Functions Of Microsaccadesmentioning

confidence: 99%

A compact field guide to the study of microsaccades: Challenges and functions

2016

View full text Add to dashboard Cite

Following a period of quiescence at the end of last century, the study of microsaccades has now regained strong impetus and broad attention within the vision research community. This new wave of interest, partly fueled by the advent of a new generation of high-resolution eyetrackers, has attracted new researchers and led to new ideas. Old hypothesis have been revisited and new ones formulated. This article is designed to serve as a practical guide for researchers in the field. Because of the history of the field and the difficulty of measuring very small eye movements, the study of microsaccades presents peculiar challenges. Here, we summarize some of the main challenges and describe methods for assessing and improving the quality of the recordings. Furthermore, we examine how these experimental challenges have influenced analysis of the visual functions of microsaccades and critically review current evidence on three long-debated proposals: the maintenance of fixation, the prevention of visual fading, and the exploration of fine spatial detail.

show abstract

“…Humans collect visual information from a remarkably broad field of view, covering an angle larger than 180° . Monitoring such a wide area, however, comes at a cost: a variety of visual functions including acuity are not uniform throughout the visual field, but progressively deteriorate with increasing distance from a small region, approximately the size of the full moon in the sky (Weymouth et al 1928; Jacobs 1979; Legge & Kersten 1987; Hansen, Pracejus & Gegenfurtner 2009; Nandy & Tjan 2012). This is the portion of the visual field that projects onto the foveola, the tiny region of the retina where rods receptors are absent and cones most densely packed.…”

Section: Vision and Eye Movementsmentioning

confidence: 99%

“…Some studies have reported a decline in performance with eccentricity, whereas others have found minimal changes (Weymouth et al 1928; Adler & Meyer 1935; Millodot 1966). However, it is critical to realize that testing visual acuity at very small eccentricities is extremely challenging.…”

Section: Visual Functions Of Microsaccadesmentioning

confidence: 99%

Control and Functions of Fixational Eye Movements

Rucci

Poletti

2015

Annu. Rev. Vis. Sci.

183

151

View full text Add to dashboard Cite

Humans and other species explore a visual scene by rapidly shifting their gaze 2-3 times every second. Although the eyes may appear immobile in the brief intervals in between saccades, microscopic (fixational) eye movements are always present, even when attending to a single point. These movements occur during the very periods in which visual information is acquired and processed and their functions have long been debated. Recent technical advances in controlling retinal stimulation during normal oculomotor activity have shed new light on the visual contributions of fixational eye movements and their degree of control. The emerging body of evidence, reviewed in this article, indicates that fixational eye movements are important components of the strategy by which the visual system processes fine spatial details, enabling both precise positioning of the stimulus on the retina and encoding of spatial information into the joint space-time domain.

show abstract

Visual Acuity Within the Area Centralis and Its Relation to Eye Movements and Fixation

Cited by 8 publications

References 0 publications

The dependence of visual scanning performance on search direction and difficulty

The dependence of visual scanning performance on search direction and difficulty

A compact field guide to the study of microsaccades: Challenges and functions

Control and Functions of Fixational Eye Movements

Contact Info

Product

Resources

About