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:10.1016/s0002-9394(28)90119-1

Cited by 123 publications

(26 citation statements)

References 8 publications

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“…These results, obtained on naïve individuals, are similar to that determined in prior investigations of laboratory investigators using sinusoidal gratings, 34,35 Landolt C rings, [37][38][39][40] and Snellen letters [41][42][43] with similar presentation times. Similar to most authors, we also showed a linear deterioration of acuity with eccentricity.…”

Section: Discussionsupporting

confidence: 86%

Central field perimetry of discriminated targets: I. Results for normal individuals using high-contrast targets

Yavuz

Ünver

Bekiroğlu

et al. 2009

Eye

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Purpose A new perimetry method is described to evaluate central vision under multiple hue, illumination, and contrast conditions; results are described for normal individuals using high-contrast targets. Methods For 70 normal eyes of individuals with varying age, the ETDRS chart acuity was determined as well as discriminated target perimetry using high-contrast targets presented for 250 ms at locations up to 101 eccentricity. Retesting was performed to evaluate for learning and repeatability for the thresholded acuity at each eccentricity. Results The ETDRS acuity averaged 1.15 ± 0.37 arc min minimum angle of resolution (MAR) with best correction (20/23 equivalence). At fixation, the thresholded acuity for high-contrast targets paralleled the ETDRS acuity and averaged 1.75±0.85 arc min MAR (20/35 equivalence), and declined with increasing eccentricity in a linear fashion to 5.81 ± 3.97 arc min (20/116 equivalent) at 101 eccentricity. Linear regression showed Vmar ¼ 1.74 þ 0.330 * eccentricity in degrees (R 2 ¼ 0.966, Po0.0001). Testing time required B8-10 min per eye. Repeated testing showed only minimal learning experience at the most peripheral locations. The test-retest 95% confidence limits of difference measured 1.12 arc mins MAR at fixation (64% of the mean) and remained approximately the same proportion to the mean thresholded acuity outwards to 101 eccentricity. Conclusion The methodology seems rapid and reliable for measuring discriminatory visual function of optotype targets throughout the central 201 diameter visual field.

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Section: Discussionsupporting

confidence: 86%

Central field perimetry of discriminated targets: I. Results for normal individuals using high-contrast targets

Yavuz

Ünver

Bekiroğlu

et al. 2009

Eye

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“…In both conditions, word recognition was best when the word center was fixated. Performance was generally better for horizontal words than for vertical words, which is in line with the results in Weymouth et al (1928). Collectively, the results from single-word reading studies suggest that visual acuity is a major determinant of the OVP phenomenon.…”

Section: Viewing Position Effects In Readingsupporting

confidence: 84%

“…Visual acuity rapidly drops with increasing distance from the center of the fovea. It decreases systematically for both the vertical and the horizontal meridians, but the drop of acuity with eccentricity is stronger in the vertical than in the horizontal meridian (Weymouth et al, 1928). Thus, the letters of a word are most rapidly identified when the eyes are on the line of text.…”

Section: Discussionmentioning

confidence: 92%

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Not fixating at the line of text comes at a cost

Nuthmann

2013

Atten Percept Psychophys

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Previous research on eye guidance in reading has investigated systematic tendencies with respect to horizontal fixation locations on letters within words and the relationship between fixation location in a word and the duration of the fixation. The present study investigates where readers place their eyes vertically on the line of text and how vertical fixation location is related to fixation duration. Analyses were based on a large corpus of eye movement recordings from single-sentence reading. The vertical preferred viewing location was found to be within the vertical extent of the font, but fixations beyond the vertical boundaries of the text also frequently occurred. Analyzing fixation duration as a function of vertical fixation location revealed a vertical optimal viewing position (vOVP) effect: Fixations were shortest when placed optimally on the line of text, and fixation duration gradually increased for fixations that fell above or below the line of text. The vOVP effect can be explained by the limits of visual resolution along the vertical meridian. It is concluded that vertical and horizontal landing positions in singlesentence reading are associated with differences in fixation durations in opposite ways.

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“…Vos (1963) (Wentworth, 1930), acuity (Katzenellenbogen, 1907;Mandelbaum & Sloan, 1947). However, Weymouth, Hines, Acres, Raaf, and Wheeler (1928) investigated acuity in this retinal region and did not find such an inflexion.…”

mentioning

confidence: 96%

The retinal threshold gradient in the presence of a high-luminance target and in total darkness

Haines

1971

Perception & Psychophysics

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The retinal threshold gradient in the presence of a high-luminance target and in total darkness"The retinal threshold was measured along the horizontal meridian for the dark-adapted eye and for the same retinal region light-adapted by stray light from a small foveally fixated high-luminance target. This was done to quantify the irradiation phenomenon in the foveal-parafoveal boundary region. Two target luminances were investigated (5,531 and 13,000 fL). Seven Ss made threshold settings using a variable-intensity test spot

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Visual Acuity within the Area Centralis and its Relation to Eye Movements and Fixation

Cited by 123 publications

References 8 publications

Central field perimetry of discriminated targets: I. Results for normal individuals using high-contrast targets

Central field perimetry of discriminated targets: I. Results for normal individuals using high-contrast targets

Not fixating at the line of text comes at a cost

The retinal threshold gradient in the presence of a high-luminance target and in total darkness

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