Eccentric Gaze Direction in Patients with Central Field Loss

Verezen, C.A.; Hoyng, Carel B.; Meulendijks, C.F.M.; Keunen, J. E. E.; Klevering, B. Jeroen

doi:10.1097/opx.0b013e31822891e0

Cited by 9 publications

(8 citation statements)

References 49 publications

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“…This is consistent with past findings that many patients place their scotoma up and to the right when they eccentrically view. 28–31 This preference is interesting in that it doesn’t appear to depend on which eye is used, as is the case also for the small sample of patients reported here.…”

Section: Resultssupporting

confidence: 51%

Scotoma Visibility and Reading Rate with Bilateral Central Scotomas

Pratt¹,

Stevenson²,

Bedell

2017

Optom Vis Sci

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Purpose In this experiment we tested whether perceptually delineating the scotoma location and border with a gaze contingent polygon overlay improves reading speed and reading eye movements in patients with bilateral central scotomas. Methods Eight patients with age related macular degeneration and bilateral central scotomas read aloud MNRead style sentences with their preferred eye. Eye movement signals from an EyeLink II eyetracker were used to create a gaze contingent display in which a polygon overlay delineating the area of the patient’s scotoma was superimposed on the text during 18 of the 42 trials. Blocks of 6 trials with the superimposed polygon were alternated with blocks of 6 trials without the polygon. Reading speed and reading eye movements were assessed before and after the subjects practiced reading with the polygon overlay. Results All of the subjects but one showed an increase in reading speed. A paired-samples t test for the group as a whole revealed a statistically significant increase in reading speed of 0.075 ± 0.060 (SD) log wpm after reading with the superimposed polygon. Individual subjects demonstrated significant changes in reading eye movements, with the greatest number of subjects demonstrating a shift in the average vertical fixation locus. Across subjects, there was no significant difference between the initial and final reading eye movements in terms of saccades/s, average fixation duration, average amplitude of saccades, or proportion of non-horizontal saccades. Conclusions The improvement in reading speed (0.075 log wpm or 19%) over the short experimental session for the majority of subjects indicates that making the scotoma location more visible is potentially beneficial for improving reading speed in patients with bilateral central scotomas. Additional research to examine the efficacy of more extended training with this paradigm is warranted.

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Section: Resultssupporting

confidence: 51%

Scotoma Visibility and Reading Rate with Bilateral Central Scotomas

Pratt¹,

Stevenson²,

Bedell

2017

Optom Vis Sci

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“…People with CFL almost always use a preferred retinal locus (PRL), an extra-foveal location near the scotoma, to fixate targets that would normally be foveally fixated [4], [5]. Thus they not only have a blind area in central vision, but also impaired visual acuity and contrast sensitivity [6].…”

Section: Introductionmentioning

confidence: 99%

Visual Attention Measures Predict Pedestrian Detection in Central Field Loss: A Pilot Study

et al. 2014

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PurposeThe ability of visually impaired people to deploy attention effectively to maximize use of their residual vision in dynamic situations is fundamental to safe mobility. We conducted a pilot study to evaluate whether tests of dynamic attention (multiple object tracking; MOT) and static attention (Useful Field of View; UFOV) were predictive of the ability of people with central field loss (CFL) to detect pedestrian hazards in simulated driving.Methods11 people with bilateral CFL (visual acuity 20/30-20/200) and 11 age-similar normally-sighted drivers participated. Dynamic and static attention were evaluated with brief, computer-based MOT and UFOV tasks, respectively. Dependent variables were the log speed threshold for 60% correct identification of targets (MOT) and the increase in the presentation duration for 75% correct identification of a central target when a concurrent peripheral task was added (UFOV divided and selective attention subtests). Participants drove in a simulator and pressed the horn whenever they detected pedestrians that walked or ran toward the road. The dependent variable was the proportion of timely reactions (could have stopped in time to avoid a collision).ResultsUFOV and MOT performance of CFL participants was poorer than that of controls, and the proportion of timely reactions was also lower (worse) (84% and 97%, respectively; p = 0.001). For CFL participants, higher proportions of timely reactions correlated significantly with higher (better) MOT speed thresholds (r = 0.73, p = 0.01), with better performance on the UFOV divided and selective attention subtests (r = −0.66 and −0.62, respectively, p<0.04), with better contrast sensitivity scores (r = 0.54, p = 0.08) and smaller scotomas (r = −0.60, p = 0.05).ConclusionsOur results suggest that brief laboratory-based tests of visual attention may provide useful measures of functional visual ability of individuals with CFL relevant to more complex mobility tasks.

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“…(1, 2) People with CFL almost always use a preferred retinal locus (PRL) (3, 4), an extra-foveal location near the scotoma, to fixate targets that would normally be foveally fixated (we will refer to scotoma location/direction relative to the PRL in visual field space, not in retinal directions). The scotoma is lateral to the PRL in ~65% of cases, but can be above or, rarely, below.…”

Section: Introductionmentioning

confidence: 99%