Braille is a haptic modality based on a system of raised dots to represent text. Analogously to eye movements in visual reading, braille readers move the reading hand(s) over the printed material to acquire text. In contrast to visual reading, bimanual braille reading raises the question of each hand’s contributing role, and the possibility of perceptual mechanisms distinct from visual reading. Here we analyzed the hand movement patterns of blind braille readers in order to examine the relationship between reading style, hand kinematics, and reading speed. Participants read standardized IReST text passages aloud while their hand movements were recorded with a specialized tracking system. Preliminary results suggest that reading styles strongly affected hand kinematics and performance. Participants who used a more independent hand movement style (e.g. scissors) completed trials faster on average than those who used more interdependent style (e.g. parallel or left marks). These styles were also characterized by lower intermanual correlation in kinematic markers such as regressive movements. In addition, we found that scissors-style readers were disproportionately likely to exhibit simultaneous disjoint reading, in which the two hands read different parts of the text in parallel. Notably, this suggests a neural “memory buffer” mechanism distinct from visual print or serial braille reading, as input acquired in parallel is sorted on the fly to reconstruct a serial text stream. Taken together, our results quantitatively support previous work suggesting that the ability to use independent hand movements may be an important factor in the development of efficient braille reading skills. While further research is needed to fully understand the mechanisms underlying these effects, our results provide new insights into the benefits of bimanual braille reading strategies and may have implications for the teaching of braille to blind individuals.

The most direct view is that particular voltage deflections reflect separate brain processes. With visual evoked potentials, however, one might expect to obtain a greater correlation with neurophysiological processes, especially with the emergence of extensive anatomical, physiological, and psychophysical data on the visual system. A powerful way to describe the visual system's sensitivity to pattern stimulation is to obtain the spatial frequency sensitivity curve. The apparent discrepancy can be resolved by assuming that the observer's sensitivity is due to the upper envelope of sensitivities of separate mechanisms, each sensitive to a relatively narrow range of spatial frequencies and spanning a range of frequencies. For all experiments, the authors presented vertical sinusoidal gratings on an oscilloscope screen. The preceding results raise the hope that with an appropriate animal model, particular components of the VEP might be linked to physiologically and anatomically determined classes of neurons in monkey visual cortex.

It is well known that people who read print or braille sometimes make eye or finger movements against the reading direction. The way these regressions are elicited has been studied in detail by manipulating linguistic aspects of the reading material. Actually, it has been shown that reducing the physical intensity or clarity of the visual input signal can also lead to increased regressions during reading. We asked whether the same might be true in the haptic realm while reading braille. We set the height of braille dots at three different levels (high, medium, and low) and asked adult blind, practiced braille readers to read standardized texts without any repetition of content. The results show that setting the braille dot height near the tactile threshold significantly increased the frequency of regressive finger movements. Additionally, at the lowest braille dot height, braille reading speed significantly diminished. These effects did not occur at braille dot heights that were closer to the height of standard braille (medium and high). We tentatively conclude that this effect may be due to a heightened sense of uncertainty elicited by perception near the threshold that seems to be common to the reading process, independent of the sensory input modality. Furthermore, the described effect may be a feature of a brain area that contributes to the reading process mediated by vision as well as touch.

Background This study investigates the effect of a new computer-based visual search training (VST) that was adapted for children with homonymous hemianopia (HH). Methods 22 children with HH (median age 11 years, 8 months: 6y6m-19y2m) trained at home for 15 minutes twice/day, 5 days/week, for 6 weeks. To assess performance before training (T1), directly after training (T2) and 6 weeks after the end of training (T3), we measured search times (STs) during on-screen search (with eye tracking), and in a real life search task. Additional variables analyzed during on-screen search were numbers, amplitudes, and durations of saccades, their directional patterns and the proportional number of saccades into the non-seeing field. The latter was the main variable during free viewing. Sixteen healthy age-matched children, who did not undergo the training, served as comparison group. Quality of Life (QoL)-questionnaires were also applied. Results STs of the patients decreased significantly during the training and all search performance tests. This improvement persisted 6 weeks after the end of the training. Saccade amplitudes increased, total number of saccades to find the target decreased, and the proportional number of saccades to the non-seeing side increased. These changes were maintained at T3. Saccade durations did not change. During free viewing, saccades were equally distributed to both sides before and after training. Patients reported improvements in QoL and activities of daily living. Performance in the healthy children did not change by simply repeating the visual search test. Conclusions The improvement in STs in all search tasks, larger and fewer saccades, and an improved search strategy after VST suggests that the children with HH benefited from the training. The maintained improvement at T3 and the improvement in the real life search task indicate that the newly developed search strategy persists and can be applied to everyday life.

Die Leseleistung, welche mit Lesetests gemessen werden kann, ist davon abhängig, ob Lesematerial mit oder ohne syntaktischen Zusammenhang verwendet wird.

PURPOSE:The goal was the validation of the Macular Mapping Test (MMT) for clinical use. We studied its susceptibility to blur caused by refractive errors and its test-retest reliability.METHODS:We tested letter recognition in 33 target locations in the central visual field (10° radius) at two contrast levels, 10 and 100 per cent. Healthy subjects were either young (mean: 25.7 years) or elderly (mean: 67.0 years). A third group (patients with age-related macular degeneration, mean age: 76.4 years) were tested with their habitual optical correction and subsequently with optimal correction. The influence of refractive errors on performance was measured only for the healthy subgroups. All visual acuities were measured at 6.0 and 0.4 metres. Outcome measure was the 'general field score' (GFS), a single number expressing the overall level of letter recognition performance.RESULTS:The general field score versus refractive error showed a mean loss of 3.9 points per dioptre and 5.9 points per dioptre in young subjects at 100 and 10 per cent contrast, respectively. In elderly subjects, mean losses were 2.6 points per dioptre and 5.5 points per dioptre for 100 and 10 per cent contrast, respectively. The general field score ratio (GFS at 10 per cent divided by GFS at 100 per cent) shows a decrease of eight per cent for the young group and 11 per cent for the elderly group. Performance increased after improvement of the refractive status in the AMD group: At 100 per cent contrast, the general field score increase from 21.5 to 24.1 (p < 0.008) was significant but not at 10 per cent contrast. Mean increase of acuity with the optimal correction was 0.32 to 0.46 decimal for distance (p = 0.018) and 0.28 to 0.44 decimal near (p = 0.018). Test-retest reliability was good but dependent on contrast.CONCLUSIONS:At both contrasts, performance declined with increasing blur caused by refractive errors. The slope of this decline is more pronounced at the lower contrast. In healthy subjects, optical blur beyond 1.00 D can cause significant performance losses.

BACKGROUND:Reading performance that can be measured by reading tests depends on whether reading material with or without contextual continuity is used. OBJECTIVE:The goal of this study was to create a German version of the SKread test and to evaluate it in a clinical setting. MATERIAL AND METHODS:The evaluation of the SKread test was first performed on two groups of visually healthy subjects of different ages: a junior group of 25 persons with ages between 20 and 30 years (mean = 25.84 years, SD ± 2.41 years) and a senior group of 25 persons with ages between 51 and 84 years (mean = 62.40 ± 8.46 years). The same measurements were also performed on a group of 18 patients with age-related macular degeneration (AMD) with ages between 75 and 95 years (mean = 81.89 ± 5.48 years). The reading performance was also measured using Radner charts. RESULTS:Using reading material without syntactic continuity considerably slowed down the reading speed and increased the error rate. Median reading rates of 11.53 characters/s (CPS) for the junior group and 8.96 CPS for the senior group were clearly lower than those for the Radner charts (22.02 CPS and 18.48 CPS, respectively). In the AMD patients, a statistical analysis of the error rates showed a highly significant difference between the Radner charts and the SKread test (p = 0.00014). Furthermore, by analyzing the errors made in the SKread test information could be obtained about the position of central scotomas. The test-retest reliability of the SKread was very good. CONCLUSION:Information about the position of a central scotoma can be acquired by using the SKread test and an analysis of reading errors, which can augment effective clinical monitoring in AMD and subsequent visual rehabilitation.

PURPOSE:Degenerative retinal diseases, especially retinitis pigmentosa (RP), lead to severe peripheral visual field loss (tunnel vision), which impairs mobility. The lack of peripheral information leads to fewer horizontal eye movements and, thus, diminished scanning in RP patients in a natural environment walking task. This randomized controlled study aimed to improve mobility and the dynamic visual field by applying a compensatory Exploratory Saccadic Training (EST).METHODS:Oculomotor responses during walking and avoiding obstacles in a controlled environment were studied before and after saccade or reading training in 25 RP patients. Eye movements were recorded using a mobile infrared eye tracker (Tobii glasses) that measured a range of spatial and temporal variables. Patients were randomly assigned to two training conditions: Saccade (experimental) and reading (control) training. All subjects who first performed reading training underwent experimental training later (waiting list control group). To assess the effect of training on subjects, we measured performance in the training task and the following outcome variables related to daily life: Response Time (RT) during exploratory saccade training, Percent Preferred Walking Speed (PPWS), the number of collisions with obstacles, eye position variability, fixation duration, and the total number of fixations including the ones in the subjects' blind area of the visual field.RESULTS:In the saccade training group, RTs on average decreased, while the PPWS significantly increased. The improvement persisted, as tested 6 weeks after the end of the training. On average, the eye movement range of RP patients before and after training was similar to that of healthy observers. In both, the experimental and reading training groups, we found many fixations outside the subjects' seeing visual field before and after training. The average fixation duration was significantly shorter after the training, but only in the experimental training condition.CONCLUSIONS:We conclude that the exploratory saccade training was beneficial for RP patients and resulted in shorter fixation durations after the training. We also found a significant improvement in relative walking speed during navigation in a real-world like controlled environment.

PURPOSE:To evaluate the use of SKread, a vision test based on random word sequences that prevents the prediction of upcoming words by linguistic criteria and is simple to score in a clinical setting.METHODS:SKread combines the standardized format of the MNread test with sequences of random words and letters like the Pepper Visual Skills for Reading test. A total of 231 subjects (aged 16 to 97 years) participated. We report data from 136 eyes of subjects with a maculopathy and 65 with normal or near-normal vision. Test reliability was investigated on an additional 30 eye-healthy subjects. We tested visual acuity and reading performance for continuous text and random words monocularly. Reading speed and all errors made are reported.RESULTS:Reading speed was always higher for continuous text than for random word sequences, even in normally sighted subjects for whom the median reading times per paragraph were 2.4 s (MNread) vs. 6.8 s (SKread). In patients with maculopathies, the medians were 4.2 s vs. 12.25 s. These differences were statistically significant. Number and type of errors made depended only negligibly on age and visual acuity. Patients with a dense scotoma right of fixation made more "right errors" by missing letters at the end of words, whereas those with a scotoma left of fixation made more "left errors" by missing letters at the beginning of words. The SKread test showed good test-retest repeatability.CONCLUSIONS:The unpredictability of random word and letter sequences renders reading performance highly dependent on eyesight and less dependent on reading skill and educational level. Recurrent right or left errors can indicate the presence and location of a scotoma without expensive equipment. This knowledge can be used to teach patients about how the scotoma can interfere with their vision.

Objective: The standard measure for the assessment of functional vision in the central retina is best corrected visual acuity (VA). Our aim was to investigate whether it is an advantage to include tests for functional changes in the near retinal periphery to monitor treatment effects in patients receiving multiple injections of anti vascular endothelial growth factor (anti-VEGF) agents for advanced exudative age-related macular degeneration (AMD).Design: Prospective pilot study.Participants: Our cohort consisted of 24 patients with exudative AMD (mean age +/- SD: 77.46 +/- 7.82 years) treated at an ophthalmology clinic.Methods: We compared data from standard functional measurements, VA-near, and contrast sensitivity (CS), with results from the macular mapping test (MMT) at 10% and 100% contrast. Measurements of retinal thickness by optical coherence tomography (OCT) were used to document the morphologic efficacy of the anti-VEGF agent. Tests were performed at baseline and 4 weeks after 3 monthly ranibizumab injections.Results: All 4 functional tests yielded successes (equal or better visual performance after treatment) in 79.2% to 83.3% of cases. Including test locations in the near periphery yielded the highest success rate in the MMT at 10% contrast. Values for VA-near and CS also improved in a majority of cases. OCT measurements of retinal thickness indicated that the agent was effective in the fovea and near periphery.Conclusions: Our findings indicate that using the MMT adds information about functional changes in the near periphery of the retina and allows more sensitive assessment of treatment effects or disease progression without the high expense of other techniques.

PURPOSE:To introduce a novel approach to topographic function assessment in visual impairment that requires neither fixation nor reading.METHODS:One hundred thirty-five consecutive low vision patients with varying diagnoses and 30 control subjects of comparable median age participated. Performance was measured in a search task that required finding and identifying visual targets which appeared consecutively on a monitor in 32 locations of the central field of gaze. The task specifically discourages steady fixation and the subjects could make eye movements as needed to locate targets. Target size was always double the size threshold, and no manual action was required. The best attainable reading speed at any size was routinely measured (MNread). Main outcome measure was response latency necessary to solve the task. Data were median latencies and sums of all latencies.RESULTS:Measurements yielded a wide variety of performance levels, with a factor of 14 to 16 between best and worst performers. The highest correlation existed between median response latency in the search task and best attainable reading speed. Only a weak correlation was found between performance and visual acuity. No statistically significant correlations were found with age or diagnosis.CONCLUSIONS:The "search-and-identify" paradigm and continuous text reading share an important mechanism that determines performance in both tasks. The authors hypothesize that the factor enabling patients to perform well in both paradigms is oculomotor skill and/or eye movement strategy. Results show that the search test is a useful tool for the easy assessment of impaired vision independent of language, level of literacy, and reading habits.

By moving through the environment, an observer generates flow field patterns from which information about the movement's speed and trajectory can be extracted. Onset of peripheral object motion or a change of object motion direction disturbs this observer-generated flow field by producing a relative motion stimulus. Can relative motion in the near and far periphery of the visual field act as a cue to attract visuo-spatial attention? How powerful is such a relative motion cue (RMC) in comparison with conventional cueing with a ring-shaped frame? At 20, 30, 40, and 60 degrees eccentricity, we tested the performance of 10 subjects in a near-threshold, 4-afc Gabor orientation discrimination task without vs. with a briefly appearing ring-shaped cue attracting attention to the target location. In the second part of the study, the Gabor gratings were embedded in a random-dot flow field, and subjects performed the same task as above after presentation of a RMC (a group of random dots moving in the direction opposite from that of the flow-field) compared to a baseline without the RMC. Both types of cues induced a significant improvement of discrimination performance at all test locations. The RMC effect was stronger at more eccentric positions while the ring-shaped cue had a more pronounced effect closer to the center. Thus RMC is at least as powerful attracting attention as conventional spatial cueing. Our data point to the special role of peripheral vision in motion processing. The results have high practical relevance for tasks involving navigation and mobility.