Is learning a logographic script easier than reading an alphabetic script for German children with dyslexia?

PURPOSE: Developmental dyslexia in alphabetic languages (DD) is characterized by a phonological deficit. Since logographic scripts rely predominantly on visual and morphological processing, reading performance in DD can be assumed to be less impaired when reading logographic scripts. METHODS: 40 German-speaking children (18 with DD, 22 not reading-impaired-group C; 9-11 years) received Chinese lessons. Eye movements (EM) were recorded during naming single alphabetic words, pictures (confrontational) and Chinese characters to be named in German and Chinese. The main outcome variables were: Articulation latency, numbers and durations of fixations. Quality of life (QoL) was assessed by questionnaires. RESULTS: While reading alphabetic words, articulation latencies and numbers of fixations were significantly higher for group DD than for group C (AL-DD = 1.13, AL-C = 0.84, p< .001; FN-DD = 3.50; FN-C = 2.00, p< .001). For naming pictures and Chinese characters in German and in Chinese, no significant group differences were found for any of the EM variables. The percentage of correct answers was high for German naming (DD = 86.67%, C = 95.24%; p = .015) and lower for Chinese naming in both groups, but significantly lower in group DD, especially for Chinese naming (DD = 56.67%, C: 83.77%; p = .003). QoL differed between groups from the children's perspective only at posttest. Parents of group DD perceived their children`s QoL to be lower compared with parents of group C at pre- and posttest. CONCLUSIONS: Children with dyslexia performed as well as group C during naming Chinese characters in German and in Chinese regarding their EM variables, presumably because they processed Chinese characters by the visuo-spatial pathway with direct access to the semantic system. However, the significantly lower percentage of correct answers especially during Chinese naming showed that group DD had more difficulties naming Chinese characters than group C, which could be attributed to their phonological deficit, among other factors. TRIAL REGISTRATION: German clinical trials register (DRKS00015697).

New, diagnostic flicker test for optic neuritis shows specific stages following disease onset.

BACKGROUND: Previously, results of the digital flicker test (DFT) have shown distinct patterns in acute optic neuritis (ON) and healthy eyes. We aimed to examine the diagnostic potential of the DFT in acute ON and to investigate the temporal development of the DFT response following ON while comparing with visual evoked potentials (VEP). METHODS: The DFT examines the subjective brightness of a flickering field, varied in 11 different frequencies from 0 to 60 Hz, compared to a steady field. Previous studies have indicated a pronounced darkness enhancement at medial frequencies in acute ON eyes. Darkness enhancement at medial frequencies was expressed as a quantitative covariate (DFTDE). Results were compared with healthy controls and follow-up measurements were compared with VEP. RESULTS: 112 patients were examined <31 days of onset (median 14.0 days (IQR:12.25)). 104 of 112 patients showed an abnormal flicker test (sensitivity 93%). DFT was abnormal in 2 of 55 healthy controls. The DFT showed normalization in 34% at 3 months, 36.4% at 6 months and 71.4% at >8 months from ON onset compared to 13.3%, 22.4% and 28.6% for VEP. Changes to the pattern of the DFT results were shown at specific stages during and following ON. CONCLUSIONS: The DFT is an easy-to-use and sensitive diagnostic test for acute ON. The flicker test shows a more pronounced temporal evolution following ON than VEP and may be of use monitoring the course of ON.

Comparing Reading Speeds for Reading Standardized Single Sentences and Paragraphs in Patients with Maculopathy.

INTRODUCTION: The purpose of this study was to compare reading speeds (RS) of either paragraphs of text or single sentences in patients with maculopathy by investigating the repeatability of RS to decide which text type to use in studies on patients with maculopathy. METHODS: RS was measured for standardized texts in 25 participants with a central scotoma due to maculopathy (mean age 77.8 years ± 9.9 SD, mean binocular visual acuity 0.65 logMAR (±0.85 SD), median magnification requirement 3-fold). Reading 3 single sentences taken from the Radner reading charts (sample #1, #2, and #3) of 14 words and reading 3 paragraphs of International Reading Speed Texts (IReST, sample # 3, #6, and #10) with a mean of 132 (±3.2 SD) words, each in German, were compared. The 6 texts were read aloud in random order from a closed-circuit TV system, with size adjusted according to the individual magnification requirement. Reading time was measured by stopwatch, and speed was calculated in correctly read words per minute (wpm). Differences in RS depending on text length (single sentence vs. paragraph) and text sample were calculated by the Bland-Altman analysis. RESULTS: The mean RS showed no significant difference between 2 charts of the same kind (sentences: 93 wpm ± 37 SD; paragraphs: 95 wpm ± 38 SD). RS differences between 2 charts were lower in paragraphs than in single sentences. Highest correlations of RS between all 6 texts existed between the 3 IReST text samples (r = 0.98, 0.98, and 0.98) compared with the 3 Radner sentences (r = 0.89, 0.81, and 0.90). The inter-chart reliability (coefficient of repeatability) was smaller for the paragraphs (12.9 wpm) than for the single sentences (36.4 wpm). CONCLUSION: In patients with maculopathy, single sentences are well suited for single measurement of RS. For repeated measurements (e.g., monitoring the course of a reading disorder or assessing effects of interventions), paragraphs are preferable because of their lower variability of RS between the paragraphs.

Sacrificing one visual hemifield during pediatric epilepsy surgery: Effects on visual search.

OBJECTIVES: To investigate early and late effects of planned surgically acquired homonymous hemianopias on visual search in children and adolescents. METHODS: This prospective study included five patients (5y 5 m-18y 0 m; 2 girls) with pharmaco-refractory epilepsies in whom one visual hemifield was sacrificed as part of the surgical strategy, and, as controls, seven patients (5y 11 m-18y 0 m; 6 girls) undergoing epilepsy surgeries not affecting the visual fields. Visual search was studied using the "Table Test", which is an everyday life-like visual search test. General processing speed was studied using a standard IQ subtest. RESULTS: All five patients with newly acquired homonymous hemianopias showed a relative disadvantage of visual search times for objects in their newly blind hemifields immediately after the surgery. Six months later, this relative disadvantage had recovered completely in all patients. Nevertheless, compared with the preoperative situation, overall search times were still prolonged in the hemianopic patients, but this effect could be mitigated or even overcompensated by improvements in processing speed. CONCLUSIONS: Children with homonymous hemianopias inflicted by epilepsy surgery develop effective compensation strategies to minimize the relative disadvantage of visual search in their blind hemifields. For changes in overall visual search times between the preoperative and the six-month follow-up examination, we could demonstrate overlapping effects of (a) deterioration by hemianopia and (b) amelioration by improved processing speed as part of the cognitive improvements achieved by amelioration of the epilepsy.

Uncovering homonymous visual field defects in candidates for pediatric epilepsy surgery.

OBJECTIVES: Perimetry in children can be challenging due to low cooperation and short attention span. Especially during the pre-surgical work-up of children with pharmaco-refractory epilepsies, however, diagnosing homonymous visual field defects (HVFDs) can be crucial for planning surgical strategies. Here, we evaluated "campimetry" for visual field testing in children. Furthermore, we analyzed strabismus and anomalous head posture as clinical signs for HVFDs. METHODS: Campimetry and a standard orthoptic examination were performed in 18 patients (age range: 3 y 2 m-18 y) who underwent epilepsy surgeries in our center during the study period, and in 11 additional patients (age range: 2 y 10 m-22 y 10 m) with suspected or confirmed HVFDs. RESULTS: In 16/18 patients of our unselected surgery cohort, pre- and postoperative campimetry was successfully completed. Of these, only 7/16 patients had intact visual fields pre- and postoperatively, while 5/16 patients already showed preoperative HVFDs and 4/16 patients suffered newly acquired HVFDs as calculated consequences of the surgery. Regarding clinical signs, strabismus (mostly esotropia) and anomalous head posture were specific indicators of HVFDs (strabismus: 6/12 with HVFDs vs 1/18 without; anomalous head posture: 8/12 with HVFDs vs 0/18 without). CONCLUSIONS: For perimetry in children with limited cooperation, we suggest campimetry as it allows early detection and fast delineation of HVFDs. This is particularly important in pediatric epilepsy surgery patients, who display a surprisingly high proportion of HVFDs (9/16). Both, strabismus and anomalous head posture can indicate such HVFDs. Therefore, clinicians should pay attention to these clinical signs, especially in the context of epilepsy surgery.

Sensitive Assessment of Acute Optic Neuritis by a New, Digital Flicker Test.

BACKGROUND: The Aulhorn flicker test (AFT) previously showed promise in diagnosing acute optic neuritis (ON) albeit with suboptimal sensitivity. A new, digitalized version of the AFT (the DFT) has not previously been examined in acute ON. OBJECTIVES: To examine the sensitivity, specificity and reproducibility of the DFT in acute ON. METHOD: The DFT assesses the subjective brightness of a flickering field (1-60 Hz). In normal subjects, brightness enhancement occurs at intermediate frequencies, whereas in acute ON darkness enhancement (DE) is hypothesized. AFT and DFT measurements were obtained in acute ON patients (≤31 days from first symptom) with DE as a quantitative covariate. Reproducibility of the DFT end point was assessed in the form of an intraclass correlation. RESULTS: 30 untreated first-time acute ON patients and 55 healthy controls were examined. AFT and DFT were performed 12.7 days (range: 4-30) following ON onset. The DFT showed a sensitivity of 0.93 (95% CI = 0.78-0.99) to a specificity of 0.96 (95% CI = 0.87-1.00). The AFT showed a sensitivity of 0.76 (95% CI = 0.56-0.90) to a specificity of 1.00 (95% CI = 0.93-1.00). No significant correlation was shown between DFT and visual acuity. The intraclass correlation of the DFT end point in healthy subjects was 0.84. CONCLUSIONS: We present a new DFT in acute ON displaying a high specificity of 0.96 and a sensitivity of 0.93. Our study indicates the DFT to be an accurate and easy-to-use tool in diagnosing acute ON, which may be especially helpful in atypical cases.

Assessing Variability in Reading Performance with the New Greek Standardized Reading Speed Texts (IReST).

SIGNIFICANCE: This article evaluates the standardized Greek version of the International Reading Speed Texts (IReST) set, which enriches interlanguage comparisons and international clinical studies of reading performance. Moreover, it investigates how specific textual and subject-related characteristics modulate the variability of reading speed across texts and readers. PURPOSE: The purpose of this study was to develop a standardized Greek version of the IReST set and investigate how specific textual and subject-related factors modulate the variability of reading speed across texts and readers. METHODS: The English IReST texts were translated to Greek and matched for length, content, and linguistic difficulty. The Greek IReSTs were presented at a distance of 40 cm and size of 1 M to assess reading speeds of 25 normally sighted native speakers (age range, 18 to 35 years). The participants read the texts aloud while reading time was measured by stopwatch. Reading performance included measurement of reading speed in three units of analysis. Reading efficiency was assessed using a word-level oral reading task. Statistical analysis included evaluation of subject- and text-related variability, as well as correlations between reading speed and specific textual and subject-related factors. RESULTS: The average reading speed between texts was 208 ± 24 words/min, 450 ± 24 syllables/min, and 1049 ± 105 characters/min. Differences between readers accounted for the 76.6%, whereas differences across texts accounted for the 23.4% of the total variability of reading speed. Word length (in syllables per word) and median word frequency showed a statistically significant contribution to the variability of reading speed (r = 0.95 and 0.70, respectively). Reading speed was also statistically correlated with word reading efficiency (r = 0.68). CONCLUSIONS: The addition of the Greek version in the IReST language pack is expected to be a valuable tool for clinical practice and research, enriching interlanguage comparisons and international studies of reading performance.

Effects of visual search training in children with hemianopia.

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.

Homonymous Hemianopia in Children and Adolescents: An MRI Study.

AIM: Diagnosing homonymous hemianopia (HH) in children can be difficult due to inability to comply with perimetry. Therefore, HH can often only be suspected by magnetic resonance imaging (MRI) showing lesions to the retrochiasmatic visual pathways. The aim of our retrospective observational cross-sectional study was to improve the radiologic detection of HH. METHODS: MRIs of 21 subjects (5-17 years old) with ophthalmologically confirmed HH (14 complete, 7 incomplete hemianopias) were analyzed. In addition, we asked four questions looking at everyday problems possibly related to the HH. The questions asked for (1) problems in avoiding objects/people, (2) bumping into objects/people, (3) difficulties in judging stairs, and (4) difficulties in grasping objects. RESULTS: We found neuroanatomical correlates of the HH in all 21 participants, with the optic radiation being involved in almost all participants (20/21). Everyday problems possibly related to the HH were reported for all nine patients with postneonatally acquired complete hemianopias. In contrast, no such problems were reported for seven patients with incomplete HH (7/7) and for 3/5 patients with complete hemianopias due to pre-, peri- or neonatally acquired brain lesions. INTERPRETATION: A dedicated radiologic analysis of the retrochiasmatic optic pathway should routinely be performed in children with brain lesions to identify children with HH. Early onset and incomplete HH are predictors for successful compensation.

Can positions in the visual field with high attentional capabilities be good candidates for a new preferred retinal locus?

The sustained component of visual attention lowers the perceptual threshold of stimuli located at the attended region. Attentional performance is not equal for all eccentric positions, leading to variations in perception. The location of the preferred retinal locus (PRL) for fixation might be influenced by these attentional variations. This study investigated the relation between the placement of sustained attention and the location of a developed PRL using simulations of central scotoma. Thirteen normally sighted subjects participated in the study. Monocular sustained attention was measured in discrete eccentric locations of the visual field using the dominant eye. Subsequently, a six degrees macular scotoma was simulated and PRL training was performed during eight ten-minutes blocks of trials. After training, every subject developed a PRL. Subjects with high attentional capabilities in the lower hemifield generally developed PRLs in the lower hemifield (n=10), subjects with high attentional capabilities in the upper hemifield developed PRLs in the upper hemifield (n=2) and one subject with similar attentional capabilities in the upper and lower hemifield developed the PRL on the upper hemifield. Analyzed individually, the results showed that 70% of the subjects had a PRL location in the hemifield where high attentional performance was achieved. These results suggest that attentional capabilities can be used as a predictor for the development of the PRL and are of significance for low vision rehabilitation and for the development of new PRL training procedures, with the option for a preventive attentional training in early macular disease to develop a favorable PRL.

Adaptation, perceptual learning, and plasticity of brain functions.

The capacity for functional restitution after brain damage is quite different in the sensory and motor systems. This series of presentations highlights the potential for adaptation, plasticity, and perceptual learning from an interdisciplinary perspective. The chances for restitution in the primary visual cortex are limited. Some patterns of visual field loss and recovery after stroke are common, whereas others are impossible, which can be explained by the arrangement and plasticity of the cortical map. On the other hand, compensatory mechanisms are effective, can occur spontaneously, and can be enhanced by training. In contrast to the human visual system, the motor system is highly flexible. This is based on special relationships between perception and action and between cognition and action. In addition, the healthy adult brain can learn new functions, e.g. increasing resolution above the retinal one. The significance of these studies for rehabilitation after brain damage will be discussed.

Eye Movement Training and Suggested Gaze Strategies in Tunnel Vision - A Randomized and Controlled Pilot Study.

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.

Measurement of reading speed with standardized texts: a comparison of single sentences and paragraphs.

PURPOSE: We examined the influence of text length (single sentence versus a paragraph of several sentences) on the repeatability of reading speed measurements in normal-sighted subjects. METHODS: We compared reading speeds for the German versions of the Radner charts (single sentences of 14 words each) and the International Reading Speed Texts (IReST) charts (paragraphs, on average 132 words) in 30 normal-sighted elderly subjects aged 51-81 years (mean 64.5 years ± 7.2 SD). Three texts each of both lengths were read aloud in random order. The influence of text length (single sentence or paragraph) and text sample (each single text) on reading speed was calculated by a regression model and Bland-Altman analysis. RESULTS: Mean reading speed (words per minute) showed no significant difference for single sentences (170 wpm ± 33 SD) and paragraphs (167 wpm ±31 SD). Differences in reading speeds within one type of reading material were higher between single sentences than between paragraphs. Correlation coefficients between speeds were higher for paragraphs (r = 0.96-0.98) than for single sentences (r = 0.69-0.78). Variations between reading speeds for three texts of each length were markedly lower for paragraphs than for single sentences: (median, interquartile range [IQR]): 6.7, IQR 13.9; 3.0, IQR 8.3; -2.0, IQR 9.7 versus -8.8, IQR 29.6; 15.6, IQR 29.4; 22.7, IQR 19.4, respectively. CONCLUSIONS: Since reading speeds assessed with paragraphs show lower variance among texts than those for single sentences, they are better suited for repeated measurements, especially for long-term monitoring of the course of reading performance and for assessing effects of interventions in subjects with reading disorders.

Eye movements during saccadic and fixation tasks in patients with homonymous hemianopia.

BACKGROUND: The aim of our study was to quantify ocular motor performance in patients with homonymous hemianopia and in healthy controls during saccadic and fixation tasks and to detect potential spontaneous adaptive mechanisms in the hemianopic patients. METHODS: Eye movements were recorded in 33 hemianopic patients (15 right, 18 left; disease duration, 0.2-29 years) and 14 healthy subjects by scanning laser ophthalmoscope allowing determination of the absolute fovea position relative to the stimulus without calibration. Landing accuracy of saccades was determined for 5° saccades, indicated by the number of dysmetric saccades (DS), and fixation stability (FS) after landing. In addition, during continuous fixation of a central cross, FS, and distribution of fixational eye movements (FEMs) were measured. Size of macular sparing was determined using custom microperimetry software (stimulus grid, 0.5°). RESULTS: Compared with controls, landing accuracy was decreased in hemianopic patients, indicated by significantly more DS (hypometric and hypermetric) to the blind side compared with the seeing side. The number of DS was greater in patients with macular sparing of <4°. DS were not correlated with age and disease duration. FS after landing was lower after saccades to the blind side. Distribution of FEM during continuous fixation was asymmetrically shifted to the blind side, especially in cases of macular sparing of <4°. CONCLUSIONS: Number of DS was not correlated with disease duration indicating insufficient spontaneous long-term adaptation. Increased number of DS and decreased FS after landing in patients with small or absent macular sparing stresses the importance of intact parafoveal vision. Asymmetric FEMs during continuous fixation indicate an advantageous adaptive mechanism to shift the visual field border towards the hemianopic side.

Evaluation of fixation pattern and reading ability in patients with Leber hereditary optic neuropathy.

BACKGROUND: Leber hereditary optic neuropathy (LHON) is characterized by progressive loss of central vision leading to impaired reading ability. The aim of this study was to evaluate sensory adaptation and reading ability in LHON patients. METHODS: This prospective pilot study included 12 male patients with a clinical diagnosis and a positive genetic analysis of LHON, who matched the inclusion criteria of a central scotoma on visual field testing and the use of magnifying aids to read. Examination included best-corrected visual acuity, magnification need, reading speed, and evaluation of fixation by corneal reflexes and by Rodenstock scanning laser ophthalmoscope (SLO). Central scotoma was assessed by conventional perimetry (Tübingen Automated Perimeter) and microperimetry (NIDEK MP1). RESULTS: Mean magnification need was 13.2 ± 7.3-fold (range: 2- to 25-fold). Mean reading speed was 53 ± 18 words per minute (WPM) (range: 24-85 WPM). With automated perimetry, all patients showed central scotomas with a mean radius of 13° ± 7° (range: 1°-30°) in the better eye. Microperimetry in all patients showed fenestrated central scotomas. Eccentric fixation with a preferred retinal locus (PRL) was detected with SLO examination and microperimetry correlated well in 11 of 12 patients. The SLO results showed no systematic pattern in the placement of the PRL; however, 7 of 12 patients (58%) placed their PRL in an unfavorable location left or below the fovea. In 8 of 12 patients, fixation was unstable. Between reading speed and central scotoma size, there was a statistically significant negative correlation (P = 0.021, r = -0.65). CONCLUSIONS: The percentage of unfavorable PRL locations was extremely high compared with other disorders with central scotomas. Unstable fixation and fenestrated central scotomas led to difficulties in reading. Early rehabilitation and, if necessary, eccentric viewing training should be considered in LHON patients.

Standardized assessment of reading performance: the New International Reading Speed Texts IReST.

PURPOSE: There is a need for standardized texts to assess reading performance, for multiple equivalent texts for repeated measurements, and for texts equated across languages for multi-language studies. Paragraphs are preferable to single sentences for accurate speed measurement. We developed such texts previously in 6 languages. The aim of our current study was to develop texts in more languages for a wide range of countries and users, and to assess the reading speeds of normally-sighted readers. METHODS: Ten texts were designed for 17 languages each by a linguist who matched content, length, difficulty, and linguistic complexity. The texts then were used to assess reading speeds of 436 normally-sighted native speakers (age 18-35 years, 25 per language, 36 in Japanese), presented at a distance of 40 cm and size 1 M, that is 10-point Times New Roman font. Reading time (aloud) was measured by stopwatch. RESULTS: For all 17 languages, average mean reading speed was 1.42 ± 0.13 texts/min (±SD), 184 ± 29 words/min, 370 ± 80 syllables/min, and 863 ± 234 characters/min. For 14 languages, mean reading time was 68 ms/character (95% confidence interval [CI] 65-71 ms). Our analysis focussed on words per minute. The variability of reading speed within subjects accounts only for an average of 11.5%, between subjects for 88.5%. CONCLUSIONS: The low within-subject variability shows the equivalence of the texts. The IReST (second edition) can now be provided in 17 languages allowing standardized assessment of reading speed, as well as comparability of results before and after interventions, and is a useful tool for multi-language studies (for further information see www.amd-read.net).

Rehabilitative techniques.

This chapter deals with neuro-ophthalmological diseases at different levels of the afferent visual pathways with special regard to visual field defects, their functional impact, and their rehabilitation. The nature of these impairments and their significance for activities of daily living can be quite varied; an exact assessment of the residual function is required to determine specific rehabilitation approaches. Rehabilitation aims to compensate for the visual deficits by means of specific training and visual aids. Visual field defects in the center cause reading disability. Preconditions for reading are a sufficient size of the reading visual field or perceptual span and sufficient resolution of the retinal area used for reading. In central scotoma, as in macular or optic nerve disease, reading ability can be regained by eccentric fixation plus text magnification. In hemianopia, reading depends on the amount of sparing in the center, the side of the defect, and adaptive strategies. Field defects in the periphery cause orientation and mobility problems. In constricted fields, tactile training with a cane is indicated; in hemianopia, explorative saccadic training is effective. With the appropriate technique, rehabilitation can be very successful, and quality of life can be regained in most patients.

Training to improve reading speed in patients with juvenile macular dystrophy: a randomized study comparing two training methods.

PURPOSE: In this study, we examined the clinical application of two training methods for optimizing reading ability in patients with juvenile macular dystrophy with established eccentric preferred retinal locus and optimal use of low-vision aids. METHOD: This randomized study included 36 patients with juvenile macular dystrophy (35 with Stargardt's disease and one with Best's disease). All patients have been using individually optimized low-vision aids. After careful ophthalmological examination, patients were randomized into two groups: Group 1: Training to read during rapid serial visual presentation (RSVP) with elimination of eye movements as far as possible (n = 20); Group 2: Training to optimize reading eye movements (SM, sensomotoric training) (n = 16). Only patients with magnification requirement up to sixfold were included in the study. Training was performed for 4 weeks with an intensity of ½ hr per day and 5 days a week. Reading speed during page reading was measured before and after training. Eye movements during silent reading were recorded before and after training using a video eye tracker in 11 patients (five patients of SM and six of RSVP training group) and using an infrared reflection system in five patients (three patients from the SM and two patients of RSVP training group). RESULTS: Age, visual acuity and magnification requirement did not differ significantly between the two groups. The median reading speed was 83 words per minute (wpm) (interquartile range 74-105 wpm) in the RSVP training group and 102 (interquartile range 63-126 wpm) in the SM group before training and increased significantly to 104 (interquartile range 81-124 wpm) and 122, respectively (interquartile range 102-137 wpm; p = 0.01 and 0.006) after training, i.e. patients with RSVP training increased their reading speed by a median of 21 wpm, while it was 20 wpm in the SM group. There were individual patients, who benefited strongly from the training. Eye movement recordings before and after training showed that in the RSVP group, increasing reading speed correlated with decreasing fixation duration (r = -0.75, p = 0.03), whereas in the SM group, increasing reading speed correlated with a decreasing number of forward saccades (r = -0.9, p = 0.01). CONCLUSION: Although the median effect of both training methods was limited, individual patients benefited well. Our results may indicate a difference in the training effect between both methods on the reading strategy: the RSVP method reduces fixation duration, the SM method decreases the number of forward saccades. Patients can apply their newly learned reading strategy in the natural reading situation, e.g. in page reading without special presentation of the text. These results can be used as a basis for further improvement in training methods for optimizing reading performance in patients with a central scotoma.