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Purpose: To test the intra- and intersubject reproducibility of brain activation patterns that underlie visually guided saccades and word recognition in normally sighted subjects and patients with macular degeneration using functional magnetic resonance imaging (fMRI)., Methods: Ten normally sighted subjects and five patients with macular degeneration were asked to perform two visually guided saccade tasks and two word-recognition tasks during fMRI with behavioral monitoring. The fMRI measurements were repeated three times at intervals of at least 4 weeks between sessions. The intrasubject reproducibility of the brain activation patterns was examined in a model-independent manner by comparing the distributions of activation across the frontal, parietal, temporal, and occipital brain lobes using Intraclass Correlation Coefficients (ICCs). Intersubject reproducibility was examined by repeated-measure ANOVA. Results. Control subjects showed overall higher intrasubject reproducibility of brain activation patterns (75% ICCs > 0.5) than that of patients with macular degeneration (56% ICCs > 0.5). The intrasubject reproducibility for the patients improved when the target location was fixed, as in the word-recognition tasks (75% ICCs > 0.5), compared with the visually saccade tasks (37% ICCs > 0.5). Intersubject variability of brain activation patterns was strikingly high for both the control and patient groups., Conclusions: The fMRI method can serve as a reliable within-subjects measure of brain activation that has potential for measuring longitudinal changes in brain networks associated with rehabilitation training. Striking intersubject variability reflected at the level of lobes of the brain among control subjects with similar behavioral performance, suggests individual analysis is necessary when implementing longitudinal brain activation studies.

Purpose: To quantify the effects of three vision rehabilitation training approaches on improvements in reading performance., Methods: Thirty subjects with AMD participated in the training portion of the study. The median age of the subjects was 79 years (range, 54-89 years). The three training modules were: Visual Awareness and Eccentric Viewing (module 1), Control of Reading Eye Movements (module 2), and Reading Practice with Sequential Presentation of Lexical Information (module 3). Subjects were trained for 6 weekly sessions on each module, and the order of training was counterbalanced. All subjects underwent four assessments: at baseline and at three 6-week intervals. Reading performance was measured before and after each training module. A separate group of 6 subjects was randomly assigned to a control condition in which there was no training. These subjects underwent repeated assessments separated by 6 weeks., Results: Reading speeds decreased by an average of 8.4 words per minute (wpm) after training on module 1, increased by 27.3 wpm after module 2, and decreased by 9.8 wpm after module 3. Only the increase in reading speed after module 2 was significantly different from zero. Sentence reading speeds for the control group, who had no reading rehabilitation intervention, was essentially unchanged over the 18 weeks (0.96 ± 1.3 wpm)., Conclusions: A training curriculum that concentrates on eye movement control increased reading speed in subjects with AMD. This finding does not suggest that the other rehabilitation modules have no value; it suggests that they are simply not the most effective for reading rehabilitation.

To investigate the relationship between depression and quantitative measures of visual function, we recruited 18 subjects with central scotomas from macular degeneration who were enrolled in a reading rehabilitation program. Psychological batteries and reading assessments were administered prior to rehabilitation; reading assessments and a measure of adaptation to vision loss were administered following rehabilitation. We investigated relationships between reported levels of depressive symptoms and reading and adaptation outcome measures by using Pearson product moment correlation analysis. Results revealed a significant relationship between depression levels and reading acuity difference scores (r(16) = 0.54, p = 0.02) and changes in adaptation to vision loss levels (r(16) = 0.62, p = 0.01), suggesting that those who reported greater depressive symptoms did not respond as well functionally to reading rehabilitation but reported greater improvement in levels of adaptation to vision loss following rehabilitation. Future research should focus on defining standard methods to assess and remediate depression as part of the rehabilitation process.

Purpose: To compare the cortical networks that underlie word recognition and processing in patients with age-related macular degeneration (AMD) with those of normally sighted control subjects using functional magnetic resonance imaging (fMRI)., Methods: Six patients with bilateral geographic atrophy who were using an eccentrically located preferred retinal location were recruited. Six younger and six older control subjects were also recruited. Patients and control subjects were asked to perform a three-letter (3Let) and a six-letter (6Let) word recognition task during fMRI on a 3.0-Tesla MRI scanner. The fMRI tasks were two-condition, blocked-design paradigms in which central fixation was alternated with a word recognition task requiring a forced, two-choice reaction time living/nonliving judgment., Results: When contrasted with controls, patients showed increased brain activation in a widespread cortical network that included regions identified as the frontal eye fields, both superior and inferior parietal lobules, and regions within the prefrontal cortex. Peak activation within these prefrontal regions was correlated with increased accuracy (r = 0.875, P = 0.024; r = 0.848, P = 0.033) and decreased reaction times (r = -0.861, P = 0.028; r = -0.842, P = 0.036) for the 3Let task within the group of patients. Correlations between peak activity and behavioral performance were also found in both the right (-0.818, P = 0.047) and left (r = -0.839, P = 0.037) superior parietal lobules for the 3Let task. Similar relationships were found for the 6Let task., Conclusions: Patients with AMD demonstrate increased prefrontal and parietal activation compared with controls. The authors posit that these increases reflect increased top-down involvement in basic word recognition to compensate for decreased sensory function.

Purpose: To compare the cortical networks that underlie oculomotor function in patients with age-related macular degeneration (AMD) with those in normally sighted control subjects, using functional magnetic resonance imaging (fMRI)., Methods: Six patients with bilateral geographic retinal atrophy due to AMD (age range, 55-83 years) were recruited for the study. The visual acuities of the patients ranged from 20/76 (0.58 logMAR) to 20/360 (1.26 logMAR). An additional six younger (age range, 22-31 years) and six older (age range, 54-78 years) normally sighted individuals were recruited as control subjects. fMRI data were acquired on a 3.0-Tesla, scanner while subjects performed visually guided saccade (VGS) and smooth-pursuit (SmP) tasks., Results: Contrasts between VGS and fixation on a stationary target identified a network of activation that included the frontal eye fields (FEFs), supplementary eye fields (SMA/SEFs), prefrontal cortex (PFC), intraparietal sulci (IPS), and the areas of the visual cortex (MT/V5, V2/V3, and V1) in control subjects and patients. A similar network was identified for comparisons between SmP and periods of fixation. Marked variability was observed in the performance of both tasks across all patients. For both tasks, the patients generally showed increased PFC and IPS activation, with decreased activation in visual cortex compared with the control subjects. The patients showed significantly increased activation of the FEFs and SMA/SEFs in the SmP task, compared with the control subjects., Conclusions: These data suggest that performance of both eye movement tasks required greater involvement of the cortical regions generally implicated in attention and effort in patients with AMD.

Purpose: To quantify the extent of visual function losses in patients with North Carolina Macular Dystrophy (NCMD) and to demonstrate the importance of accounting for eccentric fixation when making comparisons with normal data., Methods: Five patients with NCMD who were from a single family were examined. Multifocal electroretinograms (mfERGs) and psychophysical assessments of acuity and luminance visual field sensitivities were measured throughout the central retina. Comparisons of responses from equivalent retinal areas were accomplished by shifting normal templates to be centered at the locus of fixation for each patient., Results: Losses of psychophysically measured visual function in patients with NCMD extend to areas adjacent to the locations of visible lesions. The multifocal ERG amplitude was reduced only within the area of visible lesion. Multifocal ERG implicit times were delayed throughout the entire central retinal area assessed., Conclusions: ERG timing is a sensitive assay of retinal function, and our results indicate that NCMD has a widespread effect at the level of the mid and outer retina. The findings also demonstrated that it is necessary to account for fixation locus and to ensure that equivalent retinal areas are compared when testing patients with macular disease who have eccentric fixation.

Purpose: To determine whether training oculomotor control, without direct practice in reading sentences, could increase reading speed in patients with age-related macular degeneration (AMD)., Methods: Sixteen patients with AMD participated in the study (age range, 65-87 years; mean, 77). The training program consisted of a series of exercises that were designed to allow the patients to practice eye movements. At the beginning of training, the subjects practiced small horizontal saccades in response to cognitively easy stimuli (e.g., dots). The training then progressed to practicing larger eye movements and then to practicing saccades with single letters, pairs of letters, and three-letter words. Reading of sentences was practiced in only one exercise, during the last session of the 8-week training., Results: The difference between average reading speeds before and after training was 24.7 wpm (difference between medians, 17.9 wpm). The increase in speed was statistically significant (Wilcoxon signed rank test = 124.0, P < 0.001). There was no significant relationship between change in maximum reading speed and ETDRS (Early Treatment Diabetic Retinopathy Study) acuity (r = -0.14, P = 0.76) or between change in maximum reading speed and age (r = 0.25, P = 0.45)., Conclusions: The results indicate that a training curriculum that concentrates on eye-movement control can increase reading speed in patients with AMD. This finding is especially interesting, because the training involved little direct practice in reading sentences but instead concentrated on having subjects practice control of eye positions and eye movements.

Purpose: Previous studies indicated abnormal development of fixation toward the optic nerve head in patients with the inherited retinal disease North Carolina macular dystrophy (NCMD). The implication of this development on functional vision and structural characteristics has not been described., Methods: The anatomical characteristics of five NCMD-affected individuals were assessed by measuring the retinal thickness of the macula using optical coherence tomography. The underlying physiologic health of the retina was assessed using the multifocal ERG. Psychophysical assessment of remaining vision in the affected areas was done with a new microperimetry system that measures functional visual acuity at 27 discrete locations and the Humphrey visual field analyzer., Results: All patients had better areas of visual sensitivity toward the nasal macula. Follow-up examination showed no changes in the clinical appearance of the retina. Visual acuities ranged from -0.10 logMAR (Snellen equivalent, approximately 20/16) to 0.50 logMAR (Snellen equivalent, approximately 20/63) in the better eye. No significant changes in visual acuity were found over time. Local multifocal electroretinogram deficits were found in all patients. Patients with grade 2 or 3 disease had large patches of decreased amplitudes and delayed implicit times. Results of the anatomical, electrophysiological, and psychophysical tests were consistent., Conclusion: The electrophysiological and psychophysical deficits found in patients with more severe disease were consistent with an abnormal development of fixation from the anatomical fovea toward the optic nerve head with the placement of the lesion temporal to fixation (into the nasal visual field).

Aims: To ascertain the level of perceived difficulty experienced by patients with central vision loss due to juvenile macular dystrophies in the performance of everyday activities. A second objective was to compare their perceived difficulty with that of patients with retinitis pigmentosa (RP) with primarily peripheral vision loss., Methods: 72 patients with Stargardt disease, cone dystrophy, or cone-rod dystrophy who had visual acuities worse than 20/40 and normal peripheral visual fields rated themselves on their difficulty in the performance of 33 activities encompassing a wide variety of everyday tasks. These findings were compared with the responses of 120 patients with typical RP or Usher syndrome type 2 who had visual acuities of 20/40 or better and peripheral visual field loss., Results: The juvenile macular dystrophy group reported the greatest level of overall self perceived difficulty with activities involving central vision, and lesser and variable degrees of difficulty with items within the mobility, negotiating steps, driving, and miscellaneous categories. Consistent with these findings, there were highly significant correlations between subjects' rated performances of activities involving central vision and the clinical measures of vision, including visual acuity and size of central scotoma. There were fewer significant correlations between perceived performance of activities in the other categories and the clinical measures. In general, those activities that showed significant correlations with the clinical measures of vision for the patients with juvenile macular dystrophies also showed significant differences in the patterns of responses between the juvenile macular dystrophy group and the RP group. Those items which were not correlated with the clinical measures in the juvenile macular dystrophy group tended not to show significant differences in the response patterns between the two groups., Conclusion: These results provide insight into the types of perceived difficulties in performing tasks of everyday life in patients with these disorders which affect counselling of these patients.

Purpose: The purpose of this study was to gain information about the employment status of legally blind patients., Methods: Fifty-two patients with one of four juvenile-onset macular dystrophies or achromatopsia responded to questions about their employment histories and their psychological well-being. Results from the questionnaire were analyzed using z-tests for differences in proportions or t-tests for differences in means., Results: Forty-eight percent of the patients reported that they were employed and 52% that they were not employed. The subgroup that was not employed had a significantly higher proportion of women than men, whereas the employed group had approximately equivalent proportions of men and women. The employed subgroup reported that their success at work was due to social support. This subgroup had significantly higher household incomes, was significantly less likely to collect disability-income benefits, had significantly higher educational levels, had significantly higher positive affect, and had significantly lower negative affect than the subgroup that was not employed. A logistic regression analysis indicated that education was the primary predictor of employment., Conclusion: Analysis supports the conclusion that it is beneficial for legally blind individuals to obtain an optimal level of education and receive suitable social support to facilitate their successful employment.

Objective: To determine the effects of age and central vision loss on driving skills., Methods: Ten subjects with age-related macular degeneration and average binocular visual acuity of 20/70, and 11 age-similar subjects with normal vision, were examined with a battery of cognitive and visual tests, an interactive driving simulator, and an on-road driving test. Data were collected on the frequency of real-world accidents and convictions for traffic violations., Results: There were no significant differences between the two groups on any of the cognitive tests. The age-related macular degeneration group demonstrated poorer performance on the driving simulator, including delayed braking response times to stop signs, slower speeds, and more of both lane boundary crossings and simulator accidents. The age-related macular degeneration group also demonstrated poorer overall on-road test performance, including having significantly more points deducted for driving too slowly and for not maintaining proper lane position. However, these effects on the simulator and the on-road test did not translate into an increased risk of real-world accidents for the age-related macular degeneration group. Significantly more control subjects than patients with age-related macular degeneration were involved in self-reported accidents, and significantly more control subjects had state convictions for traffic violations. There was evidence of compensation in the age-related macular degeneration group in four major areas: (1) not driving in unfamiliar areas; (2) traveling at slow speeds; (3) self-restricting their nighttime driving, and (4) taking fewer risks while driving (eg, not changing lanes). There was also evidence of compensation in the older control group., Conclusions: Vision, simulator, and on-road test variables combined with subjective risk taking predicted self-reported real-world accidents in a logistic regression analysis. However, risk taking, rather than simulator or road-test performance, was the most significant predictor for both patients with age-related macular degeneration and the control group.

The driving performance of 20 subjects with central vision impairment due to either Stargardt disease or cone-rod dystrophy (visual acuity, 20/40 to 20/70) was compared with that of 29 control subjects with normal vision who had similar driving histories. Driving performance was defined by accident involvement based on self-report and state records and by an evaluation of performance on an interactive driving simulator. The proportion of individuals involved in accidents in the central vision loss group was comparable to that of the control group. For 13 of the 20 subjects with central vision loss who did not restrict their driving to daylight hours, there was a greater likelihood of involvement in nighttime accidents than in the control group. Visual function measures and simulator indexes did not predict accident involvement for the central visual loss group, although these subjects showed longer braking response times and a greater number of lane boundary crossings than the control group. These findings are in contrast to our previously published report of subjects with retinitis pigmentosa, who were more likely to have been involved in both daytime and nighttime accidents than a control group and for whom visual field extent was significantly related to accident involvement.