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Eccentric viewing training and its effect on the reading rates of individuals with absolute central scotomas: a meta-analysis.

Structured abstract: Introduction: Eccentric viewing training has been a strategy, used by rehabilitation professionals, to help individuals with central vision loss move their eyes in such a way that they focus the incoming light on parts of the retina located away from the center area that has been damaged and improve visual functioning. A number of studies have shown that this type of training can be associated with improved reading rates. Method: A meta-analysis was conducted on data generated from 17 studies that reported the effect of appropriate magnification and eccentric viewing training on the reading rate of trainees with central scotomas. Results: Almost all eccentric viewing training methodologies were found to be associated with comparable final reading speeds, and no significant differences in final reading speed were found between eccentric viewing training methodologies with comparable age participants. A negative relationship between age and final reading speed was found through correlation analysis, and a correlation was found between visual acuity and the percentage of change in reading speed. Regression models using combinations of age, acuity, and treatment hours were found that could be used to predict the final reading rate using age and number of training hours. Discussion: This analysis provided no statistical basis to determine if one of the treatment protocols described in these studies was more effective in improving the reading rate than another, and there was quite a bit of variability in the protocols described. Implications for practice: Eccentric viewing is an effective way for individuals with central scotomas to improve the use of the vision that they have. Evidence from this meta-analysis suggests that a wide range of training protocols would be effective, and the personal preferences of the instructor and consumer can be given significant consideration during program planning.

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Between 70 to 80% of what people with typical full vision learn comes through information gathered through vision (Li, 2004). The central part of the retina is the area through which information about details in the environment is typically acquired (Riordan-Eva & Whitcher, 2004). These details can be objects in the distance such as signs, people, and obstacles in one's path or objects more proximal such as food on a plate, faces of people in conversation, or information on the printed page. There are a number of diseases, however, that can damage the central part of the retina, leaving the affected person without vision in this area and the ability to discern detail (Bishop, 1996; Riordan-Eva & Whitcher, 2004). Before the 1960s, a popular belief was that individuals with low vision should refrain from using their vision because overuse could result in individuals using up or wearing out their vision. Subsequent research helped people understand that this was not the case (Hatlen, 2000). As a result, practitioners in the field of low vision began to investigate systematic methods to help individuals with low vision to maximize the effectiveness of the vision that they had.

Eccentric viewing is one of the strategies that has been implemented over the years to help individuals who have a loss of central vision (Cheong, Lovie-Kitchen, & Bowers, 2005; Graessley & Kirby, 1996). Eccentric viewing training helps individuals learn to move their eyes in such a way that they focus the incoming light on parts of the retina located away from the central area that has been damaged (Holcomb & Goodrich, 1976).

A number of studies have shown that this type of training can be associated with improved reading rates (Cheong et al., 2005; Crossland, Culham, Kabanarou, & Rubin, 2005; Frenesson, Jakobsson, & Nilsson, 1995; Deruaz et al., 2006). Many of these studies describe intervention protocols that include three basic steps: prescribing appropriate magnification, helping the individual identify effective eccentric viewing locations on their retina, followed by practice and often some type of follow-up support. There were, however, notable differences from study to study in the particulars of each of these steps. Methods used to identify the proper eccentric viewing location, the type of training used after the viewing location has been identified, equipment employed, and the intensity and length of support after the initial training--all varied from study to study. The overall purpose of this meta-analysis was to determine if there were differences in outcomes related to reading rate between studies and the associated particulars of the training methods employed.

Literature review

Loss of vision in the foveal, or central part of the retina, can be a result of a number of pathologies (Bishop, 1996; Riordan-Eva & Whitcher, 2004), the most prevalent pathology being age-related macular degeneration (AMD) (Retina International, 2010). This condition affects 1.75 million people in the United States alone, 1.47% of the population over 40 and 15% of women over 80 (National Eye Institute, 2010). For younger individuals, Stargardt's disease, Best's disease, diabetic retinopothy, and optic nerve atrophy can also result in central scotomas (Nilsson, 1989). Stargardt's disease is hereditary, affects 1 in 8,000 to 10,000 individuals, and often first begins to manifest itself in childhood. The significant impact it has on vision usually does not occur until an individual is in their 40s (Altaweel, 2010). Best's disease, or vitelliform macular dystrophy, is an eye condition that usually begins to appear as a lesion in the macula during childhood (Altaweel, 2010). Diabetic retinopathy is damage to the retina due to diabetes. When these conditions result in the loss of the central field of vision, they can have significant impact on an individual's ability to conduct many common activities such as preparing food, foot travel, driving, recognizing faces, watching TV, and reading (Bullimore, Bailey, & Wacker, 1991; Vukicevic & Fitzmaurice, 2005a; 2005b; 2009). Optic nerve atrophy is caused by damage to the optic nerve (Blind Babies Foundation, 1999).

If the ability to perceive detail through the central field is lost, however, individuals can be trained to use another part of the retina to take over the task of acquiring detailed visual information (Goodrich, 1986). The use of this alternate area of the retina is called eccentric viewing (Holcomb & Goodrich, 1976). Because the density of receptor cells that detect detail decreases farther away from the fovea, eccentric viewing is often combined with magnification and illumination to achieve increased functionality (Fuller & Schmiedecke, 2006; Goodrich, 1986).

Both accuracy of word and letter recognition (Deruaz et al., 2006; Holcomb & Goodrich, 1976; Nilsson & Nilsson, 1986; Nilsson, 1990; Nilsson, Frennesson, & Nilsson, 2003), and reading rate (Cheong et al., 2005; Crossland et al., 2005; Frennesson et al., 1995; Gustafsson & Inde, 2004; Logan, 2005; Palmer, Logan, Dutton, & Nabili, 2009; Nilsson, 1990; Nilsson et al., 2003) have been shown to increase significantly after a program of both eccentric viewing training and optimization of optical devices has been implemented. In addition, other important skills have been restored for people who have had eccentric viewing training, including skills related to employment (Nilsson et al., 2003) and skills related to the activities of daily living such as cooking, traveling on foot, and watching television (Vukicevic & Fitzmaurice, 2005a; 2005b; 2009).

Although training in the area of eccentric viewing is common, widespread, and considered standard practice, a great deal of variation exists in the procedures for evaluation, time spent in training, and the techniques used for both evaluation and training (Stelmack, Massof, & Stelmack, 2004). An important first step in the rehabilitation process to build skill in eccentric viewing is helping the individual identify the most useful part of the retina on which to aim the incoming light and image. Because scotomas have a wide variety of shapes and sizes (Sunness, Applegate, Haselwood, & Rubin, 1996), the selection of the best location may differ greatly from one individual to another. The accurate selection of the most appropriate location may be complicated by the fact that one area of the retina may provide a better image but focusing on the image in that area may be more difficult for the individual to sustain for extended viewing periods (Altpeter, Mackeben, & Trauzettel-Klosinski, 2000).

Often, individuals can identify a preferred retinal location on their own (Cummings, Whittaker, Watson, & Budd, 1985), and results have been mixed from formal studies that have tried to find a single area of the retina that can provide the most functionality for everyone. Fletcher and Schuchard (1997) suggested that individuals prefer not to use areas on the retina above or to the right of the scotoma. In a subsequent study, however, Fletcher, Schuchard, and Watson (1999) found that for participants who had no training, 33% of variance in reading rate was due to scotoma location relative to their chosen preferred reading location, and 42% was due to visual acuity. Watson, Schuchard, De l'Aune, and Watkins (2006) found that individuals who used a preferred retinal location to the left of or above their scotoma had more difficulty navigating through text. Timberlake, Peli, Essock, and Augliere (1987) found increased reading speeds for individuals who focused below left or above fight of the scotoma.

Similarly, Messias et al. (2007) showed that individuals with Stargardt's disease often choose an area below the scotoma. Sunness et al. (1996), however, found that for patients with geographic atrophy, 65% placed

the scotoma to the right of their preferred location, 15% to the left, and 22% above the preferred fixation area. Those with Stargardt's disease tended to place the scotoma far above the fixation site. Reading rates were also found to be faster when the scotoma was above the fixation area and slower when the scotoma was to the left.

Further complicating matters, multiple studies have found evidence that individuals may commonly use multiple locations on the retina at different times when viewing something, and that this skill has been associated with improved perception (Duret, Issenhuth, & Safran, 1999; Deruaz et al., 2004; Messias et al., 2007; Goldschmidt, Deruaz, Lorincz, & Whatham, 2010; Raasch, 2004). In fact, the use of multiple locations has been found to be more likely in individuals who have larger scotomas (Whittaker, 1988). It has been hypothesized that the use of multiple locations may be to compensate for Troxler's phenomenon, or the natural fading of image clarity as viewing time increases (Raasch, 2004; Duret et al., 1999). High resolution is not always required for every task, and patients with Stargardt's disease were found to vary the location they use on the retina depending on the task being performed and the distance from which important information was being viewed (Sullivan, Jovancevic, Hayhoe, & Sterns, 2005). For participants with visual acuities between 20/80 and 20/200, Sunness et al. (1996) also found that their reading rate was not associated with visual acuity in the eccentric viewing area or with the age of the patient, but was associated with the size of the scotoma. Some researchers have studied different training protocols to identify ones that might be most effective. Some differences between techniques were found but participants in these studies were individuals with normal vision where scotomas were simulated (Fornos, Sommerhalder, Rappaz, Pelizzone, & Safran, 2006; Yu, Cheung, Legge, & Chung, 2010; Yu, 2010). Some studies were designed to evaluate the effectiveness of particular eccentric viewing training software such as EccVue software (Fitzmaurice & Clarke, 2000; Vukicevic & Fitzmaurice, 2005a; 2005b) and Movitext (Gustafsson & Inde, 2004). Other studies were designed to evaluate the effectiveness of biofeedback (Vingolo, Salvatore, & Cavarretta, 2009), ocular-motor training (Seiple, Grant, & Szlyk, 2011), sensomotoric training (Nhung, Nguyen, Stockum, Hahn, & Trauzettel-Klosinski, 2011; Seiple, Szlyk, McMahon, Pulido, & Fishman, 2005), and reading practice (Palmer et al., 2009; Seiple et al., 2011). There has been evidence that training to access information that has certain visual characteristics does not necessarily transfer to objects with other illumination characteristics (Chung, Levi, & Li, 2006), so that the transfer of skills learned in one context may not necessarily transfer to another--especially with electronically generated visual targets.

In addition, more extensive training may not necessarily bring additional benefits. A study by Zeevi, Peli, and Stark (1979) suggested that eccentric fixation within the near periphery, plus or minus 8 degrees, can be achieved within a short period of time (10-40 seconds), even in individuals who are new to the task. Furthermore, effects may fade without sustained practice (Deruaz et al., 2006). Yet, as individuals gain experience, their ability to immediately fixate eccentrically improves, as demonstrated by smoother eye movements to achieve effective eye positioning (Zeevi et al., 1979).

The purpose of this study was to conduct a meta-analysis of the data generated and presented from published studies in which researchers have detailed training protocols, and to find if any particular intervention protocol or particular factors, such as participant age and acuity, were associated with significantly different outcomes in terms of reading speed.

Method

DATA COLLECTION

Identification of key words

The initial key words for this project were provided by the American Printing House for the Blind (APH): visual efficiency, visual plasticity, functional visual development, visual skills, visual utilization, Barraga, program to develop functional visual efficiency (PDFVE), Randy Jose, Anne Corn, sensory processing, visual efficiency, low vision, low vision training, low vision skill development, visual perceptual skills, object skills recognition, visual discrimination, visual recognition, visual identification, visual spatial relationship, visual memory, figure ground relationship, visual skills acquisition, visual closure, learning to see and visual training. Additional key words were added as the search progressed and reviewers provided feedback: peripheral vision, eccentric viewing, video training, central scotoma, macular degeneration, AMD, Stargardt's disease, vision rehabilitation, eccentric fixation, and preferred retinal locus (PRL).

Collection of literature

An initial computer-based search using the University of Arizona Central Search through Social Science and Life and Health Sciences data bases was undertaken. Similar, more focused searches using the initial results from the central search were conducted using PubMed, ERIC, and Web of Knowledge, and reviewing articles identified by an "articles cited by" link when available. A similar search was conducted using Google Scholar as well.

Sorting the literature

The abstracts of the articles, obtained through the process outlined above, were reviewed and those articles that related to eccentric viewing training were sorted into a separate list. Copies of relevant articles were obtained and their lists of references reviewed for relevant articles not yet identified. Those articles that were relevant were collected and their lists of references were reviewed for additional articles. The newly identified articles were then obtained and their references were reviewed. This process was repeated until no new and relevant articles were identified.

The collected articles were then more closely reviewed to determine if they had been published and peer reviewed, if the participants in the studies were identified as individuals with visual impairment, and if they reported on research-related interventions associated with improving eccentric viewing skills and reading rate for individuals.

DATA EXTRACTION AND ANALYSIS

Measures

Dependent or outcome variables. Reading rate: All measures for reading rates given in the studies were converted to words per minute. Percent change in reading rate and final reading rate in words per minute were used as outcome variables. Effect sizes were determined by calculating the appropriate Cohen's d for each study. The significance in the differences between pre- and post-treatment results (or control and treatment results) was reported based on information provided in the individual studies. In those cases where significance was not reported, significance was calculated based on data provided in that study, if possible.

Independent variables and factors. The independent variables used in this analysis were overall treatment hours and treatment duration. Age of participants and visual acuity were incorporated as additional factors.

Analysis

Bivariate correlation was used to determine if there were simple correlations among the following variables: final reading rate in words per minute, change in reading speed (percentage and words per minute), effect size (Cohen's d), length of training period, amount of training, average age of participants in each study, and average visual acuity of participants in each study. An independent samples t test was used to determine if there were significant differences between the final reading rates reported in the different studies. Although conducting a one-way analysis of variance, ANOVA and F-test would normally be appropriate for this type of analysis in order to reduce the chance of a false rejection of a true null hypothesis (type 1 error), in this instance only summary data was available. If individual data points were available for each study, an ANOVA could have been run instead of multiple t tests. Regression analysis was conducted to determine if a predictive model could be developed for final reading rate or improvement in reading rate-based number of training hours, with age of participants and visual acuity of participants included as additional factors.

Microsoft Excel software was used to calculate means and standard deviations from data extracted from individual studies (see Table 1) and to calculate values of the t statistic for comparisons between studies (see Table 2). Results for correlations were considered significant at p < 0.05. For the multiple t tests, individual results were considered significant at p < 0.0007 in order to reduce the probability of a false positive to 0.05 using a Bernoulli correction (Glantz, 2002). SPSS software was used to conduct the correlation analysis (Table 3) and regression analysis.

Results

Fifty-three articles were found to be related directly to the development of eccentric viewing skills. Of these, eight were eliminated because they described the biological and optical foundations of eccentric viewing. Eighteen more were eliminated because they did not describe a treatment; six were eliminated because they were articles that did not have individuals with visual impairments as subjects, but simulated visual impairment through some form of occlusion. Of the remaining articles, four were not available in English and nine did not describe outcomes related to reading or included information on reading accuracy and comprehension but not reading rates. After review, the term preferred retinal locus was added to the search, using the same criteria, and additional articles were located. This left sixteen articles that contained information on training protocols and effects on the reading rate of participants. Summaries of these articles and the relevant data they included are contained in Table 1.

Almost all eccentric viewing training methodologies were found to be associated with comparable final reading speeds, but no significant differences in final reading speed were found between eccentric viewing training methodologies with comparably aged participants (see Table 2). There were significant differences, however, between the comparable age groups that were not provided with eccentric viewing training (see Nilsson, 1990) and those that were provided with eccentric viewing training. Studies in which there were younger participants and no training (see Crossland et al., 2005; Crossland, Culham, & Rubin, 2004) achieved results similar to those studies with older participants with training. The study with younger participants and training (Nhung et al., 2011) generally showed the highest final reading speeds. The negative relationship between age and final reading speed was further confirmed through correlation analysis, shown in Table 3. A correlation was also found between visual acuity and the percent change in reading speed.

Regression models were built using different combinations of three independent variables: age, acuity, and treatement hours (for example, age, acuity, and treatment hours; age and treatment hours; acuity and treatment hours; and age and acuity). In these models, age, acuity, and treatment hours were not found to predictive of Cohen's d, or change in reading rate. Using the data from these studies, regression models built using combinations of age, acuity, and treatment hours were not significantly predictive of Cohen's d, or the change in reading rate. The final reading rate, however, could be predicted with age and number of training hours using linear regression (p = 0.002). Number of training hours was positively predictive (beta = 0.386, p = 0.046) and age was negatively predictive (beta = -0.671, p = 0.002). This suggested that the more hours spent in training, the faster the final reading speed would be for trainees; however, the older the trainees were, the lower the final reading rate was.

Discussion

Detailed information on the comparisons and correlations were provided despite the lack of significant differences found, because potential trends could be identified and the lack of significance may have been more a function of the small data set rather than a lack of actual association. Further studies that use greater sample sizes might resolve some of the differences suggested by the comparisons and correlations found here.

This analysis provided no statistical basis to determine if one of the treatment protocols described in these studies was more effective in improving reading rate than another, and there was quite a bit of variability in the protocols described. For example: (1) two studies described an intervention that did not include training (Crossland et al., 2005; Nilsson, 1990), and another had up to nine weeks of training (Gustafsson & Inde, 2004); (2) one intervention involved simply describing what eccentric viewing was to the participants (Crossland et al., 2005), and others followed up with training some with formal practice (Frennesson et al., 1995; Nilsson, 1990; Nilsson et al., 2003; Palmer et al., 2009); or training with self-guided practice (Cheong et al., 2005); (3) still other studies described using high technology training systems with computer software (Gustafsson & Inde, 2004) and displays (Nilsson et al., 1998), and (4) finally, another had intensive initial instruction with subsequent coaching by a vision specialist (Frennesson et al., 1995). In addition, other groups of researchers employed biofeedback (Vingolo et al., 2009) or sensomotoric training (Nhung et al., 2011). The fact that no difference was found between any of the protocols except in one case (Nilsson, 1990) where there was no treatment may suggest a certain flexibility in the learning process or alternately an upper limit on reading speed using eccentric viewing. Indeed, Crossland et al. (2005) described a minimal intervention and the results were not significantly different from the intervention studies but were significantly different from the nonintervention group in Nilsson (1990).

Although many of the correlations were not found to be significant, the strength of the correlations is suggestive and offers guidance for further investigation. For example, final reading rate may be negatively correlated with age. Because the participants in these studies tended to be older, there may be an upper limit on reading speed related to age. In fact, Crossland et al. (2004; 2005) showed that younger participants adapted to and learned eccentric viewing techniques more quickly than older participants did.

Data on the effect of training on final reading rate was mixed. In the regression model, more training was predictive of higher final reading rate and yet the correlation was not strong in the bivariate correlation analysis. The regression analysis accounted for the confounding factor of age and may strengthen the case for longer training periods. At the same time, Gustafsson and Inde's (2004) findings suggested that individuals may be able to identify an effective eccentric viewing location without assistance and then selftrain. Additionally, individuals tended to adjust and change their preferred viewing location spontaneously (Duret et al., 1999; Deruaz et al., 2004; Messias et al., 2007; Goldschmidt et al., 2010; Raasch, 2004). It may be that interventions in which methods are prescribed by a trainer are interfering with the natural monitoring and adjusting process of the trainees. Training that is less prescriptive and more collaborative might be more effective.

Further research could be conducted that establishes the relative importance of various components of eccentric viewing intervention on reading outcomes. For example, understanding the relative importance of magnification, identification of a preferred viewing locus, and training could help guide intervention protocols. Because outcomes between the various treatment protocols were not significantly different, evidence from this analysis may suggest that perhaps prescribing proper magnification is associated with the most significant contribution to improved outcomes.

The implications for practice are simply that eccentric viewing is an effective way for individuals with central scotomas to improve the use of the vision that they have. Because there did not appear to be one process for training that was associated with higher final reading rates, there is evidence that a wide range of training protocols would be effective, and that the personal preferences of the instructor and consumer should be given significant consideration during program planning.

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Watson, G. R., Schuchard, R. A., De l'Aune, W. R., & Watkins, E. (2006). Effects of preferred retinal locus placement on text navigation and development of advantageous trained retinal locus. Journal of Rehabilitation Research & Development, 43, 761-770.

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Yu, D., Cheung, S., Legge, G., & Chung, S. (2010). Reading speed in the peripheral visual field of older adults: Does it benefit from perceptual learning? Vision Research, 50, 860-869.

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Jon Howe, M.A., doctoral candidate, Department of Disability and Psychoeducational Studies, College of Education. University of Arizona, 1430 East Second Street, P.O. Box 210069, Tucson, AZ 85721; e-mail: <jshowe@email.arizona.edu>.
Table 1
Summary of Studies Used in Meta-Analysis.

                                                      Acuity
                                                       mean
Study         #      Age mean (std)      Condition    logMAR

Cheong et     25          80.3              AMD        .628#
al.,
2005

Crossland     25           16             Various    Not given
et al.,                                     ACS
2005

Crossland,    18        Not given           AMD      Not given
et al.,                                     JMD
2004

Frennesson    10   80.1 (+/-5.6 years)      AMD        1.46#
et al.,                                     ACS
1995

Gustafsson     9          45.8              ACS      1.1-1.54#
& Inde,
2004

Logan,        20           70               ACS      Not given
2005

Nilsson et    18          77.4              AMD       1.398#
al., 2003

Nilsson et     6           71               AMD        1.22#
al., 1998

Nilsson,      20          76.8              AMD        1.1#
1990

Nilsson,      20          77.0              AMD        1.1#
1990

Nilsson R    120        72 (9.9)            SMD        .957#
Nilsson,                                    DMD
1986                                        HMD

Seiple et     16           77               AMD         .75
al., 2005

Nhung et      20           30            Juv. Mac       1.0
al., 2011                                  dystr

              16           31                          1.0#

Palmer et    242          75.4              AMD      Not given
al., 2009

Seiple et     30           79               AMD        .823#
al., 2011

              30           79               AMD        .823#

              30           79               AMD        .823#

               6          78.4              AMD        .900

Vingolo et     5          53.8            Var. w       .546
al., 2009                                   ACS

Watson et      7          75.7                         .91
al., 2006

                                                     Length of
Study           Intervention          Design          interv

Cheong et    In office prac In    Pre/post With    In office
al.,         office+              Control          2 week
2005         at home In                            training
             office +
             home+
             frame

Crossland    None                 Pre/post         < 1yr
et al.,      Self-discovery
2005         of PRL and
             Monitor

Crossland,   No training          Pre/post         12 mo.
et al.,
2004

Frennesson   1/2 hr on training   Pre/post         Not given
et al.,      program and
1995         1 hr. work
             with vision
             spec.

Gustafsson   MoviText             Pre/post         6 to 9
& Inde,      method                                weeks
2004         3--1hr
             sessions

Logan,       Determination        Pre/post         Ave 6.5
2005         of PRL               Mixed            hrs
             Optimal              method
             refraction
             Train (6.5 hr
             sessions)
             Independent
             practice

Nilsson et   Determination        Pre/post         Not given
al., 2003    of PRL
             Refraction
             Train (5.2 hr
             sessions)
             Independent
             practice

Nilsson et   Computer video       Pre/post         4 weeks
al., 1998    display
             training in
             TRL

Nilsson,     Optical Aids         Pre/post         4 weeks
1990         Instruction in                        approx
             use of aids
             Eccentric
             viewing
             training

Nilsson,     Optical Aids         Pre/post
1990         Instruction in
             use of aids

Nilsson R    Weekly               Pre/post         variable
Nilsson,     rehabilitation
1986         sessions as
             needed

Seiple et    Eye-movement         Pre/post         8 weeks
al., 2005    training

Nhung et     Rapid serial         Pre/post         4 weeks
al., 2011    visual
             presentation
             sensomotoric
             training             Pre/post         4 weeks

Palmer et    Determination        Pre/Post Retro   Retrospective
al., 2009    of PRL               Analysis
             Optimal              Paired t
             refraction
             Optimal
             lighting Train
             (3-4 1hr
             sessions)
             Supervised
             practice

Seiple et    Visual               Random           6 weeks
al., 2011    awareness            repeat,
             and eccentric        measure,
             viewing              counter
                                  balance,
                                  crossover

             Reading eye                           6 weeks
             movement

             Reading                               6 weeks
             practice

             Control (no                           18 weeks
             training)

Vingolo et   MP-1                 Pre/post         10 weeks
al., 2009    Biofeedback
             examination

Watson et    Trained to use       Pre/post         n/a
al., 2006    reinal locus
             below
             scotoma

             Ave # of 1 hr.     WPM B: Before          %
Study           sessions           A: After         change

Cheong et      Not given      B: 66.00 (12.16)       19.2%
al.,                          A: 78.67
2005                          (10.263)#

Crossland          5          B: 58(33)             53.4%#
et al.,                       A: 89 (35)
2005

Crossland,        n/a         B: 85 (37) A:73        -14.1
et al.,                       (38)
2004

Frennesson   2.6 (+/-0.69)    B: 11.5 (4.5)          412%#
et al.,                       A: 58.9 (19.7)
1995

Gustafsson         3          B: 45.4 (37.87)        57.2%
& Inde,                       A: 80.4 (41.65)#
2004

Logan,             5          B: 44.1 A: 68.7       24.6%#
2005

Nilsson et        5.2         B: 9.0 (5.8)           659%
al., 2003                     A: 68.3 (19.4)

Nilsson et   4 Inns median    B: 0 -12                --
al., 1998                     A: (71) 62-76

Nilsson,        4.8(1.0)      B: 0                    n/a
1990                          A: 75.5 (31.1)

Nilsson,           0          B: 0                    n/a
1990                          A: 22.6 (22.2)

Nilsson R     Not reported    B: 0                    n/a
Nilsson,                      A: 84.3 (43.9)
1986

Seiple et     Not reported    B: 91                  27.1%
al., 2005                     A: 115.7

Nhung et       20 1/2 hr      B: 83 (23)             25.3%
al., 2011                     A: 104 (31.9)

                              B: 102 (46.7)#
               20 1/2 hr      A: 122 (25.9)#         19.6%

Palmer et      3.8 (1.6)      B: 48 (35) A: 71.9    49.8%#
al., 2009                     (30.5)

Seiple et        2hr/wk       B: 64.8 (36.5) A:      -13%
al., 2011                     56.4

                 2hr/wk       B: 64.8 (36.5)         42.1%
                              A: 92.1#

                 2hr/wk       B: 64.8 (36.5)         -15%
                              A: 55.2#

                  n/a         Not given            Not given

Vingolo et     20 min/wk      B: 64.3 (68)           42.7%
al., 2009                     A: 91.8 (86.3)

Watson et     15 im total     B: 7.4 A: 34.1        -54.1%
al., 2006

                          Significance
                WPM          (Stat.      Effect size(r)
Study          change       method)        (Cohen's d)

Cheong et      12.67      Pre/post       0.9208 (4.722)
al.,                      P=0.02
2005                      (unpaired)

Crossland        31       <0.05          0.4146 (0.9114)
et al.,                   (ANOVA)
2005

Crossland,      -12       Not reported   -.1580 (-.3200)
et al.,
2004

Frennesson      47.4      <0.001 (not
et al.,                   given)
1995

Gustafsson       35       <0.005         0.7181 (2.0635)
& Inde,                   (Paired t)
2004

Logan,          24.6      Not given      Insufficient
2005                                     information

Nilsson et      59.3      <0.001 (not    0.9005 (4.1417)
al., 2003                 given)

Nilsson et     Insuff     na             Insufficient
al., 1998      inform                    information

Nilsson,        75.5      < 0.001        Insufficient
1990                                     information

Nilsson,        22.6      Insufficient   Insufficient
1990                      information    information

Nilsson R       84.3      Not reported   Insufficient
Nilsson,                                 information
1986

Seiple et       24.7      p = 0.001      Insufficient
al., 2005                 Wilcoxon       information
                          rank sum
Nhung et         21       p = 0.01       .3532 (.7551)
al., 2011                 (paired-t)

                          p = 0.006
                 20       (paired-t)     .2560 (.5297)

Palmer et       23.9      < 0.001 (not   0.3421 (0.7281)
al., 2009                 given)

Seiple et    -8.4 (7.2)   Ns             Insufficient
al., 2011                                information

             27.3 (6.8)   p = 0.0002     Insufficient
                          (t test)       information

             -9.6 (7.2)   Ns             Insufficient
                                         information

             .96 (1.3)    ns             Insufficient
                                         information

Vingolo et      27.5      P = 0.04       .1743 (.3540)
al., 2009                 (paired-t)

Watson et      -40.3      Not reported   Insufficient
al., 2006                                information

Note: ACS = absolute central scotoma, PRL = Preferred reading
location, AMD = Adult macular degeneration, DR = Diabetic
retinopothy, Gl Glau coma, OA = Optic Atrophy, M = Myopia, EVT =
eccentric viewing training. JMD = Junior Macular Degeneration.

Italicized numbers calculated for this study from data provided
in articles.

Effect size calculator: http://www.uccs.edu/~faculty/lbecker/

Cohen's d (Gravetter & Wallnau 2005.).

Cohen's d for t/test repeated measures (non/paired) = (mean
difference/std deviation) and effect size r=[[([t.sup.2]/
([t.sup.2]+df)].sup.1/2].

Small effect: 0 < d < 0.2, medium effect 0.2 < d < 0.8, large
effect 0.8 < d < 1.0.

Note: Numbers calculated for this study from data provided
in articles were indicated with #.

Table 2
Comparison of final reading rate between studies.

                  Cheong    Crossland   Crossland
                  et al.     et al.      et al.      Frennesson
                  (2005)     (2005)      (2004)     et al. (1995)

Cheong et al.
(2005)              --

Crossland
(2005)           -0.5010
Crossland
et al. (2004)     0.2519     1.4269

Frennesson
et al. (1995)     1.6368     2.5481      1.0886

Gustafsson &
Inde (2004)      -0.0707     0.5988     -0.4648       -1.4666

Palmer et al.
(2009)            0.3819     2.6313      0.1450       -1.3349

Nilsson et al.
(2003)            0.8916     2.2662      0.4674       -1.2219

Nilsson (1990)    0.2421     1.4318     -0.1037       -1.4010

Nilsson (1990)    4.2289`    7.0764 *    4.8587 *      4.3073 *

Nilsson et al.
(1998)           -0.2211     0.5026     -1.0347       -1.8094

Nhung et al.
(2011)           -1.3410    -1.4852     -2.7329       -4.0783

Nhung et al.
(2011)           -2.8016    -3.2404     -4.3364 *     -6.5866 *

Vingalo et al.
(2009)           -0.2543    -0.1243     -0.7311     -1.1871

                                  Palmer
                  Gustafsson      et al.     Nilsson et    Nilsson
                 et al. (2004)    (2009)     al. (2003)    (1990)

Cheong et al.
(2005)

Crossland
(2005)
Crossland
et al. (2004)

Frennesson
et al. (1995)

Gustafsson &
Inde (2004)

Palmer et al.
(2009)              0.5641

Nilsson et al.
(2003)              0.7989        0.4929

Nilsson (1990)      0.3358       -0.3083     -0.6829

Nilsson (1990)      3.6330 *      6.7211 *    6.5765 *     8.0861 *

Nilsson et al.
(1998)             -0.1788       -3.1291     -1.5204      -2.5975

Nhung et al.
(2011)             -1.2698       -4.5081 *   -4.1099 *    -4.2231 *

Nhung et al.
(2011)             -2.3888       -6.4161 *   -6.8911 *    -6.6342 *

Vingalo et al.
(2009)             -0.2937       -1.3680     -1.1198      -0.8387

                              Nilsson                Nhung
                  Nilsson     et al.     Nhung et    et al.
                   (1990)     (1998)    al. (2011)   (2011)

Cheong et al.
(2005)

Crossland
(2005)
Crossland
et al. (2004)

Frennesson
et al. (1995)

Gustafsson &
Inde (2004)

Palmer et al.
(2009)

Nilsson et al.
(2003)

Nilsson (1990)

Nilsson (1990)

Nilsson et al.
(1998)            -5.8387

Nhung et al.
(2011)            -9.0301 *   -1.9215

Nhung et al.
(2011)           -12.0513 *   -3.3513   -1.8251

Vingalo et al.
(2009)            -3.2108     -0.3580    0.5280      1.2870

Significant p < 0.0007.

Note: Only studies that provided standard deviations for their
reported final reading rate were included in this analysis.

Table 3
Bivariate Pearson correlations between variables.

                   Age      Acuity    WPM change   Cohen's d

Acuity            .073
WPM change       -.015      .422
Cohen's d         .671      .216        .474
Sessions         -.215     -.252        .003         -.229
WPM final        -.573 *   -.279        .274         -.392
Percent change    .221      .808 **     .688 **       .563

                 Sessions   WPM final

Acuity
WPM change
Cohen's d
Sessions
WPM final          .479
Percent change    -.229       -.140

* Significant p < 0.05.

** Significant p < .001.
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Title Annotation:CEU Article
Author:Howe, Jon
Publication:Journal of Visual Impairment & Blindness
Article Type:Clinical report
Geographic Code:1USA
Date:Sep 1, 2012
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