**8. Updated reading skills development strategies**

### **8.1 Introduction**

Reading is one of the most important visual activities, requiring complex cognitive processes. One of the most important reading skills is reading speed, being critical to understand the reading text. But achieving an adequate reading speed for compression requires mastery of the various eye skills and movements described above. The stimulus required for an optimal reading is also important. Its parameters are: characters size subtending 0.3–2°; field size up to 4 characters independent of character size; bandwidth up to 2 cycles/degree independent of character size; and 1 spatial-frequency channel suffices for reading [3]. Visual spam requires 7–11 characters to be recognized at the fovea for normal reading rates during fixation [56]. It is well-known that the maximum visual acuity is located in the fovea and decreases directly with eccentricity [57].

In a meta-analytic study, reading skills components were evaluated to determine their importance on reading comprehension in healthy adults. Results showed a great relationship between comprehension and the following skills: morphological awareness, language comprehension, fluency, oral vocabulary knowledge, real word decoding and working memory [58].

This section will address the assessment of cognitive skills in a rehabilitation program, the eccentric viewing training, the optical correction and other training techniques such as oculomotor control and perceptual training.

#### **8.2 Cognitive skills**

Assessment of cognitive skills is the step prior to the development of a visual rehabilitation program. Several tests are used for cognitive skills evaluation, such as MoCA, MMCT or CDT [59] or the scale COGEVIS, which is specially designed for low vision patients [60]. Also, it is essential to evaluate the level of literacy of the patient before visual and reading evaluation. If the patient is illiterate or has a low level of reading comprehension, it may be useful the tumbling E test for visual acuity [3].

#### **8.3 Eccentric viewing training and preferred retinal loci (PRL)**

Eccentric viewing consists of using a non-central part of the retina for viewing. In this method of vision, given when central retina is damaged, the eye uses an eccentric retinal location, known as preferred retinal loci (PRL) [61]. It is common for many patients with eccentric viewing not to realize that they are fixing in that way. According to Jeong and Moon, no improvements were found in best corrected visual acuity after 2 weeks of self-training; however, there were significant improvements in reading speed and satisfaction scores [61].

Nowadays, microperimeters can evaluate the visual field and the PRL even in patients without fixation, correlating the exact retinal locations with the visual field [62]. There are two microperimetry techniques: static and dynamic. The first of these can detect mild scotomas and defining their shape, with no movement of the stimulus. In dynamic microperimetry, the stimulus moves from the periphery towards the point of fixation, presenting difficulties in identifying the relative scotomas [7].

Sometimes PRL is not located in an appropriate area and it should be relocated in a better retinal location, closer to the fovea so visual acuity will be the best [7]. Some studies have shown that patients trend to develop the PRL at the left side of the atrophy [63]. However, Greenstein et al. evaluated several patients with

**89**

yellow filter [71].

smaller print [72].

*Training Reading Skills in Central Field Loss Patients: Impact of Clinical Advances…*

macular disease such as AMD and Stargardt disease, founding a majority of PRL located above the atrophic lesion [64]. A superior or inferior location of the PRL is better than a left location for reading because scotoma does not interfere much in

In some patients, oculomotor deficits can reduce reading skills, so training methods with using eye movements are needed for these patients. It is the case of Rapid Serial Visual Presentation (RSVP) training, which allows PRL training without eye movements to read. The words of the sentence are presented one by one at the center of the screen, allowing reading without eye movements because fixation

Optical correction plays a very important role to make the most of patients' vision. Nevertheless, optical correction is not only optical lenses with the correction of patients' refractive error, but also adds power for reading distance and prisms if

As a field defect, prisms can be used for AMD patients. Several studies have been conducted to determine the benefits of repositioning the retinal image in its PRL, the area of the retina where the subject looks and replaces the pitting, using prisms in patients with macular degeneration. Three different studies evaluated the use of prisms in subjects with AMD, shifting the image from the visual field to the PRL predetermined by the subject for rehabilitation [66–68]. Visual acuity was assessed with the best correction, obtaining significant values of improvement with the use of prisms. In addition, the PRL preferred by patients was mostly in the upper retina and showed conformity and adaptation to the use of prisms in the three studies. This indicates that the use of prisms, with good PRL delimitation, may be an

First of all, we must make a distinction between optical devices and non-optical

Contrast plays an important role on training reading skills. Reading materials should have a 100% black and white contrast and reading conditions should reduce the amount of glare, specially created by short wavelength light. Also, light position is a crucial point to be considered, being recommendable that light source is placed above or behind the patient [3]. Finally, text font is also important. In a Canadian research with patients with AMD, Courier text font was found as the most recommendable font for these patients, whereas Arial was found as the worst for reading

devices for low vision patients. An optical aid is an optical system made up of high-powered lenses that help people with reduced vision make the most of their remaining vision. On his behalf, a non-optical aid, such as light flexes or lecterns, is a complement to help make the most of vision.  Filters are used in patients suffering from photophobia and glare and they have a great visual impact in macular disease patients [7]. Over the years several studies have shown the effects of filters on glare, but there is no global filter prescribing protocol for each disease [69–71]. One of those studies found that with a blue-violet filter, patients with central and peripheral scotoma improved visual acuity, contrast sensibility and glare better than the

*DOI: http://dx.doi.org/10.5772/intechopen.88943*

with the PRL is maintained on the screen [3].

**8.4 Optical correction and the use of prisms**

appropriate rehabilitation option for patients with AMD.

**8.5 Training materials and devices**

continuous reading.

necessary [65].

*Training Reading Skills in Central Field Loss Patients: Impact of Clinical Advances… DOI: http://dx.doi.org/10.5772/intechopen.88943*

macular disease such as AMD and Stargardt disease, founding a majority of PRL located above the atrophic lesion [64]. A superior or inferior location of the PRL is better than a left location for reading because scotoma does not interfere much in continuous reading.

In some patients, oculomotor deficits can reduce reading skills, so training methods with using eye movements are needed for these patients. It is the case of Rapid Serial Visual Presentation (RSVP) training, which allows PRL training without eye movements to read. The words of the sentence are presented one by one at the center of the screen, allowing reading without eye movements because fixation with the PRL is maintained on the screen [3].

#### **8.4 Optical correction and the use of prisms**

*Visual Impairment and Blindness - What We Know and What We Have to Know*

Reading is one of the most important visual activities, requiring complex cognitive processes. One of the most important reading skills is reading speed, being critical to understand the reading text. But achieving an adequate reading speed for compression requires mastery of the various eye skills and movements described above. The stimulus required for an optimal reading is also important. Its parameters are: characters size subtending 0.3–2°; field size up to 4 characters independent of character size; bandwidth up to 2 cycles/degree independent of character size; and 1 spatial-frequency channel suffices for reading [3]. Visual spam requires 7–11 characters to be recognized at the fovea for normal reading rates during fixation [56]. It is well-known that the maximum visual acuity is located in the fovea and

In a meta-analytic study, reading skills components were evaluated to determine their importance on reading comprehension in healthy adults. Results showed a great relationship between comprehension and the following skills: morphological awareness, language comprehension, fluency, oral vocabulary knowledge, real word

This section will address the assessment of cognitive skills in a rehabilitation program, the eccentric viewing training, the optical correction and other training

Assessment of cognitive skills is the step prior to the development of a visual rehabilitation program. Several tests are used for cognitive skills evaluation, such as MoCA, MMCT or CDT [59] or the scale COGEVIS, which is specially designed for low vision patients [60]. Also, it is essential to evaluate the level of literacy of the patient before visual and reading evaluation. If the patient is illiterate or has a low level of reading

Eccentric viewing consists of using a non-central part of the retina for viewing.

Nowadays, microperimeters can evaluate the visual field and the PRL even in patients without fixation, correlating the exact retinal locations with the visual field [62]. There are two microperimetry techniques: static and dynamic. The first of these can detect mild scotomas and defining their shape, with no movement of the stimulus. In dynamic microperimetry, the stimulus moves from the periphery towards the point of fixation, presenting difficulties in identifying the relative

Sometimes PRL is not located in an appropriate area and it should be relocated in a better retinal location, closer to the fovea so visual acuity will be the best [7]. Some studies have shown that patients trend to develop the PRL at the left side of the atrophy [63]. However, Greenstein et al. evaluated several patients with

In this method of vision, given when central retina is damaged, the eye uses an eccentric retinal location, known as preferred retinal loci (PRL) [61]. It is common for many patients with eccentric viewing not to realize that they are fixing in that way. According to Jeong and Moon, no improvements were found in best corrected visual acuity after 2 weeks of self-training; however, there were significant

techniques such as oculomotor control and perceptual training.

comprehension, it may be useful the tumbling E test for visual acuity [3].

**8.3 Eccentric viewing training and preferred retinal loci (PRL)**

improvements in reading speed and satisfaction scores [61].

**8. Updated reading skills development strategies**

decreases directly with eccentricity [57].

decoding and working memory [58].

**8.2 Cognitive skills**

**8.1 Introduction**

**88**

scotomas [7].

Optical correction plays a very important role to make the most of patients' vision. Nevertheless, optical correction is not only optical lenses with the correction of patients' refractive error, but also adds power for reading distance and prisms if necessary [65].

As a field defect, prisms can be used for AMD patients. Several studies have been conducted to determine the benefits of repositioning the retinal image in its PRL, the area of the retina where the subject looks and replaces the pitting, using prisms in patients with macular degeneration. Three different studies evaluated the use of prisms in subjects with AMD, shifting the image from the visual field to the PRL predetermined by the subject for rehabilitation [66–68]. Visual acuity was assessed with the best correction, obtaining significant values of improvement with the use of prisms. In addition, the PRL preferred by patients was mostly in the upper retina and showed conformity and adaptation to the use of prisms in the three studies. This indicates that the use of prisms, with good PRL delimitation, may be an appropriate rehabilitation option for patients with AMD.

#### **8.5 Training materials and devices**

First of all, we must make a distinction between optical devices and non-optical devices for low vision patients. An optical aid is an optical system made up of high-powered lenses that help people with reduced vision make the most of their remaining vision. On his behalf, a non-optical aid, such as light flexes or lecterns, is a complement to help make the most of vision.  Filters are used in patients suffering from photophobia and glare and they have a great visual impact in macular disease patients [7]. Over the years several studies have shown the effects of filters on glare, but there is no global filter prescribing protocol for each disease [69–71]. One of those studies found that with a blue-violet filter, patients with central and peripheral scotoma improved visual acuity, contrast sensibility and glare better than the yellow filter [71].

Contrast plays an important role on training reading skills. Reading materials should have a 100% black and white contrast and reading conditions should reduce the amount of glare, specially created by short wavelength light. Also, light position is a crucial point to be considered, being recommendable that light source is placed above or behind the patient [3]. Finally, text font is also important. In a Canadian research with patients with AMD, Courier text font was found as the most recommendable font for these patients, whereas Arial was found as the worst for reading smaller print [72].

#### **8.6 Oculomotor control training**

It is necessary to train eye movements, saccades and fixation stability in order to rehabilitate reading performance. The flashlight technique is useful to train oculomotor movements and fixation stability on distance targets. The patient holds a flashlight and, keeping their head still, follows the light with their eyes. A test variation uses a laser pointer directed to the wall as a stimulus, which allows the patient to detect relative scotomas [3]. The King-Devick test (KDT) for low vision patients is an advanced training of fixation stability, saccades and tracking eye movements. It is based on performance of rapid number naming. In a 6 weeks research with KDT training in first and second grade children, the treatment group improved significantly compared with the control group in reading fluency and reading comprehension, with efficient eye movements [73].

#### **8.7 Perceptual training**

Perceptual training is the last step of the rehabilitation program. Then, an example of a protocol is shown [3]:

#### **9. Assessment and individual reading rehabilitation plan**

Visual impaired patients require an individualize assessment and rehabilitation plan due to the affectation by their pathology varies from one patient to another. This fact makes it difficult to develop a standardized attentional plan for these patients. However, several assessment guidelines for central vision loss patients can be recommended.

Firstly, fluent reading requires a minimal visual acuity of 20/50, a visual field at least of 2° to the right and the left and a holding position of 250 ms between saccades [74].

Nowadays, microperimetry is one of the most important tests in patients with central vision loss. The origin of microperimetry is due to the need to evaluate the visual field in people with unstable or extrafoveal fixation problems or because of problems in the macula. Conventional perimetry is based on the fixation of the subject. If the fixation is extrafoveal and/or unstable, the visual field will not be correct, with values displaced from their true location and incorrect scotoma sizes [75]. Microperimetry allows the points of the visual field to be correlated with the exact retinal location; at the same time, the fundus of the eye can be visualized while visual stimuli are projected [62] (**Figure 3**). It allows also eccentric fixation training.

**91**

*Training Reading Skills in Central Field Loss Patients: Impact of Clinical Advances…*

In macular abnormalities, microsacadic movements are greater than in a normal

*Microperimetric image in which the evaluated points and the anatomical situation in the fundus of the eye are observed (from https://www.canadianjournalofophthalmology.ca/article/S0008-4182(13)00209-3/fulltext).*

An important consequence of central vision loss in some patients is depression, which has a prevalence of 2–5% [78]. Low-vision rehabilitation aids have shown to improve reading speed but no effects on depression have been reported in AMD patients [79]. If traditional rehabilitation protocols do not show a great impact on depression, prevention of depression may be an appropriate action. The sum of visual rehabilitator, behavioral activation and occupational therapist has shown an

An improvement on quality of life and reading has been seen in AMD patients who already use magnifying aids, after a computer-based reading training at home [78]. On that randomized and controlled trial, patients were divided into two groups: primary reading training group and control group with placebo training. Control group started with reading training after 6 weeks of placebo, which consist of crossword puzzles. Reading speed was measured with the German version of the International Reading Speed Texts (IReST), eye movements were measured with a scanning lases ophthalmoscope (SLO); and degree of depression, cognition and quality of life were measured with Montgomery-Asberg Depression Rating Scale (MADRS), dementia detection test (DemTect) and Impact of Vision Impairment (IVI) questionnaires, respectively. Reading speed improved in training group, as well as emotional status. Such results were not given in the control group [78].

**10. Innovative reading rehabilitation strategies and devices: assistive**

With the development of technology, a new field of rehabilitation opened up, beginning with the first electronic aids. Tablets and iPads are currently widely used, even in elderly AMD patients. It has been shown in these patients that they read faster on iPad with larger text sizes when compared with paper. Also, patients reported to have the best clarity with it [80]. Moreover, it has been proved to improve reading speed in low vision patients, as well as other low vision devices

eye, affecting fixation stability [76]. Due to poor fixation stability, the reading speed is affected and reduced [77]. This fixation stability can be improved by train-

ing, and microperimetry is essential for such training.

effective effect on depression.

**Figure 3.**

**devices and technology**

*DOI: http://dx.doi.org/10.5772/intechopen.88943*

*Training Reading Skills in Central Field Loss Patients: Impact of Clinical Advances… DOI: http://dx.doi.org/10.5772/intechopen.88943*

#### **Figure 3.**

*Visual Impairment and Blindness - What We Know and What We Have to Know*

reading comprehension, with efficient eye movements [73].

It is necessary to train eye movements, saccades and fixation stability in order to rehabilitate reading performance. The flashlight technique is useful to train oculomotor movements and fixation stability on distance targets. The patient holds a flashlight and, keeping their head still, follows the light with their eyes. A test variation uses a laser pointer directed to the wall as a stimulus, which allows the patient to detect relative scotomas [3]. The King-Devick test (KDT) for low vision patients is an advanced training of fixation stability, saccades and tracking eye movements. It is based on performance of rapid number naming. In a 6 weeks research with KDT training in first and second grade children, the treatment group improved significantly compared with the control group in reading fluency and

Perceptual training is the last step of the rehabilitation program. Then, an

ideally size is comparable with a newspaper print (size 1 M).

prehensive rehabilitation can be achieved.

• Transfer acquired reading skills into daily life activities.

**9. Assessment and individual reading rehabilitation plan**

• Start with large print: it is important to start with large print and, to decrease the size as the patient improves his or her reading skills. If it is possible, the

• Start reading single letters: its aim is to get the patient to recognize each letter and number detail with eccentric vision for, then, explore simple words. At the end of this process, the patient may be capable of reading a continuous text.

• Use training to improve comprehension: this can be possible by providing the patient reading material with higher levels. Improving reading speed a com-

Visual impaired patients require an individualize assessment and rehabilitation plan due to the affectation by their pathology varies from one patient to another. This fact makes it difficult to develop a standardized attentional plan for these patients. However, several assessment guidelines for central vision loss patients can

Firstly, fluent reading requires a minimal visual acuity of 20/50, a visual field at least of 2° to the right and the left and a holding position of 250 ms between sac-

Nowadays, microperimetry is one of the most important tests in patients with central vision loss. The origin of microperimetry is due to the need to evaluate the visual field in people with unstable or extrafoveal fixation problems or because of problems in the macula. Conventional perimetry is based on the fixation of the subject. If the fixation is extrafoveal and/or unstable, the visual field will not be correct, with values displaced from their true location and incorrect scotoma sizes [75]. Microperimetry allows the points of the visual field to be correlated with the exact retinal location; at the same time, the fundus of the eye can be visualized while visual stimuli are projected [62] (**Figure 3**). It allows also eccentric fixation training.

**8.6 Oculomotor control training**

**8.7 Perceptual training**

example of a protocol is shown [3]:

**90**

be recommended.

cades [74].

*Microperimetric image in which the evaluated points and the anatomical situation in the fundus of the eye are observed (from https://www.canadianjournalofophthalmology.ca/article/S0008-4182(13)00209-3/fulltext).*

In macular abnormalities, microsacadic movements are greater than in a normal eye, affecting fixation stability [76]. Due to poor fixation stability, the reading speed is affected and reduced [77]. This fixation stability can be improved by training, and microperimetry is essential for such training.

An important consequence of central vision loss in some patients is depression, which has a prevalence of 2–5% [78]. Low-vision rehabilitation aids have shown to improve reading speed but no effects on depression have been reported in AMD patients [79]. If traditional rehabilitation protocols do not show a great impact on depression, prevention of depression may be an appropriate action. The sum of visual rehabilitator, behavioral activation and occupational therapist has shown an effective effect on depression.

An improvement on quality of life and reading has been seen in AMD patients who already use magnifying aids, after a computer-based reading training at home [78]. On that randomized and controlled trial, patients were divided into two groups: primary reading training group and control group with placebo training. Control group started with reading training after 6 weeks of placebo, which consist of crossword puzzles. Reading speed was measured with the German version of the International Reading Speed Texts (IReST), eye movements were measured with a scanning lases ophthalmoscope (SLO); and degree of depression, cognition and quality of life were measured with Montgomery-Asberg Depression Rating Scale (MADRS), dementia detection test (DemTect) and Impact of Vision Impairment (IVI) questionnaires, respectively. Reading speed improved in training group, as well as emotional status. Such results were not given in the control group [78].

## **10. Innovative reading rehabilitation strategies and devices: assistive devices and technology**

With the development of technology, a new field of rehabilitation opened up, beginning with the first electronic aids. Tablets and iPads are currently widely used, even in elderly AMD patients. It has been shown in these patients that they read faster on iPad with larger text sizes when compared with paper. Also, patients reported to have the best clarity with it [80]. Moreover, it has been proved to improve reading speed in low vision patients, as well as other low vision devices

such as closed-circuit television (CCTV); being the previous experience with an iPad decisive in order to obtain greater reading speeds [81].

### **10.1 Head-mounted display**

Another technological aids can be a virtual bioptic telescope and a virtual projection screen, implemented in a head-mounted display (HMD) [82]. In this research, two new magnification strategies were developed: a virtual bioptic telescope and a projection screen presented in virtual reality. The first one consists of a user-defined region of a wide-field binocular head-mounted display where the image can be magnified (**Figure 4**). With this system, visual function was significantly improved, including reading. The minimum clinically important difference (MCID) frequency in reading task was 85.7% of participants [82], which shows an appropriated visual aid for central vision loss patients.

## **10.2 Intra-ocular telescopic implants**

Intra-ocular telescopic implants are commercially invasive aids for low vision patients. Dunbar and Shawahir-Scala review showed the different implants available on the market for patients with AMD [83]. These implants consist of intra-ocular lens combined in order to create an optic system. Lipshitz mirror implant (LMI) is a modified conventional intra-ocular lens (IOL) with two miniature mirrors in a combination that creates a dual optical system in a similar way to multifocal IOL. The central part of the IOL magnifies the image while the peripheral portion remains unmagnified. Quality of life improved and single letter near acuity with early treatment diabetic retinopathy study (ETDRS) near vision chart at 20 cm improved [84]. With the same optical basis of a multifocal IOL, the Scharioth Macula Lens (SML) has a central optic zone with +10.00 D addition. Compared with a +6.00 D spectacle lens for near vision, SML reported 2.1 lines better visual acuity at 15 cm than the spectacle lens at 1 month [85]. Similar results to those of LMI were obtained with IOL-AMD after 4 months. This implant consists of a Galilean telescope in one eye with two hydrophobic IOLs, one negative and one positive [83]. Finally, the intra-ocular miniaturized telescope (IMT) takes advantage of corneal optical power. It is implanted in one eye, used for near vision, while the other eye is used for distance vision. At 1 year, 3.2 lines of improvement in near vision acuity in ETDRS was reported compared with baseline, remaining after 5 years of surgery [83, 86].

#### **Figure 4.**

*Example of the user-defined region or "bubble" where image can be magnified [82] (from https://tvst. arvojournals.org/article.aspx?articleid=2725386).*

**93**

*Training Reading Skills in Central Field Loss Patients: Impact of Clinical Advances…*

Relying on the development of technology, games have also undergone a revolution. Today, there are multiple games that can be played on iPad. AMD patients in a large percentage use personal electronic devices for playing games [87]. Due to these results, gaming could play an important role in earlier detection of AMD. Video games had been used to train visual acuity, fixation pattern and retinal sensitivity in patients with Stargardt disease [88]. Patients of this study played action video-game during 1 h per day each eye with alternate patching. Results showed an improvement of these visual functions, which opens a new option of

Reading involves the participation of different perceptive and cognitive processes. When a person suffers a pathology such as AMD, the vision in the central visual field is reduced and all the processes are altered, being necessary a rehabilitative intervention that determines the scope of the visual loss, helps to establish a new point of visual fixation and trains in the ocular movements, so that the reading becomes fluid and comprehensive. In this rehabilitative process, it is necessary to implement optical and non-optical aids that improve the visual functioning of the person affected by AMD. New electronic devices and access to digital information are producing changes in the visual rehabilitation strategies of people with AMD.

None of the authors have any conflict of interest on the devices or technology

ISLRR International Society for Low-vision Research and Rehabilitation

*DOI: http://dx.doi.org/10.5772/intechopen.88943*

**10.3 Gaming and electronic devices**

rehabilitation based on video-games.

**11. Conclusions**

**Conflict of interest**

described in this chapter.

ABI acquired brain injury ADL activities of daily living

CCTV close circuit television CFL central field loss CS contrast sensitivity CVF central visual field

HMD head-mounted display

IOL intra-ocular lens

KDT King-Devick test LMI Lipshitz mirror implant LVR low vision rehabilitation

AMD age-related macular degeneration

ETDRS early treatment diabetic retinopathy study

ICO International Council of Ophthalmology

MADRS Montgomery-Asberg Depression Rating Scale

IMT intra-ocular miniaturized telescope IReST International Reading Speed Texts

IVI impact of vision impairment

**Abbreviations**

*Training Reading Skills in Central Field Loss Patients: Impact of Clinical Advances… DOI: http://dx.doi.org/10.5772/intechopen.88943*

#### **10.3 Gaming and electronic devices**

Relying on the development of technology, games have also undergone a revolution. Today, there are multiple games that can be played on iPad. AMD patients in a large percentage use personal electronic devices for playing games [87]. Due to these results, gaming could play an important role in earlier detection of AMD. Video games had been used to train visual acuity, fixation pattern and retinal sensitivity in patients with Stargardt disease [88]. Patients of this study played action video-game during 1 h per day each eye with alternate patching. Results showed an improvement of these visual functions, which opens a new option of rehabilitation based on video-games.