**5. Emerging trends in the field**

Traditionally, VR in AMD patients includes training in eccentric vision and learning to use different optical and electronic magnifiers. However, some authors have recently studied the effects of new strategies, such as Barraza-Bernal et al. [74], who conducted a study with fifteen subjects with normal vision under simulation conditions, showing that PRL can be induced in a specific area by systematic relocation of stimuli.

Similarly, Morales et al. discuss improving the fixation stability in the PRL through biofeedback fixation training (BFT), which consist of slightly moving the gaze towards the training locus during different sessions [75]. Another training paradigm integrating oculomotor control and pattern recognition has also been evaluated, demonstrating that these strategies combined are capable of inducing a PRL over a short period of time in eight subjects with normal vision and a simulated central scotoma [76].

There are several studies that have been carried out to determine the effectiveness of repetitive, perceptual learning as an intervention approach for VR. This approach refers to the improvement in the execution of perceptual tasks as a consequence of training.

Perceptual learning has been found to have neural correlates in visual cortex, which declines with age. Learning effects in older adults are shown to be less than in younger people and are transferred only for the typeface and the retinal location trained. Causes may be a lower visual base span, decreased attention when exercising eccentricity, and less retention of what is learned over time.

People with AMD have a lower visual span, which contributes to a lower peripheral reading speed. According to Legge et al. [77], peripheral reading speed may improve if the size of the peripheral visual span is enlarged, and training based on letter-recognition trials has shown to extend the visual span, contributing to improve reading speed among older adults [78]. These studies [79] were carried out using trigrams, while Bernard et al. [80] sough to find out if a greater benefit can be obtained by using trigrams based on the most commonly used combinations in the English language, determining that the effects of perceptual learning may not be linked to the type of related letters.

Among several studies that have tried to determine the benefits of perpetual learning, some differentiate the way in which texts are presented. Among those using RSVP, there are differences between the vertical and horizontal presentation of text. For example, Yu et al. [81] found that lower speed in vertical presentation corresponds to a decrease in the visual span for vertical reading.

Chung demonstrated that perceptual learning can improve RSVP reading speed in people with AMD after training [82]. Face discrimination and recognition can also be reliably improved in patients with AMD using perceptual learning on face discrimination tasks [83]. Furthermore, Liu et al. [84], who trained people with severe visual impairment (due to different conditions, including AMD) on a visual search task, observed that both search speed and accuracy of the search improved after training, with the improvements being maintained for a period of time at least one month.

Pijnacker et al. [85] proposed to evaluate whether perceptual learning obtains similar results compared to eccentric vision training and oculomotor training, finding in all these interventions effective methods for reading rehabilitation in AMD patients. On the other hand, Seiple et al. [86] supported the efficacy of ocular movement control over eccentric viewing training and RSVP when compared to people with AMD, which does not imply considering the other methods as ineffective.
