Training under spatial and temporal constraints improves crowded and uncrowded visual acuity
This study explored the effects of perceptual training using the GlassesOff’s mobile application on naturally decreased crowded visual acuity in uncorrected presbyopia. After training, the crowded acuity reached the level of the uncrowded acuity measured before training, indicating that training enabled overcoming the effects of crowding. More efficient spatial and temporal processing induced by perceptual learning that may be generalized to improve complex visual functions, such as reading and object recognition, is suggested. Yehezkel, O., Sterkin, A., Lev, M., & Polat, U. (2015). Training on spatiotemporal masking improves crowded and uncrowded visual acuity.
Crowding is proportional to visual acuity in young and aging eye
The relationships between varying visual acuity and crowding in the fovea was tested using GlassesOff’s mobile application in 195 participants, with an age range of 20 to 68 and acuity gradually reduced due to normal ageing. The results show that crowding is proportional to acuity, with this proportionality affected by acuity-age dependency, with a non-linear S-shaped pattern, compatible with both the onset age of presbyopia and a saturation in the oldest age group due to eccentricity effects. The high variance in the crowding in the young group, even before the onset age of presbyopia, suggests crowding conditions with limited presentation times as a highly sensitive measure of VA, predictive of visual performance in complex tasks, such as reading. Yehezkel, O., Sterkin, A., Lev, M., & Polat, U. (2015). Training on spatiotemporal masking improves crowded and uncrowded visual acuity.
Training improves visual processing speed and generalizes to untrained functions.
GlassesOff’s mobile application was used to train foveal vision of young participants in a recent study conducted at Charité – Universitätsmedizin in Berlin and published in Nature’s Scientific Reports. Several significant improvements in spatio-temporal visual functions were observed, including near and non-trained far distances. A remarkable transfer to visual acuity measured under crowded conditions resulted in reduced processing time of 81 ms, in order to achieve 6/6 acuity. In addition, enhanced processing speed may lead to overcoming foveal crowding and hence enable generalization to other visual functions. Lev, M., Ludwig, K., Gilaie-Dotan, S., Voss, S., Sterzer, P., Hesselmann, G., & Polat, U. (2014b). Training improves visual processing speed and generalizes to untrained functions.
Training-induced recovery of low-level vision followed by more complex perceptual improvements in developmental object and face agnosia
This study is a case report with a 20 year-old subject, LG, suffering from a developmental object and face agnosia (inability to recognize objects or faces), considered untreatable. LG’s visual functions such as visual acuity, crowding effects, and contour integration were underdeveloped relative to normal adult vision, corresponding to or poorer than those of 5-6 year olds. Following training on the technology developed by GlassesOff for a period of nine months, his visual acuity, crowding, binocular stereopsis, and contour integration improved significantly to a near-age-level performance, persistent for more than 4 years. More complex functions, such as contour integration, improved to age-level performance. Minor improvement was also observed in LG’s object recognition and part integration capabilities. Collectively, these results suggest that corrective training using the GlassesOff technology, even in the adult visual system, can prove effective, and its enduring effects are the basis for a revival of a developmental cascade that can lead to reduced perceptual impairments. Lev, M., Gilaie-Dotan, S., Gotthilf-Nezri, D., Yehezkel, O., Brooks, J.L., Perry, A., Bentin, S., Bonneh, Y. & Polat, U. (2014). Training-induced recovery of low-level vision followed by midlevel perceptual improvements in developmental object and face agnosia
Training the brain to overcome the effect of aging on the human eye
The effectiveness of the GlassesOff product was examined in a study conducted at the University of California at Berkeley and published in Nature’s Scientific Reports. This study clearly demonstrated the significant benefit of the GlassesOff training program for reading abilities and eye age. Moreover, cutting-edge optometric equipment allowed the scientists to unequivocally determine that the actual source of the observed benefits is solely in the brain and not in the optics of the eyes. Polat, U., Schor, C.,Tong, JL., Zomet, A., Lev, M., Yehezkel, O., Sterkin, A., Levi, D. (2012) Scientific Reports, 2 (278).
Uncovering foveal crowding?
Visual crowding impairs object recognition in clutter, setting a fundamental limit on visual perception, but always found only in peripheral vision. Here, for the first time, we show that limiting stimulus availability induces crowding in the fovea. Enabling enough processing time in the fovea, for instance, by processing speed enhancement following perceptual learning, both young and presbyopes overcome this effect, improves visual functions relying on central vision, such as reading and driving. Lev, M., Yehezkel, O., Polat, U. (2014) Scientific Reports, 4 (4067).
Improving vision in adult amblyopia by perceptual learning
Perceptual training was applied to an adult visual system with amblyopia. Training yielded significant benefits that transfer to higher visual functions, resulting in a two-fold improvement in contrast sensitivity and in letter-recognition tasks in patients between 9 and 55 years old. This is the first evidence for a remarkable vision improvement following perceptual learning in a condition previously acknowledged as untreatable in adults. Polat, U., Ma-Naim, T., Belkin, M., & Sagi, D. (2004) Proc Natl Acad Sci U S A, 101(17): 6692-6697.
Making perceptual learning practical to improve visual functions
Generalization, or transfer, of gains acquired on a trained task to other functions is crucial for both understanding the neural mechanisms and the practical values of the training. This study describes a perceptual learning method applied to amblyopia, myopia and presbyopia. The gains were transferred to visual acuity, processing speed and reaction time. Thus, perceptual learning can become a practical method for improving visual functions in people with impaired or blurred vision. Polat U. (2009) Vision Res, 49(21) 2566-2573.
Learning to be fast: gain accuracy with speed
The effectiveness of perceptual learning on contrast detection in young adults was tested using behavioral and neurophysiological (Event-Related Potentials, ERPs) measurements. A remarkable improvement in all behavioral measurements, including sensitivity and reaction time, along with shorter latency and increased amplitude of an ERP marker of neuronal interactions within the visual cortex of the brain. Thus, perceptual learning that strengthens inter-neuronal interaction results in a faster processing speed and higher contrast sensitivity. Sterkin, A., Yehezkel, O., Polat, U. (2011) Vision Res. (61) 115-124
Neuroplasticity following perceptual learning for visual improvement
The aim of this review is to show that perceptual learning can be applied for practical purposes to improve visual functions of people with special needs. Prof. Polat predicts that perceptual learning methodology will be modified in the near future into complementary or standalone procedures to aid care providers in treating and improving a variety of visual functions that are not addressed by conventional treatment. Polat, U. (2009) Expert Rev. Ophthalmol. 4(6) 573-576.
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