Development of pattern vision following early and extended blindness

Kalia, Amy; Lesmes, Luis Andres; Dörr, Michael; Gandhi, Tapan Kumar; Chatterjee, Gobinda; Ganesh, Suma; Bex, Peter J.; Sinha, Pawan

doi:10.1073/pnas.1311041111

Cited by 94 publications

(86 citation statements)

References 46 publications

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“…This point is especially pertinent given the intersubject variability we see in our results. The variability, which is a common feature of many aspects of the vision of newly sighted children (18,49), does not yet have a satisfactory explanation such as age at treatment. Second, we have considered only one of the many face perception tasks humans perform.…”

Section: Discussionmentioning

confidence: 99%

Emergence of categorical face perception after extended early-onset blindness

Gandhi

Singh

Swami

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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It is unknown whether the ability to visually distinguish between faces and nonfaces is subject to a critical period during development. Would a congenitally blind child who gains sight several years after birth be able to acquire this skill? This question has remained unanswered because of the rarity of cases of late sight onset. We had the opportunity to work with five early-blind individuals who gained sight late in childhood after treatment for dense bilateral cataracts. We tested their ability to categorize patterns as faces, using natural images that spanned a spectrum of face semblance. The results show that newly sighted individuals are unable to distinguish between faces and nonfaces immediately after sight onset, but improve markedly in the following months. These results demonstrate preserved plasticity for acquiring face/ nonface categorization ability even late in life, and set the stage for investigating the informational and neural basis of this skill acquisition.face classification | blindness | visual learning | sight restoration | plasticity

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Section: Discussionmentioning

confidence: 99%

Emergence of categorical face perception after extended early-onset blindness

Gandhi

Singh

Swami

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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“…Improvements in the contrast sensitivity function has been noted in several (though not all) individuals who had sight restored at a young age (between the ages of 8-17 years) (Kalia et al 2014). This ability to show learning for the contrast sensitivity function may be age–dependent: improvements were not found in MM (Fine et al 2003a) or PD (Fine et al 2002a, a case of recovery from low vision).…”

Section: Adult Plasticitymentioning

confidence: 99%

Learning to see again: biological constraints on cortical plasticity and the implications for sight restoration technologies

et al. 2017

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The “bionic eye” – so long a dream of the future – is finally becoming a reality with retinal prostheses available to patients in both the US and Europe. However, clinical experience with these implants has made it apparent that the vision provided by these devices differs substantially from normal sight. Consequently, the ability to learn to make use of this abnormal retinal input plays a critical role in whether or not some functional vision is successfully regained. The goal of the present review is to summarize the vast basic science literature on developmental and adult cortical plasticity with an emphasis on how this literature might relate to the field of prosthetic vision. We begin with describing the distortion and information loss likely to be experienced by visual prosthesis users. We then define cortical plasticity and perceptual learning, and describe what is known, and what is unknown, about visual plasticity across the hierarchy of brain regions involved in visual processing, and across different stages of life. We close by discussing what is known about brain plasticity in sight restoration patients and discuss biological mechanisms that might eventually be harnessed to improve visual learning in these patients.

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“…Its operations are currently focused on India that has an estimated 200,000 to 700,000 blind children, nearly 40% of whom have preventable or treatable conditions [10-12]. Results from Project Prakash show that after treatment for congenital cataracts, patients are able to acquire proficiency on an array of visual dimensions, ranging from basic functions such as acuity and contrast sensitivity [13, 14] to more complex abilities such as face localization and classification, spatial imagery, and mapping between visual and haptic senses [15-17]. Although the children do not reach normal levels for basic visual functions, such as acuity and contrast sensitivity, these findings suggest that the visual system and its underlying neural mechanisms do retain enough plasticity to allow for significant improvements, even late in childhood.…”

Section: Introductionmentioning

confidence: 99%

Assessing the impact of a program for late surgical intervention in early-blind children

et al. 2017

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Objective Many blind children in the developing world are unable to obtain timely treatment due to lack of financial and medical resources. Can public health programs that identify and treat such children several years after the onset of blindness enhance their quality of life? The notion that visual development is subject to an early ‘critical period’ argues against this possibility. However, there are inadequate empirical data from humans on this issue. To address this need, we examined the quality of life of children living in India and who were treated for early-onset blindness (before one year of age), due to cataracts or corneal opacities. Study Design Survey study. Methods As part of an ongoing scientific effort named Project Prakash, we screened over 40,000 children in rural northern India to identify those suffering from early onset blindness. They were provided eye surgeries in a tertiary care ophthalmic center in New Delhi. We subsequently surveyed sixty-four Prakash children, ranging in age from 5 to 22 years, and obtained their responses on a multi-dimensional Quality of Life questionnaire. Results Nearly all of the subjects indicated that their quality of life had improved after treatment. Children reported marked enhancement in their mobility, independence and safety, as also in social integration. Surprisingly, we found no significant correlations between quality of life metrics and factors such as age at treatment, gender, time since treatment, and pre- and post- surgery acuity. Conclusions A key question for public health policy makers is whether a program of surgical intervention for older blind children is likely to be beneficial, or if the resources are better spent on rehabilitation via vocational training and assistive devices. The marked improvements in quality of life we find in our data strongly argue for the provision of surgical care regardless of a child’s age.

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Development of pattern vision following early and extended blindness

Cited by 94 publications

References 46 publications

Emergence of categorical face perception after extended early-onset blindness

Emergence of categorical face perception after extended early-onset blindness

Learning to see again: biological constraints on cortical plasticity and the implications for sight restoration technologies

Assessing the impact of a program for late surgical intervention in early-blind children

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