Vision after 53 Years of Blindness

Abstract

Several studies have shown that visual recovery after blindness that occurs early in life is never complete. The current study investigated whether an extremely long period of blindness might also cause a permanent impairment of visual performance, even in a case of adult-onset blindness. We examined KP, a 71-year-old man who underwent a successful sight-restoring operation after 53 years of blindness. A set of psychophysical tests designed to assess KP's face perception, object recognition, and visual space perception abilities were conducted six months and eight months after the surgery. The results demonstrate that regardless of a lengthy period of normal vision and rich pre-accident perceptual experience, KP did not fully integrate this experience, and his visual performance remained greatly compromised. This was particularly evident when the tasks targeted finer levels of perceptual processing. In addition to the decreased robustness of his memory representations, which was hypothesized as the main factor determining visual impairment, other factors that may have affected KP's performance were considered, including compromised visual functions, problems with perceptual organization, deficits in the simultaneous processing of visual information, and reduced cognitive abilities.

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

“…In humans, the effects of altered visual experience on higher-level vision comes from case-studies of patients that have had their sight ‘restored’ after prolonged vision loss by ophthalmological procedures such as cataract (Fine et al 2002b, Ostrovsky et al 2009, Sinha et al 2013, McKyton et al 2015) or corneal replacement surgery (Fine et al 2003b, Sikl et al 2013). 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).…”

“…Interestingly these deficits are observable both in individuals who have sight restored in late childhood (Sinha et al 2013) and in a patient, KP, who lost vision at 17, and had his sight restored at age 71 (Sikl et al 2013). Thus, the sensitive period for deprivation appears to be broader (extending well into the teenage years) than the critical period for recovering normal vision.…”

Development of pattern vision following early and extended blindness

“…This study was conducted as part of Project Prakash, a joint scientific and humanitarian effort to treat curable blindness in India and to investigate the resulting course of visual development (20). Access to this population allowed us to examine contrast sensitivity across a large sample of sight restoration patients compared with previous reports (16)(17)(18)(21)(22)(23). Consequently, we could also explore individual differences in contrast sensitivity development.…”

Learning to See Again: Biological Constraints on Cortical Plasticity and the Implications for Sight Restoration Technologies

“…Impairments in shape processing, object recognition, and face processing are also observed in sight recovery patients, and these persist even after more than a decade of restored optical sight (Huber et al 2015). Interestingly these deficits are observable both in individuals who have sight restored in late childhood (Sinha et al 2013) and in a patient, KP, who lost vision at 17, and had his sight restored at age 71 (Sikl et al 2013). Thus, the sensitive period for deprivation appears to be broader (extending to at least well into the teenage years) than the critical period for recovering normal vision.…”

“…Similarly, training monkeys to discriminate novel visual stimuli causes the emergence of a population of IT neurons which respond selectively to these novel stimuli (Kobatake et al 1998, DiCarlo andMaunsell 2000), or which become capable of distinguishing between them (Jagadeesh et al 2001). 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 In human, the effects of altered visual experience on higher-level vision comes from case-studies of patients that have had their sight 'restored' after prolonged vision loss, either by ophthalmological procedures (including cataract (Fine et al 2002b, Ostrovsky et al 2009, Sinha et al 2013, McKyton et al 2015 or corneal replacement surgery (Fine et al 2003b, Sikl et al 2013. 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).…”