# Vision recovery in cortical blindness

> **NIH NIH R01** · UNIVERSITY OF ROCHESTER · 2022 · $486,913

## Abstract

In adulthood, stroke damage to the primary visual cortex (V1) causes a large, contralateral loss of conscious
vision referred to as hemianopia or cortical blindness (CB). Although this condition affects up to ½ million new
cases each year in the US alone, there is a total lack of accepted vision restoration therapies – in marked
contrast with early-onset physical therapies prescribed to those with motor cortex damage. Two decades of
work in chronic CB patients, whose deficits are deemed stable, permanent and thus amenable to scientific
study, have generated one method consistently able to recover vision after long-standing V1 damage: gaze-
contingent visual training to detect or discriminate stimuli in the blind field. Over the last 2 grant periods, we
have taken clear leadership in the field, providing hope that an effective therapy for CB may finally be on the
horizon. However, while characterizing training-induced recovery and its underlying mechanisms, we also
found that recovery in chronic CB requires months of daily training and the vision restored is low-contrast,
coarse, impaired by excessive internal processing noise and restricted to the blind field perimeter.
Accumulating evidence suggests that these limitations may occur because chronic patients have lost a
substantial portion of neurons that contribute to vision fundamentals not only in V1, but through retrograde
degeneration, in the dorsal lateral geniculate nucleus (dLGN) and retina. Our new pilot data show subacute CB
patients <6 months post-stroke to lack significant signs of degeneration, and more than half of subacutes
tested retained visual discrimination abilities in their blind field, which disappeared by the start of the chronic
period (6 months post-stroke). Moreover, when training was administered to subacutes, they recovered the
same discrimination abilities as chronics, but much faster, and with recovery extending deeper into their blind
field. These data form a strong premise for testing the hypothesis that substantial differences in plastic
potential between subacute and chronic V1-stroke visual systems can be exploited to maximize visual
restoration in CB, and that the extent of recovery attainable is limited by the amount of retrograde
degeneration sustained. We now propose to: (Aim 1) assess how visual performance relates to structural
evidence of retrograde degeneration in the subacute period post-V1-stroke. We will then (Aim 2) assess the
impact of subacute training on blind-field functions, the progression of retrograde degeneration and the
continued potential for training-induced recovery in the chronic period. Finally, we will (Aim 3) contrast
mechanistic substrates of perceptual learning in subacute & chronic CB. All in all, the work proposed is unique
in the field, which it stands to advance significantly by generating entirely new knowledge and understanding of
the change in visual plastic potential with time in the early period after permanent V1 damage in...

## Key facts

- **NIH application ID:** 10355460
- **Project number:** 5R01EY027314-06
- **Recipient organization:** UNIVERSITY OF ROCHESTER
- **Principal Investigator:** Krystel R Huxlin
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $486,913
- **Award type:** 5
- **Project period:** 2017-02-01 → 2026-01-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10355460

## Citation

> US National Institutes of Health, RePORTER application 10355460, Vision recovery in cortical blindness (5R01EY027314-06). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10355460. Licensed CC0.

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