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Updated: Oct 28, 2025
Optic Nerve Transection: A Model of Adult Neuron Apoptosis in the Central Nervous System
Published on: May 12, 2011
Optic Tract Shrinkage Limits Visual Restoration After Occipital Stroke
Berkeley K Fahrenthold1, Matthew R Cavanaugh1, Subin Jang1
1Flaum Eye Institute (B.K.F., M.R.C., S.J., K.R.H.), University of Rochester, NY. Wellcome Centre for Integrative Neuroimaging, FMRIB, Nuffield Department of Clinical Neurosciences, University of Oxford, United Kingdom. Department of Neurorehabilitation and Therapy Services, The National Hospital for Neurology and Neurosurgery, Queen Square, London, United Kingdom.
Optic tract (OT) shrinkage after stroke predicts visual recovery potential. While visual restoration training doesn't reverse OT degeneration, patients with less shrinkage show better vision improvement.
Area of Science:
- Neuroscience
- Ophthalmology
- Radiology
Background:
- Primary visual cortex (V1) damage causes vision loss and trans-synaptic retrograde degeneration.
- Optic tract (OT) shrinkage is a consequence of V1 damage.
Purpose of the Study:
- To investigate if OT degeneration impacts visual recovery from training.
- To determine if visual restoration training affects OT shrinkage.
Main Methods:
- 36 patients with unilateral occipital stroke underwent MRI to measure OT volumes and calculate laterality indices (LI).
- 14 chronic patients received daily visual restoration training for ~1 year.
- Visual field recovery was assessed using Humphrey perimetry.
Main Results:
- OT shrinkage (LI>0) was detectable by ~7 months post-stroke, with significant variability.
- Visual training did not alter OT shrinkage (LI).
- Chronic patients with minimal baseline OT shrinkage (LI≈0) showed greater visual field recovery.
Conclusions:
- Optic tract shrinkage is detectable via MRI around 7 months post-stroke.
- OT shrinkage serves as a biomarker for predicting visual recovery potential in stroke patients undergoing visual training.
- Visual restoration training does not reverse existing OT degeneration but can lead to functional recovery in patients with less shrinkage.
