Donepezil Does Not Enhance Perceptual Learning in Adults with Amblyopia: A Pilot Study

Area of Science:

• Neuroscience
• Ophthalmology
• Cognitive Science

Background:

• Amblyopia, or 'lazy eye,' causes significant visual deficits, often persisting into adulthood.
• Perceptual learning (PL) shows promise for vision recovery in adults with amblyopia.
• Neuromodulators are being investigated for their potential to enhance adult neural plasticity.

Purpose of the Study:

• To investigate whether donepezil, a cholinesterase inhibitor, enhances visual perceptual learning (PL) in adults diagnosed with amblyopia.
• To assess the impact of donepezil on contrast sensitivity, learning rate, and transfer effects in amblyopic individuals.

Main Methods:

• A pilot study involving nine adults with amblyopia who underwent training on a low-contrast single-letter identification task with daily donepezil (5 mg).
• Performance was evaluated over 10,000 trials, measuring contrast sensitivity improvements and transfer effects to acuity and crowding tasks.
• A second training phase focused on a crowding task with donepezil administration for six participants.

Main Results:

• Participants showed improved contrast sensitivity but at a slower rate and magnitude compared to previous studies without donepezil.
• No significant differences in transfer of learning to acuity or crowding tasks were observed with donepezil.
• Second training phase on a crowding task yielded significant learning in only one participant, suggesting donepezil may impede PL in this context.

Conclusions:

• Cholinergic enhancement with donepezil does not appear to improve or accelerate visual PL for single-letter identification in adults with amblyopia.
• Donepezil administration during training may potentially inhibit learning and transfer, particularly for tasks involving visual crowding.
• Further research is needed to understand the role of neuromodulators in adult amblyopia treatment.