Training on spatiotemporal masking improves crowded and uncrowded visual acuity.

Area of Science:

• Vision science
• Neuroscience
• Perceptual learning

Background:

• Spatial crowding negatively impacts visual perception and object recognition, especially with short presentation times.
• Reduced visual acuity (VA) due to crowding is observed in young individuals and those with presbyopia.
• Perceptual learning has demonstrated efficacy in enhancing near VA across various age groups and conditions, including presbyopia and amblyopia.

Purpose of the Study:

• To objectively measure crowded visual acuity (VA) in uncorrected presbyopes with naturally decreased VA.
• To investigate the impact of perceptual training on crowded VA in this population.
• To determine if training, previously shown to improve reading, affects crowded VA.

Main Methods:

• Visual acuity (VA) was assessed under crowded and uncrowded conditions using letter identification tasks with brief stimulus durations (34-116 ms).
• Participants underwent perceptual training using the GlassesOff mobile application, focusing on detecting Gabor stimuli under spatial and temporal masking.
• Training was conducted on iOS devices from a 40 cm distance.

Main Results:

• A significant reduction in crowded VA was observed in the fovea of presbyopes prior to training.
• Perceptual training led to significant improvements in letter identification under both crowded and uncrowded conditions for all stimulus durations.
• Post-training, the crowded VA threshold improved to match the pre-training uncrowded VA threshold.

Conclusions:

• Perceptual training effectively enhances crowded visual acuity (VA) in individuals with presbyopia, enabling them to overcome reduced near vision.
• The improvements suggest that enhanced spatial and temporal processing from perceptual learning can benefit crowded VA.
• These findings indicate potential transfer effects of perceptual training to complex visual functions like reading and object recognition.