# Psychophysical assessment of face perception deficits in adults with amblyopia through top-down and bottom-up visual processing pathways

## TL;DR

This study finds that adults with amblyopia have impaired face perception, especially under low stimulation conditions.

## Contribution

The study introduces a novel psychophysical approach to assess face perception deficits in amblyopia through top-down and bottom-up processing.

## Key findings

- Amblyopic eyes showed significantly higher face detection thresholds than healthy controls.
- Amblyopic patients had lower accuracy at 20 and 67% stimulation intensities compared to controls.
- No significant differences in false alarm rate or reaction time were observed in the Toast task.

## Abstract

This study aims to investigate face perception ability in adult patients with amblyopia.

We conducted two psychophysical experiments. The Face-detection task involved 25 amblyopic patients and 25 healthy controls, using face stimulation at 6 stimulation intensities. The Toast task included 16 amblyopic patients and 15 healthy controls, with pure noise images and semantic cues designed to induce face perception. We recorded accuracy and reaction times (RT) and used the Kruskal-Wallis test with Wilcoxon comparisons to analyze group differences.

In the Face-detection task, amblyopic eyes (AE) exhibited significantly higher face detection thresholds than healthy controls (P < 0.05), indicating face detection deficit. AE showed lower accuracy at 20 and 67% stimulation intensities compared with HC and fellow eyes (Ps < 0.01). The Toast task revealed no significant differences in false alarm rate or RT were observed between groups (P > 0.1).

This study shows that patients with amblyopia have impaired face perception, with higher threshold and lower accuracy, especially under lower stimulation conditions. These findings highlight the need for further research to understand the neural basis of these deficits and explore potential treatments. Ultimately, these study results may provide valuable insights and fill an important gap in the psychophysical understanding of amblyopia.