Neural Mechanisms Underlying Astigmatism

This study is to compare the contrast sensitivity function and neural response to gratings before and after the orientation discrimination task in the astigmatism or amblyopia patients.

The presence of astigmatism can lead to substantial reductions in visual performance in a variety of clinical vision measures and functional visual tasks. However, the neural mechanisms underlying the astigmatism remains unknown. The current study recruited three groups (patients with with-the-rule astigmatism and amblyopia, patients with with-the-rule astigmatism but without amblyopia, normal controls) of subjects and patients receive perceptual learning training (orientation discrimination task) which lasts for around 15 days. This main aim is to compare the contrast sensitivity function and neural response to gratings before and after the orientation discrimination task in the astigmatism or amblyopia patients. Patients with astigmatism or amblyopia were included in this study. All participants underwent an ophthalmic examination that included slit-lamp biomicroscopy, visual acuity, quick CSF under full optical correction, 9-SF life quality questionnaire and fundus examination.

Orientation discrimination task, which is a cognitive task. Patients were trained for 1 hour per day, 15 days in total.

The quick CSF (contrast sensitivity function) measures contrast threshold by fitting raw data and calculating the Cutoff sensitivity frequency.

The contrast threshold was calculated by analyzing EEG(Electroencephalogram) data recorded with sweep visually evoked potential (VEP) paradigm.

Inclusion Criteria: high astigmatism Exclusion Criteria: other types of disease (especially optical diseases) that may affect study