Neural Mechanisms Underlying Astigmatism

Not Applicable

• Conditions: Astigmatism
• Interventions: Behavioral: perceptual training

• Registration Number: NCT03735602
• Lead Sponsor: Zhongshan Ophthalmic Center, Sun Yat-sen University

Brief Summary

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.

Detailed Description

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.

Study Timeline

• Study First Submitted: 2018-10-24
• Study First Submitted QC: 2018-11-07
• Study First Posted: 2018-11-08
• Study Start: 2019-07-01
• Status Verified: 2020-05
• Last Update Submitted: 2020-05-16
• Last Update Posted: 2020-05-19
• Primary Completion: 2021-03
• Study Completion: 2021-12

Recruitment & Eligibility

• Status: UNKNOWN
• Sex: All
• Target Recruitment: 20

Inclusion Criteria

• high astigmatism

Exclusion Criteria

• other types of disease (especially optical diseases) that may affect study

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: SINGLE_GROUP

Arm && Interventions

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

Primary Outcome Measures

Name	Time	Method
The change of the contrast sensitivity function tested by quick CSF	eight months	The quick CSF (contrast sensitivity function) measures contrast threshold by fitting raw data and calculating the Cutoff sensitivity frequency.
The change of contrast threshold tested by sweep visually evoked potential (VEP)	eight months	The contrast threshold was calculated by analyzing EEG(Electroencephalogram) data recorded with sweep visually evoked potential (VEP) paradigm.

Trial Locations

Locations (1)

Zhongshan Ophthalmic Center; 🇨🇳 Guangzhou, Guangdong, China