[Home](./index.md) > [puppeteer](./puppeteer.md) > [Page](./puppeteer.page.md) > [emulateVisionDeficiency](./puppeteer.page.emulatevisiondeficiency.md) ## Page.emulateVisionDeficiency() method Signature: ```typescript emulateVisionDeficiency(type?: VisionDeficiency): Promise; ``` ## Parameters | Parameter | Type | Description | | --- | --- | --- | | type | VisionDeficiency | | Returns: Promise<void>