<!-- Do not edit this file. It is automatically generated by API Documenter. --> [Home](./index.md) > [puppeteer](./puppeteer.md) > [Page](./puppeteer.page.md) > [emulateVisionDeficiency](./puppeteer.page.emulatevisiondeficiency.md) ## Page.emulateVisionDeficiency() method <b>Signature:</b> ```typescript emulateVisionDeficiency(type?: VisionDeficiency): Promise<void>; ``` ## Parameters | Parameter | Type | Description | | --- | --- | --- | | type | VisionDeficiency | | <b>Returns:</b> Promise<void>