puppeteer/website/versioned_docs/version-9.1.1/puppeteer.page.emulatevisiondeficiency.md
2021-08-10 11:09:48 +01:00

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[Home](./index.md) &gt; [puppeteer](./puppeteer.md) &gt; [Page](./puppeteer.page.md) &gt; [emulateVisionDeficiency](./puppeteer.page.emulatevisiondeficiency.md)
## Page.emulateVisionDeficiency() method
Simulates the given vision deficiency on the page.
<b>Signature:</b>
```typescript
emulateVisionDeficiency(type?: Protocol.Emulation.SetEmulatedVisionDeficiencyRequest['type']): Promise<void>;
```
## Parameters
| Parameter | Type | Description |
| --- | --- | --- |
| type | Protocol.Emulation.SetEmulatedVisionDeficiencyRequest\['type'\] | the type of deficiency to simulate, or <code>'none'</code> to reset. |
<b>Returns:</b>
Promise&lt;void&gt;
## Example
```js
const puppeteer = require('puppeteer');
(async () => {
const browser = await puppeteer.launch();
const page = await browser.newPage();
await page.goto('https://v8.dev/blog/10-years');
await page.emulateVisionDeficiency('achromatopsia');
await page.screenshot({ path: 'achromatopsia.png' });
await page.emulateVisionDeficiency('deuteranopia');
await page.screenshot({ path: 'deuteranopia.png' });
await page.emulateVisionDeficiency('blurredVision');
await page.screenshot({ path: 'blurred-vision.png' });
await browser.close();
})();
```