puppeteer/docs/api/puppeteer.page.emulatevisiondeficiency.md

---
sidebar_label: Page.emulateVisionDeficiency
---
# Page.emulateVisionDeficiency() method

Simulates the given vision deficiency on the page.

**Signature:**

```typescript
class Page {emulateVisionDeficiency(type?: Protocol.Emulation.SetEmulatedVisionDeficiencyRequest['type']): Promise<void>;}
```

## Parameters

|  Parameter | Type | Description |
|  --- | --- | --- |
|  type | Protocol.Emulation.SetEmulatedVisionDeficiencyRequest\['type'\] | <i>(Optional)</i> the type of deficiency to simulate, or <code>'none'</code> to reset. |

**Returns:**

Promise&lt;void&gt;

## Example


```ts
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();
})();
```